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1.  Risk factors for gastric cancer in Latin-America: a meta-analysis 
Cancer causes & control : CCC  2012;24(2):217-231.
Latin America has among the highest gastric cancer incidence rates in the world, for reasons that are still unknown. In order to identify region-specific risk factors for gastric cancer, we conducted a meta-analysis summarizing published literature.
Searches of PubMed and regional databases for relevant studies published up to December 2011 yielded a total of 29 independent case-control studies. We calculated summary odds ratios (OR) for risk factors reported in at least five studies, including socioeconomic status (education), lifestyle habits (smoking and alcohol use), dietary factors (consumption of fruits, total vegetables, green vegetables, chili pepper, total meat, processed meat, red meat, fish and salt) and host genetic variants (IL1B-511T, IL1B-31C, IL1RN*2, TNFA-308A, TP53 codon 72 Arg and GSTM1 null). Study-specific ORs were extracted and summarized using random-effects models.
Chili pepper was the only region-specific factor reported in at least five studies. Consistent with multifactorial pathogenesis, smoking, alcohol use, high consumption of red meat or processed meat, excessive salt intake and carriage of IL1RN*2 were each associated with a moderate increase in gastric cancer risk. Conversely, higher levels of education, fruit consumption, and total vegetable consumption were each associated with a moderately decreased risk. The other exposures were not significantly associated. No prospective study data were identified.
Risk factor associations for gastric cancer in Latin America are based on case-control comparisons that have uncertain reliability, particularly with regard to diet; the specific factors identified and their magnitudes of association are largely similar to those globally recognized. Future studies should emphasize prospective data collection and focus on region-specific exposures that may explain high gastric cancer risk.
PMCID: PMC3961831  PMID: 23224270
epidemiology; gastric cancer; Latin-America; meta-analysis; risk factors
2.  Cytokine signaling pathway polymorphisms and AIDS-related non-Hodgkin lymphoma risk in the Multicenter AIDS Cohort Study 
AIDS (London, England)  2010;24(7):1025-1033.
Cytokine stimulation of B-cell proliferation may be an important etiologic mechanism for acquired immunodeficiency syndrome (AIDS)-related non-Hodgkin lymphoma (NHL). The Epstein-Barr virus may be a co-factor, particularly for primary central nervous system (CNS) tumors, which are uniformly EBV-positive in the setting of AIDS. Thus, we examined associations of genetic variation in IL10 and related cytokine signaling molecules (IL10RA, CXCL12, IL13, IL4, IL4R, CCL5 and BCL6) with AIDS-related NHL risk and evaluated differences between primary CNS and systemic tumors. We compared 160 Multicenter AIDS Cohort Study (MACS) participants with incident lymphomas, of which 90 followed another AIDS diagnosis, to HIV-1-seropositive controls matched on duration of lymphoma-free survival post-HIV-1 infection (N=160) or post-AIDS diagnosis (N=90). We fit conditional logistic regression models to estimate odds ratios (ORs) and 95 percent confidence intervals (95%CIs). Carriage of at least one copy of the T allele for the IL10 rs1800871 (as compared to no copies) was associated with decreased AIDS-NHL risk specific to lymphomas arising from the CNS (CC vs. CT/TT: OR=0.3; 95%CI: 0.1, 0.7) but not systemically (CC vs. CT/TT: OR=1.0; 95%CI: 0.5, 1.9) (Pheterogeneity=0.03). Carriage of two copies of the “low IL10” haplotype rs1800896_A/rs1800871_T/rs1800872_A was associated with decreased lymphoma risk that varied by number of copies (Ptrend=0.02). None of the ORs for the other studied polymorphisms was significantly different from 1.0. Excessive IL10 response to HIV-1 infection may be associated with increased risk of NHL, particularly in the CNS. IL10 dysregulation may be an important etiologic pathway for EBV-related lymphomagenesis.
PMCID: PMC3950937  PMID: 20299965
cytokine; SNPs; AIDS-related lymphoma
3.  Increased Levels of Circulating Cytokines with HIV-Related Immunosuppression 
Cytokines may contribute to the severity of CD4 cell depletion with human immunodeficiency virus (HIV) infection, but quantitative relationships are not well defined. Serum and plasma from 181 HIV-infected individuals were tested with Millipore 30-plex Luminex cytokine assays. Within-individual correlations among cytokines were summarized by two-dimensional hierarchical cluster analysis. Associations with age, sex, race, CD4 count, and HIV viral load were determined with linear regression models. Tests for statistical significance were corrected for multiple comparisons, using a false discovery rate of 0.1. African-Americans had significantly higher levels than whites of six cytokines (IL-2, IL-5, IL-7, IL-15, fractalkine, and IFN-γ), and lower levels of MCP-1. Females had higher fractalkine levels than males. Age was not associated with levels of any cytokine. Six cytokines, including the T-helper (Th) type 1 cytokine IL-15, the Th2 cytokines IL-1ra and IL-10, the chemokines fractalkine and MCP-1, and the growth factor G-CSF were each inversely associated with CD4 count; no cytokine was directly associated with CD4 count. Fractalkine was directly associated with HIV viral load, adjusted for CD4 count. Cytokines clustered by primary function (e.g., Th1, Th2, proinflammatory, chemokines, or growth factors) whereas individuals clustered according to cytokine levels (generally high, intermediate, or low) had significantly different CD4 counts [medians (interquartile range) of 60 (17–162), 131 (62–321), and 155 (44–467), respectively; p<0.0001]. CD4 deficiency is associated with generalized increases in cytokines of various functions. Racial differences in cytokine response to HIV infection could contribute to disparities in disease progression.
