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1.  Genome-wide association study and meta-analysis of intraocular pressure 
Human genetics  2013;133(1):41-57.
Elevated intraocular pressure (IOP) is a major risk factor for glaucoma and is influenced by genetic and environmental factors. Recent genome-wide association studies (GWAS) reported associations with IOP at TMCO1 and GAS7, and with primary open-angle glaucoma (POAG) at CDKN2B-AS1, CAV1/CAV2, and SIX1/SIX6. To identify novel genetic variants and replicate the published findings, we performed GWAS and meta-analysis of IOP in >6,000 subjects of European ancestry collected in three datasets: the NEI Glaucoma Human genetics collaBORation, GLAUcoma Genes and ENvironment study, and a subset of the Age-related Macular Degeneration-Michigan, Mayo, AREDS and Pennsylvania study. While no signal achieved genome-wide significance in individual datasets, a meta-analysis identified significant associations with IOP at TMCO1 (rs7518099-G, p = 8.0 × 10−8). Focused analyses of five loci previously reported for IOP and/or POAG, i.e., TMCO1, CDKN2B-AS1, GAS7, CAV1/CAV2, and SIX1/SIX6, revealed associations with IOP that were largely consistent across our three datasets, and replicated the previously reported associations in both effect size and direction. These results confirm the involvement of common variants in multiple genomic regions in regulating IOP and/or glaucoma risk.
PMCID: PMC3982323  PMID: 24002674
2.  Hypomethylation of the IL17RC Promoter in Peripheral Blood Leukocytes is Not A Hallmark of Age-Related Macular Degeneration 
Cell reports  2013;5(6):1527-1535.
Age-related macular degeneration (AMD) is a leading cause of visual impairment worldwide. Aberrant DNA methylation within the promoter of IL17RC in peripheral blood mononuclear cells has recently been reported in AMD. To validate this association, we examined DNA methylation of the IL17RC promoter in peripheral blood. First, we used Illumina Human Methylation450 Bead Arrays, a widely-accepted platform for measuring global DNA methylation. Second, methylation status at multiple sites within the IL17RC promoter was determined by bisulfite pyrosequencing in two cohorts. Third, a methylation-sensitive QPCR-based assay was performed on a subset of samples. In contrast to previous findings, we did not find evidence of differential methylation between AMD cases and age-matched controls. We conclude that hypomethylation within the IL17RC gene promoter in peripheral blood is not suitable for use as a clinical biomarker of AMD. This study highlights the need for considerable replication of epigenetic association studies prior to clinical application.
PMCID: PMC3926096  PMID: 24373284
3.  Identification of a Rare Coding Variant in Complement 3 Associated with Age-related Macular Degeneration 
Nature genetics  2013;45(11):10.1038/ng.2758.
Macular degeneration is a common cause of blindness in the elderly. To identify rare coding variants associated with a large increase in risk of age-related macular degeneration (AMD), we sequenced 2,335 cases and 789 controls in 10 candidate loci (57 genes). To increase power, we augmented our control set with ancestry-matched exome sequenced controls. An analysis of coding variation in 2,268 AMD cases and 2,268 ancestry matched controls revealed two large-effect rare variants; previously described R1210C in the CFH gene (fcase = 0.51%, fcontrol = 0.02%, OR = 23.11), and newly identified K155Q in the C3 gene (fcase = 1.06%, fcontrol = 0.39%, OR = 2.68). The variants suggest decreased inhibition of C3 by Factor H, resulting in increased activation of the alternative complement pathway, as a key component of disease biology.
PMCID: PMC3812337  PMID: 24036949
4.  Solid pseudopapillary neoplasm of the pancreas with prominent atypical multinucleated giant tumor cells 
Histopathology  2012;62(3):465-471.
Solid pseudopapillary neoplasm of the pancreas (SPN) is a rare low-grade malignant neoplasm. SPN with prominent atypical multinucleated giant tumor cells (MNGTCs) has not been reported.
Methods and results
We identified four cases of SPN with prominent atypical MNGTCs in a cohort of 62 cases of SPN (6.5%). The MNGTCs contained multiple enlarged, hyperchromatic, irregular nuclei with ample eosinophilic cytoplasm, typically present in the solid area of the tumor. The MNGTCs had a typical immunohistochemical profile of the conventional SPN and were positive for vimentin, β-catenin, CD10, and progesterone receptor, but were negative for pan-cytokeratin chromogranin, synaptophysin, trypsin, Ki-67 and CD68 in all four cases. Patients of SPN with prominent MNGTCs were older than those with conventional SPN (p=0.01), tumors were incidentally discovered by imaging studies for an unrelated disease in all four cases, and with a female to male ratio of 1:1. The proliferation index (Ki-67) was <1% in all four cases. None of the three patients, whose follow up information was available, developed recurrence during follow-up of 2.7, 3.8 and 5.0 years.