PMCID: PMC3399552  PMID: 21962239
4.  Sex Hormones, Hormonal Interventions and Gastric Cancer Risk: A Meta-Analysis 
Estrogens may influence gastric cancer risk but published studies are inconclusive. We therefore performed a meta-analysis addressing the associations of gastric cancer in women with menstrual and reproductive factors, and with use of estrogen- and antiestrogen-related therapies. Searches of PubMed up to June, 2011 and review of citations yielded a total of 28 independent studies including at least one exposure of interest. Random effects pooled estimates of relative risk (RR) and corresponding 95% confidence intervals (CI) were calculated for eight exposures reported in at least five studies, including: age at menarche, age at menopause, years of fertility, parity, age at first birth, oral contraceptive use, hormone replacement therapy (HRT), and tamoxifen treatment. Longer years of fertility (RR= 0.74; 95% CI= 0.63 to 0.86) and HRT (RR= 0.77, 95% CI= 0.64 to 0.92) were each associated with decreased gastric cancer risk. Conversely, tamoxifen treatment was associated with increased risk (RR= 1.82, 95% CI= 1.39 to 2.38). The other five exposures were not significantly associated. Our analysis supports the hypothesis that longer exposure to estrogen effects of either ovarian or exogenous origin may decrease risk of gastric cancer. Additional studies are warranted to extend this finding and to identify the underlying mechanisms.
PMCID: PMC3315355  PMID: 22028402
Gastric Cancer; Hormone Therapy; Menstrual Factors; Reproductive Factors; Tamoxifen
5.  Meta-analysis shows that prevalence of Epstein-Barr virus-positive gastric cancer differs based on sex and anatomic location 
Gastroenterology  2009;137(3):824-833.
Background & Aims
Epstein-Barr virus (EBV) has been causally associated with cancer; some gastric carcinomas have a monoclonal EBV genome in every cancer cell, indicating that they arose from a single infected progenitor cell. However, the proportion of EBV-positive gastric carcinomas is uncertain and the etiological significance is unknown.
We conducted a meta-analysis of 70 studies including 15,952 cases of gastric cancer assessed by in situ hybridization for EBV-encoded small RNA.
The pooled prevalence estimate of EBV-positivity was 8.7% (95% CI: 7.5, 10.0) overall, with a two-fold difference by sex: 11.1% (95% CI: 8.7, 14.1) of gastric cancer cases in males vs. 5.2% (95% CI: 3.6, 7.4) of cases in females. Tumors arising in the gastric cardia (13.6%) or corpus (13.1%) were more than twice as likely to be EBV-positive as those in the antrum (5.2%; p<0.01 for both comparisons). EBV-prevalence was four times higher (35.1%) for tumors in post-surgical gastric stump/remnants. Over 90% of lymphoepithelioma-like carcinomas were EBV-positive but only 15 studies reported any cases of this type; prevalence did not significantly differ between the more common diffuse (7.6%) and intestinal (9.5%) histologies. EBV-prevalence was similar in cases from Asia (8.3%), Europe (9.2%), and the Americas (9.9%).
EBV-positive gastric cancers greatly differ from other gastric carcinomas based on sex, anatomic subsite, and surgically disrupted anatomy, indicating that it is a distinct etiologic entity. Epidemiologic studies comparing EBV-positive and -negative gastric cancers are warranted to investigate EBV’s role in gastric carcinogenesis.
PMCID: PMC3513767  PMID: 19445939
Epstein-Barr virus; gastric cancer; meta-analysis; prevalence
6.  Circulating cytokine levels, Epstein-Barr viremia and risk of acquired immunodeficiency syndrome-related non-Hodgkin lymphoma 
American Journal of Hematology  2011;86(10):875-878.
Cytokine dysregulation and decontrol of Epstein-Barr virus (EBV) latency by human immunodeficiency virus (HIV) infection are potential mechanisms for acquired immunodeficiency syndrome (AIDS)-related non-Hodgkin lymphoma (NHL). We therefore assessed circulating blood levels in pre-diagnosis plasma or serum from 63 AIDS-related NHL cases 0.1 – 2.0 (median 1.0) years pre-NHL and 181 controls matched for CD4+ T-cell count. Cytokines were measured by Millipore 30-plex Luminex assays and cell-free EBV DNA detected by polymerase chain reaction (PCR). Correlations in multiplex cytokine levels were summarized by factor analysis. Individual cytokines and their principal factors were analyzed for associations with NHL by conditional logistic regression. Cases had higher levels for 25 of the 30 cytokines. In analyses of cytokine profiles, cases had significantly higher scores for a principal factor primarily reflecting levels of interleukin (IL)-4, IL-5, IL-13, and granulocyte-macrophage colony stimulating factor (four gene products with coordinated transcription in vitro), as well as IL-1alpha. Epstein-Barr viremia was not significantly associated based on 113 evaluable samples without PCR inhibition. We found increases of T-helper type 2 interleukins and generalized elevations of other inflammatory cytokines and growth factors up to two years before AIDS-NHL. Cytokine-mediated hyperstimulation of B-cell proliferation may play a role in AIDS-related lymphomagenesis.
PMCID: PMC3320652  PMID: 22022727
7.  Systemic Cytokine Levels and Subsequent Risk of Gastric Cancer in Chinese Women 
Cancer Science  2011;102(10):1911-1915.
The control of the host cytokine network is known to influence gastric cancer susceptibility; the specific inflammatory responses in gastric carcinogenesis remain unclear.
We prospectively examined the relationships of plasma levels of interleukin (IL)-1β, IL6, IL8 and tumor necrosis factor (TNF)-α to gastric cancer risk within The Shanghai Women’s Health Study. Two controls were matched to each case by age, menopausal status and sample collection parameters. The associations of gastric cancer risk and tertile of cytokine levels were estimated by odds ratios (ORs) and 95 per cent confidence intervals (% CIs) from conditional logistic regression, adjusting for education.
During a median follow-up period of 4 years (range: 0.1–8), 141 women developed gastric cancer and were matched to 282 cancer-free study participants. Elevated levels of plasma IL6 were associated with an increased risk of gastric cancer (Ρtrend=0.04). Risk increased 70% (OR=1.7, 95% CI, 1.0, 3.0) for women in the highest tertile (> 4 pg/mL) of IL-6 compared to those in the lowest tertile (<1.8 pg/mL). The association with IL6 was stronger after 4 years of follow-up (OR=2.6, 95% CI, 1.0, 6.7 for highest vs. lowest tertile) compared to an OR of 1.4 (0.7, 2.9) for those diagnosed within 1–4 years of follow-up. No associations were observed with the other examined pro-inflammatory cytokines, IL1β, IL8 and TNFα.
Systemic plasma IL6 levels may inform long-term gastric cancer risk. This novel finding awaits confirmation in future studies with sequential plasma collection.
PMCID: PMC3349461  PMID: 21740481
cytokine; gastric cancer; prediagnostic
8.  B cell-stimulatory cytokines and markers of immune activation are elevated several years prior to the diagnosis of systemic AIDS-associated non-Hodgkin B cell lymphoma 
The risk of developing non-Hodgkin lymphoma (NHL) is greatly increased in HIV infection. The aim of this study was to determine if elevated serum levels of molecules associated with B cell activation precede the diagnosis of AIDS-associated NHL.
Serum levels of B cell activation-associated molecules, interleukin-6 (IL6), interleukin-10 (IL10), soluble CD23 (sCD23), soluble CD27 (sCD27), soluble CD30 (sCD30), C-reactive protein (CRP), and IgE were determined in 179 NHL cases and HIV+ controls in the Multicenter AIDS Cohort Study, collected at up to three time points per subject, 0–5 years prior to AIDS-NHL diagnosis.
Serum IL6, IL10, CRP, sCD23, sCD27, and sCD30 levels were all significantly elevated in the AIDS-NHL group, when compared to HIV+ controls or to AIDS controls, after adjusting for CD4 T cell number. Elevated serum levels of B cell activation-associated molecules were seen to be associated with the development of systemic (non-CNS) NHL, but not with the development of primary CNS lymphoma.
Levels of certain B cell stimulatory cytokines and molecules associated with immune activation are elevated for several years preceding the diagnosis of systemic AIDS-NHL. This observation is consistent with the hypothesis that chronic B cell activation contributes to the development of these hematologic malignancies.
Marked differences in serum levels of several molecules are seen for several years pre-diagnosis in those who eventually develop AIDS-NHL. Some of these molecules may serve as candidate biomarkers and provide valuable information to better define the etiology of NHL.
PMCID: PMC3132317  PMID: 21527584
lymphoma; B cell; cytokines; AIDS; immune activation
10.  An association between a variation in the PSCA gene and upper gastrointestinal cancer in Caucasians 
Gastroenterology  2010;140(2):435-441.
Background & Aims
An association between gastric cancer and the rs2294008 (C>T) polymorphism in the prostate stem cell antigen (PSCA) gene has been reported for several Asian populations. We set out to determine whether such an association exists in Caucasians.