The presence of MNGTCs in SPN most likely represents degenerative change of the tumor cells and does not seem to affect the prognosis.
PMCID: PMC3553313  PMID: 23134473
solid pseudopapillary neoplasm; multinucleated giant cells; prognosis
5.  Mutations in RPGR and RP2 Account for 15% of Males with Simplex Retinal Degenerative Disease 
To determine the proportion of male patients presenting simplex retinal degenerative disease (RD: retinitis pigmentosa [RP] or cone/cone-rod dystrophy [COD/CORD]) with mutations in the X-linked retinal degeneration genes RPGR and RP2.
Simplex males were defined as patients with no known affected family members. Patients were excluded if they had a family history of parental consanguinity. Blood samples from a total of 214 simplex males with a diagnosis of retinal degeneration were collected for genetic analysis. The patients were screened for mutations in RPGR and RP2 by direct sequencing of PCR-amplified genomic DNA.
We identified pathogenic mutations in 32 of the 214 patients screened (15%). Of the 29 patients with a diagnosis of COD/CORD, four mutations were identified in the ORF15 mutational hotspot of the RPGR gene. Of the 185 RP patients, three patients had mutations in RP2 and 25 had RPGR mutations (including 12 in the ORF15 region).
This study represents mutation screening of RPGR and RP2 in the largest cohort, to date, of simplex males affected with RP or COD/CORD. Our results demonstrate a substantial contribution of RPGR mutations to retinal degenerations, and in particular, to simplex RP. Based on our findings, we suggest that RPGR should be considered as a first tier gene for screening isolated males with retinal degeneration.
Identification of mutations in 15% of the screened patients has important implications for guiding clinicians who are ordering genetic testing and provides a strong argument for screening the RPGR gene in simplex cases of retinal degenerative diseases.
PMCID: PMC3522443  PMID: 23150612
6.  Global expression profiling of peripheral Qa-1-restricted CD8αα+TCRαβ+ regulatory T Cells reveals innate-like features: implications for immune regulatory repertoire 
Human Immunology  2011;73(3):214-222.
Among peripheral regulatory T cells, CD8+ T cells also play an important role in the maintenance of immune homeostasis. A subset of CD8+ Treg that express αβTCR and CD8αα homodimers can recognize TCR-derived peptides in the context of the class Ib MHC molecule Qa-1. To gain a better understanding of the nature and phenotype of CD8αα+TCRαβ+ Treg, a global gene expression profiling using microarray, real-time quantitative PCR, and flowcytometry analysis was performed using functional Treg clones and lines. Our data show that CD8+ Treg shared gene profile expressed by innate-like lymphocytes, including murine intraepithelial lymphocytes and thymic CD8αα+TCRαβ+ T cell populations. Additionally, this subset displays differential expression of several key regulatory molecules, including CD200. CD8αα+ Treg expressed higher levels of a number of NK cell related receptors and molecules belonging to the TNF superfamily. Collectively, peripheral class Ib-reactive CD8αα+TCRαβ+ T cells represent a unique regulatory population different from class Ia MHC-restricted conventional T cells. These studies have important implications for the regulatory mechanisms mediated by the CD8+ Treg population in general.
PMCID: PMC3261310  PMID: 21889557
CD8+ Treg; EAE; Microarray; Innate cells; Qa-1/HLA-E
7.  Renal artery embolization for managing uncontrolled hypertension in a kidney transplant candidate 
Avicenna Journal of Medicine  2013;3(1):23-25.
We report a case of pre-operative bilateral renal artery embolization to control the resistant and malignant hypertension in a patient prepared for kidney transplantation. A 34-year-old man with end-stage renal disease as a result of the focal segmental glomerulosclerosis and uncontrolled hypertension that precluded the transplantation surgery and the patient's post-transplant blood pressure and the renal function remained within normal limits following the transplant for 6 months of follow-up.
PMCID: PMC3752858  PMID: 23984264
Kidney transplant; malignant hypertension; renal artery embolization
8.  Evidence of association of APOE with age-related macular degeneration - a pooled analysis of 15 studies 
Human mutation  2011;32(12):1407-1416.