We genotyped 166 relatives of gastric cancer patients, including 43 H pylori-infected subjects with hypochlorhydria and gastric atrophy, 65 infected subjects without these abnormalities, 58 H pylori-negative relatives, and 100 population controls. Additionally, a population-based study of chronic atrophic gastritis provided 533 cases and 1054 controls. We then genotyped 2 population-based case-control studies of upper gastrointestinal cancer: the first included 312 gastric cancer cases and 383 controls; the second included 309 gastric cancer cases, 159 esophageal cancer cases, and 211 controls. Odds ratios were computed from logistic models and adjusted for confounding variables.
Carriage of the risk allele (T) of rs2294008 in PSCA was associated with chronic atrophic gastritis (adjusted odds ratio [OR] = 1.5; 95% confidence interval [CI], 1.1–1.9) and non-cardia gastric cancer (OR = 1.9; 95% CI, 1.3– 2.8). The association was strongest for the diffuse histological-type (OR = 3.2; 95% CI, 1.2–10.7). An inverse association was observed between carriage of the risk allele and gastric cardia cancer (OR = 0.5; 95% CI, 0.3–0.9), esophageal adenocarcinoma (OR = 0.5; 95% CI, 0.3–0.9), and esophageal squamous cell carcinoma (OR = 0.4; 95% CI, 0.2–0.9).
The rs2294008 polymorphism in PSCA increases the risk of non-cardia gastric cancer and its precursors in Caucasians but protects against proximal cancers.
PMCID: PMC3031760  PMID: 21070776
Stomach cancer; esophageal cancer; genetic polymorphisms, cancer genetics
11.  Possible association between a genetic polymorphism at 8q24 and risk of upper gastrointestinal cancer 
Over recent years, genome wide association studies (GWAS) have contributed to our understanding of genetic susceptibility to sporadic cancer. In this study, we assessed the association between upper gastrointestinal cancer risk and four GWAS-identified single nucleotide polymorphisms (SNPs), previously implicated in prostate and colorectal cancer susceptibility. Genotyping for each SNP was performed in two, independent, Caucasian, population-based case-control studies. The first study comprised 290 gastric cancer cases and 374 controls. The second study included 185 non-cardia gastric cancers, 123 cardia cancers, 158 oesophageal cancers, and 209 controls. Odds ratios were computed from logistic models and adjusted for potential confounding variables. An inverse association was observed between the SNP rs1447295, located at 8q24, and gastric cancer risk in the first study population (odds ratio [OR] = 0.63; 95% Confidence Interval [CI], 0.41–0.97). A positive association was observed for the same SNP and oesophageal squamous cell carcinoma in the second study population (OR = 7.43; 95% CI, 1.37–49.98). No significant associations were detected in either study for the three remaining SNPs (rs6983297, rs10505477 and rs719725). Our data represent novel findings on heritable susceptibility to gastric and oesophageal cancer and warrant validation in additional populations.
PMCID: PMC3020097  PMID: 21102338
Gastric cancer; oesophageal cancer; genetic polymorphism; cancer susceptibiility
12.  Divergent trends for gastric cancer incidence by anatomical subsite in US adults 
Gut  2011;60(12):1644-1649.
Background and aim
Age-specific analyses of non-cardia gastric cancer incidence reveal divergent trends among US whites: rates are declining in individuals aged 40 years and older but rising in younger persons. To investigate this heterogeneity further, incidence trends were evaluated by anatomical subsite.
Gastric cancer incidence data for 1976–2007 were obtained from the US National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) Program and the US Centers for Disease Control and Prevention’s National Program of Cancer Registries (NPCR). Incidence rates and estimated annual percentage change were calculated by age group (25–39, 40–59 and 60–84 years), race/ethnicity and subsite.
Based on data from the nine oldest SEER registries (covering ~10% of the US population), rates for all non-cardia subsites decreased in whites and blacks, except for corpus cancer, which increased between 1976 and 2007 with estimated annual percentage changes of 1.0% (95% CI 0.1% to 1.9%) for whites and 3.5% (95% CI 1.8% to 5.2%) for blacks. In contrast, rates for all non-cardia subsites including corpus cancer declined among other races. In combined data from NPCR and SEER registries (covering 89% of the US population), corpus cancer significantly increased between 1999 and 2007 among younger and middle-aged whites; in ethnic-specific analyses, rates significantly increased among the same age groups in non-Hispanic whites and were stable among Hispanic whites. Age-specific rates for all subsites declined or were stable in this period among blacks and other races.
Long- and short-term incidence trends for gastric cancers indicate a shifting distribution by anatomical subsite. Corpus cancer may have distinctive aetiology and changing risk factor exposures, warranting further investigation.
PMCID: PMC3202077  PMID: 21613644
13.  Age-Specific Trends in Incidence of Noncardia Gastric Cancer in US Adults 
For the last 50 years, overall age-standardized incidence rates for noncardia gastric cancer have steadily declined in most populations. However, overall rates are summary measures that may obscure important age-specific trends.
To examine effects of age at diagnosis on noncardia gastric cancer incidence trends in the United States.
Design, Setting, and Participants
Descriptive study with age-period-cohort analysis of cancer registration data from the National Cancer Institute's Surveillance, Epidemiology, and End Results Program, which covers approximately 26% of the US population. From 1977 through 2006, there were 83 225 adults with incident primary gastric cancer, including 39 003 noncardia cases.
Main Outcome Measures
Overall and age-specific incidence rates, adjusted for period and cohort effects using age-period-cohort models. Results were stratified by race, sex, and socioeconomic status.
Overall age-standardized annual incidence per 100 000 population declined during the study period from 5.9 (95% confidence interval [CI], 5.7-6.1) to 4.0 (95% CI, 3.9-4.1) in whites, from 13.7 (95% CI, 12.5-14.9) to 9.5 (95% CI, 9.1-10.0) in blacks, and from 17.8 (95% CI, 16.1-19.4) to 11.7 (95% CI, 11.2-12.1) in other races. Age-specific trends among whites varied significantly between older and younger age groups (P < .001 for interaction by age): incidence per 100 000 declined significantly from 19.8 (95% CI, 19.0-20.6) to 12.8 (95% CI, 12.5-13.1) for ages 60 to 84 years and from 2.6 (95% CI, 2.4-2.8) to 2.0 (95% CI, 1.9-2.1) for ages 40 to 59 years but increased significantly from 0.27 (95% CI, 0.19-0.35) to 0.45 (95% CI, 0.39-0.50) for ages 25 to 39 years. Conversely, rates for all age groups declined or were stable among blacks and other races. Age-period-cohort analysis confirmed a significant increase in whites among younger cohorts born since 1952 (P < .001).
From 1977 through 2006, the incidence rate for noncardia gastric cancer declined among all race and age groups except for whites aged 25 to 39 years, for whom it increased. Additional surveillance and analytical studies are warranted to identify risk factors that may explain this unfavorable trend.
PMCID: PMC3142962  PMID: 20442388
14.  Kaposi Sarcoma-Associated Herpesvirus Serum DNA and Antibodies Not Associated With Subsequent Non-Hodgkin Lymphoma Risk 
Kaposi sarcoma-associated herpes virus (KSHV) infects B-cells and is found in non-Hodgkin lymphoma (NHL) B-cell tumors and could therefore contribute to the occurrence of NHL. We performed a nested case–control study including 155 incident NHL cases and matched noncancer controls. Pre-NHL serum was tested for KSHV DNA and antibodies. Serum KSHV DNA was more common in cases than controls (14% versus 6%, P = 0.03), but after adjustment, the difference was not significant. Epstein-Barr virus serum DNA was similarly unassociated with NHL as were KSHV antibodies. KSHV is not a primary cause of NHL in HIV-infected men who have sex with men.
PMCID: PMC3073851  PMID: 21116187
Kaposi sarcoma-associated herpesvirusp; non-Hodgkin lymphoma; MACS; human herpesvirus 8; DNA; AIDS cancer
15.  Circulating Serum Free Light Chains As Predictive Markers of AIDS-Related Lymphoma 
Journal of Clinical Oncology  2010;28(5):773-779.
HIV-infected persons have an elevated risk of developing non-Hodgkin's lymphoma (NHL); this risk remains increased in the era of effective HIV therapy. We evaluated serum immunoglobulin (Ig) proteins as predictors of NHL risk among HIV-infected individuals.
Patients and Methods
By using three cohorts of HIV-infected persons (from 1982 to 2005), we identified 66 individuals who developed NHL and 225 matched (by cohort, sex, ethnicity, age, and CD4 count), HIV-infected, lymphoma-free controls who had available stored prediagnostic blood samples. Serum/plasma samples obtained 0 to 2 years and 2 to 5 years before diagnosis/selection were assayed for IgG, IgM, and IgA levels; monoclonal (M) Igs; and κ and λ free light chain (FLC) levels. Patients and matched controls were compared by using conditional logistic regression.
The κ and λ FLCs were both significantly higher in patients (eg, in 2- to 5-year window: median κ, 4.24 v 3.43 mg/dL; median λ, 4.04 v 3.09 mg/dL) and strongly predicted NHL in a dose-response manner up to 2 to 5 years before diagnosis/selection (eg, NHL risk 3.76-fold higher with κ concentration at least 2.00 times the upper limit of normal, and 8.13-fold higher with λ concentration at least 2.00 times the upper limit of normal compared with normal levels). In contrast, IgG, IgM, and IgA levels were similar in patients and controls. M proteins were detected in only two patients with NHL (3%) and in nine controls (4%), and they were not significantly associated with NHL risk.
Elevated FLCs may represent sensitive markers of polyclonal B-cell activation and dysfunction and could be useful for identifying HIV-infected persons at increased NHL risk.