Age-related macular degeneration (AMD) is the most common cause of incurable visual impairment in high-income countries. Previous studies report inconsistent associations between AMD and apolipoprotein E (APOE), a lipid transport protein involved in low-density cholesterol modulation. Potential interaction between APOE and sex, and smoking status, has been reported. We present a pooled analysis (n=21,160) demonstrating associations between late AMD and APOε4 (OR=0.72 per haplotype; CI: 0.65–0.74; P=4.41×10−11) and APOε2 (OR=1.83 for homozygote carriers; CI: 1.04–3.23; P=0.04), following adjustment for age-group and sex within each study and smoking status. No evidence of interaction between APOE and sex or smoking was found. Ever smokers had significant increased risk relative to never smokers for both neovascular (OR=1.54; CI: 1.38–1.72; P=2.8×10−15) and atrophic (OR=1.38; CI: 1.18–1.61; P=3.37×10−5) AMD but not early AMD (OR=0.94; CI: 0.86–1.03; P=0.16), implicating smoking as a major contributing factor to disease progression from early signs to the visually disabling late forms. Extended haplotype analysis incorporating rs405509 did not identify additional risks beyondε2 and ε4 haplotypes. Our expanded analysis substantially improves our understanding of the association between the APOE locus and AMD. It further provides evidence supporting the role of cholesterol modulation, and low-density cholesterol specifically, in AMD disease etiology.
PMCID: PMC3217135  PMID: 21882290
age-related macular degeneration; AMD; apolipoprotein E; APOE; case-control association study
Archives of Ophthalmology  2010;128(7):915-923.
To assess the phenotype of X-linked retinitis pigmentosa (XLRP) patients with RP2 mutations and correlate the findings with their genotype.
Clinical Relevance
An identifiable phenotype for RP2-XLRP aids in clinical diagnosis and targeted genetic screening.
Over 600 XLRP patients and carriers were screened during a ten-year period for mutations in the RP2 gene. Twenty-five RP2 patients were evaluated clinically with standardized electroretinography (ERG), Goldmann visual fields, and ocular examinationsl. In addition, well documented cases from the literature were used to augment genotype-phenotype correlations.
In our male cohort under the age of 12 years: 10/11 (91%) patients had macular involvement and 10/11 (91%) had best corrected visual acuities worse than 20/50. Two males from different families (ages 8 and 12) displayed a choroideremia-like fundus, and 9/11( 82%) of male patients were myopic with a mean error of −7.97D. Of patients with ERG data, 9/10 (90%) demonstrated severe rod-cone dysfunction. All three female carriers had macular atrophy in one or both eyes and were myopic (mean −6.23 D). We identified four novel RP2 mutations. All nine nonsense and five of seven missense mutations (71%) resulted in severe clinical presentations.
Screening of the RP2 gene should be prioritized in patients less than 16 years of age characterized by X-linked inheritance, decreased BCVA (e.g.,>20/40), high myopia, and early-onset macular atrophy. We also suggest that patients exhibiting a choroideremia-like fundus appearance who do not have disease-causing mutations in the choroideremia gene (CHM) be screened for variations in RP2. We believe that alterations in function play a significant role in RP2-associated disease pathogenesis.
PMCID: PMC3392190  PMID: 20625056
10.  Variations in Apolipoprotein E Frequency With Age in a Pooled Analysis of a Large Group of Older People 
American Journal of Epidemiology  2011;173(12):1357-1364.
Variation in the apolipoprotein E gene (APOE) has been reported to be associated with longevity in humans. The authors assessed the allelic distribution of APOE isoforms ε2, ε3, and ε4 among 10,623 participants from 15 case-control and cohort studies of age-related macular degeneration (AMD) in populations of European ancestry (study dates ranged from 1990 to 2009). The authors included only the 10,623 control subjects from these studies who were classified as having no evidence of AMD, since variation within the APOE gene has previously been associated with AMD. In an analysis stratified by study center, gender, and smoking status, there was a decreasing frequency of the APOE ε4 isoform with increasing age (χ2 for trend = 14.9 (1 df); P = 0.0001), with a concomitant increase in the ε3 isoform (χ2 for trend = 11.3 (1 df); P = 0.001). The association with age was strongest in ε4 homozygotes; the frequency of ε4 homozygosity decreased from 2.7% for participants aged 60 years or less to 0.8% for those over age 85 years, while the proportion of participants with the ε3/ε4 genotype decreased from 26.8% to 17.5% across the same age range. Gender had no significant effect on the isoform frequencies. This study provides strong support for an association of the APOE gene with human longevity.
PMCID: PMC3145394  PMID: 21498624
aged; apolipoprotein E2; apolipoprotein E3; apolipoprotein E4; apolipoproteins E; longevity; meta-analysis; multicenter study
11.  Complement Factor D in Age-Related Macular Degeneration 
Complement factor D catalyzes a critical step in the alternative complement activation pathway. The authors report a significant elevation in plasma CFD concentrations in age-related macular degeneration (AMD) patients compared with controls and a weak genetic association between CFD gene variants and AMD.
To examine the role of complement factor D (CFD) in age-related macular degeneration (AMD) by analysis of genetic association, copy number variation, and plasma CFD concentrations.