PMCID: PMC2834393  PMID: 20048176
16.  The Major Histocompatibility Complex Conserved Extended Haplotype 8.1 in AIDS-related Non-Hodgkin’s Lymphoma 
Two single nucleotide polymorphisms (SNPs) in adjacent genes, lymphotoxin alpha (LTA +252G, rs909253 A>G) and tumor necrosis factor (TNF −308A, rs1800629 G>A), form the G-A haplotype repeatedly associated with increased risk of non-Hodgkin’s lymphoma (NHL) in individuals uninfected with HIV-1. This association has been observed alone or in combination with HLA-B* 08 or HLA-DRB1*03 in the major histocompatibility complex (MHC). Which gene variant on this highly conserved extended haplotype (CEH 8.1) in Caucasians most likely represents a true etiologic factor remains uncertain. We aimed to determine whether the reported association of the G-A haplotype of LTA-TNF with non-AIDS NHL also occurs with AIDS-related NHL. SNPs in LTA and TNF and in six other genes nearby were typed in 140 non-Hispanic European American pairs of AIDS-NHL cases and matched controls selected from HIV-infected men in the Multicenter AIDS Cohort Study. The G-A haplotype and a 4-SNP haplotype in the neighboring gene cluster (rs537160 (A) rs1270942 (G), rs2072633 (A) and rs6467 (C)) were associated with AIDS-NHL (OR=2.7, 95% CI: 1.5–4.8, p=0.0009 and OR=3.2, 95% CI: 1.6–6.6 p=0.0008; respectively). These two haplotypes occur in strong linkage disequilibrium with each other on CEH 8.1. The CEH 8.1-specific haplotype association of MHC class III variants with AIDS-NHL closely resembles that observed for non-AIDS NHL. Corroboration of an MHC determinant of AIDS and non-AIDS NHL alike would imply an important pathogenetic mechanism common to both.
PMCID: PMC3015185  PMID: 19654554
Human Leukocyte Antigen; HIV; CD4; Multicenter AIDS Cohort NHL Study
17.  CD14-159C/T and TLR9-1237T/C polymorphisms are not associated with gastric cancer risk in Caucasian populations 
Host genetic factors play an important role in modifying the risk of human disease, including cancers of the upper gastrointestinal tract, with increasing interest in Toll-like receptor (TLR) signaling and the impact of genetic polymorphisms in these systems. The CD14-159C/T and the TLR9-1237T/C promoter polymorphisms have previously been shown to be associated with various inflammatory conditions including Helicobacter pylori-induced gastritis in Caucasian populations. In this study, we assessed the association of these two functional single nucleotide polymorphisms with gastric cancer in two independent Caucasian population-based case–control studies of upper gastrointestinal tract cancer, initially in 312 noncardia gastric carcinoma cases and 419 controls and then in 184 noncardia gastric carcinomas, 123 cardia carcinomas, 159 esophageal cancers, and 211 frequency-matched controls. Odds ratios were computed from logistic models and adjusted for potential confounding factors. No significant association was found between the CD14-159C/T and the TLR9-1237T/C promoter polymorphisms and increased risk of gastric cancer. Neither single nucleotide polymorphism has been assessed in a Caucasian gastric cancer case–control study before; although the CD14-159C/T polymorphism has been reported to show no apparent association with H. pylori-related gastric malignancy in a Taiwanese Chinese population. In conclusion, although our earlier preliminary studies suggested that the CD14-159C/T and the TLR9-1237T/C promoter polymorphisms increase the risk of precancerous outcomes, they do not seem to increase the risk of gastric cancer itself. This discrepancy merits further examination.
PMCID: PMC2679029  PMID: 19337058
gastric cancer; Helicobacter pylori-induced disease; innate immunity; polymorphisms; Toll-like receptor signaling pathways
18.  Foreskin inflammation is associated with HIV and herpes simplex virus type-2 infections in Rakai, Uganda 
AIDS (London, England)  2009;23(14):1807-1815.
We assessed foreskin inflammation associated with HIV and herpes simplex virus type 2 (HSV-2) in circumcised men.
Foreskin tissues were assessed in 97 HIV-infected and 135 HIV-uninfected men enrolled in randomized trials of circumcision in Rakai, Uganda. Inflammation was quantified using an ordinal score evaluating extent, intensity, and cellular composition of infiltrates in the epithelium and stroma. Prevalence rate ratios of inflammation were estimated by multivariate Poisson regression.
Foreskin inflammation was primarily focal. Epithelial inflammation was present in 4.2% of men with neither HIV nor HSV-2 infection; 7.8% of men with only HSV-2; 19.0% with HIV alone (P=0.04); and 31.6% in HIV/HSV-2 coinfected men [prevalence rate ratio (PRR) 7.5, 95% confidence interval (CI) 2.3-23.8, P<0.001]. Stromal inflammation was present in 14.1% of HIV/HSV-2 uninfected men, compared with 29.7% in men with HSV-2 alone (P=0.03), 33.3% in men with HIV alone (P=0.04), and 61.0% in men with HIV/HSV-2 coinfection (PRR 4.3, 95% CI 2.3-7.9, P<0.001). In HIV-infected men, epithelial inflammation was associated with higher HIV viral load. Epithelial inflammation was more frequent among men reporting recent genital ulceration. Both epithelial and stromal inflammation were more common among men with smegma on physical examination.
Foreskin inflammation is increased with HIV and HSV-2 infections, higher HIV viral load and presence of smegma. Foreskin inflammation may have implications for HIV transmission and acquisition in uncircumcised men.
PMCID: PMC2752438  PMID: 19584700
circumcision; foreskin; HIV; herpes simplex virus type 2; inflammation; Uganda
19.  Sexually Transmissible Infections and Prostate Cancer Risk 
Sexually transmissible infections (STIs) have been variably associated with increased risks of prostate cancer, largely in case-control studies.
In the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial, we examined risk of prostate cancer in relation to serum antibodies to Chlamydia trachomatis, human papillomavirus (HPV) types 16 and 18, herpes simplex virus (HSV) type 2, cytomegalovirus (CMV), and human herpesvirus 8 (HHV-8) in 868 cases (765 whites and 103 blacks) and 1,283 controls matched by race, age, time since initial screening, and year of blood draw; all blood samples were collected at least one year prior to prostate cancer diagnosis, except for 43 black cases. We also assessed risk associated with self-reported history of syphilis and gonorrhea.
Prevalences of the 7 STIs among controls were weakly correlated, and all were more frequent among blacks than whites, except for HHV-8. Among whites, prostate cancer risk was not significantly associated with the individual infections nor with their number (Ptrend = 0.1); however, men with one or more STI had slightly higher risk (odds ratio [OR] = 1.3, 95% confidence interval [CI] = 1.0-1.6). Among blacks, excess risk was associated with IgA antibody to C. trachomatis (OR = 2.1, 95% CI = 1.2-3.6).
This large prospective study of prostate cancer shows no consistent association with specific STIs and a borderline association with any vs. none. Whether a shared response or correlated infection not directly measured underlies the weak association requires further study.
PMCID: PMC2559953  PMID: 18768506
20.  Genetic Variants in T Helper Cell Type 1, 2 and 3 Pathways and Gastric Cancer Risk in a Polish Population 
Host immune responses are known determinants of gastric cancer susceptibility. We previously reported an increased gastric cancer risk associated with common variants of several T helper type 1 (Th1) cytokine genes in a population-based case–control study in Warsaw, Poland. In the present study, we augmented our investigation to include additional Th1 genes as well as key genes in the Th2 and Th3 pathways. Analysis of 378 cases and 435 age- and sex-matched controls revealed associations for polymorphisms in the Th1 IL7R gene and one polymorphism in the Th2 IL5 gene. The odd ratios (ORs) for IL7R rs1494555 were 1.4 [95% confidence interval (CI), 1.0–1.9] for A/G and 1.5 (95% CI, 1.0–2.4) for G/G carriers relative to A/A carriers (P = 0.04). The ORs for IL5 rs2069812 were 0.9 (95% CI, 0.7–1.3) for C/T and 0.6 (95% CI, 0.3–1.0) T/T carriers compared with C/C carriers (P = 0.03). These results suggest that IL5 rs2069812 and IL7R rs1389832, rs1494556 and rs1494555 polymorphisms may contribute to gastric cancer etiology.
PMCID: PMC2528891  PMID: 18687755
gastric cancer; T helper cell pathways; polymorphism
21.  Mechanisms and Consequences of Chromosomal Translocation 
A 2006 National Cancer Institute workshop on chromosomal translocations brought together laboratory, clinical, and population scientists to cross-fertilize and catalyze research on this important disease process. The deliberations revealed significant contrasts between two types of translocations that result in either deregulated expression of oncogenes or formation of novel fusion genes. The oncogene-activating MYC-IGH exchange is the best-elucidated translocation in terms of molecular structure and functional consequences and the anti-apoptotic effects of constitutively activated BCL2 facilitate the detection of the BCL2-IGH translocation in blood as a potential predictor of cancer risk. In comparison, the fusion-gene translocations such as BCR-ABL and the varied recombinations of MLL have well-described clinical manifestations but are less well-defined with regard to their mechanisms of generation. Interdisciplinary collaboration on chromosomal translocations should yield additional insights regarding their biologic significance and potential as targets for intervention.
PMCID: PMC2562255  PMID: 18708370
chromosome; translocation; oncogene; fusion-gene; meeting report
22.  Human herpesvirus 8 load and progression of AIDS-related Kaposi sarcoma lesions 
Cancer letters  2008;263(2):182-188.
Human herpesvirus 8 (HHV8) is necessary for Kaposi sarcoma (KS) to develop, but whether peripheral blood viral load is a marker of KS burden (total number of KS lesions), KS progression (the rate of eruption of new KS lesions), or both is unclear. We investigated these relationships in persons with AIDS.
Newly diagnosed patients with AIDS-related KS attending Mulago Hospital, in Kampala, Uganda, were assessed for KS burden and progression by questionnaire and medical examination. Venous blood samples were taken for HHV8 load measurements by PCR. Associations were examined with odds ratio (OR) and 95% confidence intervals (CI) from logistic regression models and with t-tests.
Among 74 patients (59% men), median age was 34.5 years (interquartile range [IQR], 28.5-41). HHV8 DNA was detected in 93% and quantified in 77% patients. Median virus load was 3.8 logs10/106 peripheral blood cells (IQR 3.4-5.0) and was higher in men than women (4.4 vs. 3.8 logs; p=0.04), in patients with faster (>20 lesions per year) than slower rate of KS lesion eruption (4.5 vs. 3.6 logs; p<0.001), and higher, but not significantly, among patients with more (>median [20] KS lesions) than fewer KS lesions (4.4 vs. 4.0 logs; p=0.16). HHV8 load was unrelated to CD4 lymphocyte count (p=0.23).
We show significant association of HHV8 load in peripheral blood with rate of eruption of KS lesions, but not with total lesion count. Our results suggest that viral load increases concurrently with development of new KS lesions.
PMCID: PMC2440724  PMID: 18234418
Africa; epidemiology
23.  Hematotoxicity in Workers Exposed to Low Levels of Benzene 
Science (New York, N.Y.)  2004;306(5702):1774-1776.
Benzene is known to have toxic effects on the blood and bone marrow, but its impact at levels below the U.S. occupational standard of 1 part per million (ppm) remains uncertain. In a study of 250 workers exposed to benzene, white blood cell and platelet counts were significantly lower than in 140 controls, even for exposure below 1 ppm in air. Progenitor cell colony formation significantly declined with increasing benzene exposure and was more sensitive to the effects of benzene than was the number of mature blood cells. Two genetic variants in key metabolizing enzymes, myeloperoxidase and NAD(P)H:quinone oxidoreductase, influenced susceptibility to benzene hematotoxicity. Thus, hematotoxicity from exposure to benzene occurred at air levels of 1 ppm or less and may be particularly evident among genetically susceptible subpopulations.
PMCID: PMC1256034  PMID: 15576619
24.  High-Level Variability in the ORF-K1 Membrane Protein Gene at the Left End of the Kaposi’s Sarcoma-Associated Herpesvirus Genome Defines Four Major Virus Subtypes and Multiple Variants or Clades in Different Human Populations 
Journal of Virology  1999;73(5):4156-4170.
Infection with Kaposi’s sarcoma (KS)-associated herpesvirus (KSHV) or human herpesvirus 8 (HHV8) is common in certain parts of Africa, the Middle East, and the Mediterranean, but is rare elsewhere, except in AIDS patients. Nevertheless, HHV8 DNA is found consistently in nearly all classical, endemic, transplant and AIDS-associated KS lesions as well as in some rare AIDS-associated lymphomas. The concept that HHV8 genomes fall into several distinct subgroups has been confirmed and refined by PCR DNA sequence analysis of the ORF-K1 gene encoding a highly variable glycoprotein related to the immunoglobulin receptor family that maps at the extreme left-hand end of the HHV-8 genome. Among more than 60 different tumor samples from the United States, central Africa, Saudi Arabia, Taiwan, and New Zealand, amino acid substitutions were found at a total of 62% of the 289 amino acid positions. These variations defined four major subtypes and 13 distinct variants or clades similar to those found for the HIV ENV protein. The B and D subtype ORF-K1 proteins differ from the A and C subtypes by 30 and 24%, respectively, whereas A and C differ from each other by 15%. In all cases tested, multiple samples from the same patient were identical. Examples of the B subtype were found almost exclusively in KS patients from Africa or of African heritage, whereas the rare D subtypes were found only in KS patients of Pacific Island heritage. In contrast, C subtypes were found predominantly in classic KS and in iatrogenic and AIDS KS in the Middle East and Asia, whereas U.S. AIDS KS samples were primarily A1, A4, and C3 variants. We conclude that this unusually high diversity, in which 85% of the nucleotide changes lead to amino acid changes, reflects some unknown powerful biological selection process that has been acting preferentially on this early lytic cycle membrane signalling protein. Two distinct levels of ORF-K1 variability are recognizable. Subtype-specific variability indicative of long-term evolutionary divergence is both spread throughout the protein as well as concentrated within two 40-amino-acid extracellular domain variable regions (VR1 and VR2), whereas intratypic variability localizes predominantly within a single 25-amino-acid hypervariable Cys bridge loop and apparently represents much more recent changes that have occurred even within specific clades. In contrast, numerous extracellular domain glycosylation sites and Cys bridge residues as well as the ITAM motif in the cytoplasmic domain are fully conserved. Overall, we suggest that rather than being a newly acquired human pathogen, HHV8 is an ancient human virus that is preferentially transmitted in a familial fashion and is difficult to transmit horizontally in the absence of immunosuppression. The division into the four major HHV8 subgroups is probably the result of isolation and founder effects associated with the history of migration of modern human populations out of Africa over the past 35,000 to 60,000 years.
PMCID: PMC104195  PMID: 10196312

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