Single nucleotide polymorphisms (SNPs) in the CFD gene were genotyped and the results analyzed by binary logistic regression. CFD gene copy number was analyzed by gene copy number assay. Plasma CFD was measured by an enzyme-linked immunosorbent assay.
Genetic association was found between CFD gene SNP rs3826945 and AMD (odds ratio 1.44; P = 0.028) in a small discovery case-control series (462 cases and 325 controls) and replicated in a combined cohorts meta-analysis of 4765 cases and 2693 controls, with an odds ratio of 1.11 (P = 0.032), with the association almost confined to females. Copy number variation in the CFD gene was identified in 13 out of 640 samples examined but there was no difference in frequency between AMD cases (1.3%) and controls (2.7%). Plasma CFD concentration was measured in 751 AMD cases and 474 controls and found to be elevated in AMD cases (P = 0.00025). The odds ratio for those in the highest versus lowest quartile for plasma CFD was 1.81. The difference in plasma CFD was again almost confined to females.
CFD regulates activation of the alternative complement pathway, which is implicated in AMD pathogenesis. The authors found evidence for genetic association between a CFD gene SNP and AMD and a significant increase in plasma CFD concentration in AMD cases compared with controls, consistent with a role for CFD in AMD pathogenesis.
PMCID: PMC3230905  PMID: 22003108
12.  Rd9 Is a Naturally Occurring Mouse Model of a Common Form of Retinitis Pigmentosa Caused by Mutations in RPGR-ORF15 
PLoS ONE  2012;7(5):e35865.
Animal models of human disease are an invaluable component of studies aimed at understanding disease pathogenesis and therapeutic possibilities. Mutations in the gene encoding retinitis pigmentosa GTPase regulator (RPGR) are the most common cause of X-linked retinitis pigmentosa (XLRP) and are estimated to cause 20% of all retinal dystrophy cases. A majority of RPGR mutations are present in ORF15, the purine-rich terminal exon of the predominant splice-variant expressed in retina. Here we describe the genetic and phenotypic characterization of the retinal degeneration 9 (Rd9) strain of mice, a naturally occurring animal model of XLRP. Rd9 mice were found to carry a 32-base-pair duplication within ORF15 that causes a shift in the reading frame that introduces a premature-stop codon. Rpgr ORF15 transcripts, but not protein, were detected in retinas from Rd9/Y male mice that exhibited retinal pathology, including pigment loss and slowly progressing decrease in outer nuclear layer thickness. The levels of rhodopsin and transducin in rod outer segments were also decreased, and M-cone opsin appeared mislocalized within cone photoreceptors. In addition, electroretinogram (ERG) a- and b-wave amplitudes of both Rd9/Y male and Rd9/Rd9 female mice showed moderate gradual reduction that continued to 24 months of age. The presence of multiple retinal features that correlate with findings in individuals with XLRP identifies Rd9 as a valuable model for use in gaining insight into ORF15-associated disease progression and pathogenesis, as well as accelerating the development and testing of therapeutic strategies for this common form of retinal dystrophy.
PMCID: PMC3341386  PMID: 22563472
13.  Evaluation of Trace Metal Levels in Tissues of Two Commercial Fish Species in Kapar and Mersing Coastal Waters, Peninsular Malaysia 
This study is focused on evaluating the trace metal levels in water and tissues of two commercial fish species Arius thalassinus and Pennahia anea that were collected from Kapar and Mersing coastal waters. The concentrations of Fe, Zn, Al, As, Cd and Pb in these coastal waters and muscle, liver and gills tissues of the fishes were quantified. The relationship among the metal concentrations and the height and weight of the two species were also examined. Generally, the iron has the highest concentrations in both water and the fish species. However, Cd in both coastal waters showed high levels exceeding the international standards. The metal level concentration in the sample fishes are in the descending order livers > gills > muscles. A positive association between the trace metal concentrations and weight and length of the sample fishes was investigated. Fortunately the level of these metal concentrations in fish has not exceeded the permitted level of Malaysian and international standards.
PMCID: PMC3199202  PMID: 22046193
14.  Toxicity of Metals to a Freshwater Ostracod: Stenocypris major 
Journal of Toxicology  2011;2011:136104.
Adults of freshwater ostracod Stenocypris major (Crustacea, Candonidae) were exposed for a four-day period in laboratory conditions to a range of copper (Cu), cadmium (Cd), zinc (Zn), lead (Pb), nickel (Ni), iron (Fe), aluminium (Al), and manganese (Mn) concentrations. Mortality was assessed, and median lethal times (LT50) and concentrations (LC50) were calculated. LT50 and LC50 increased with the decrease in mean exposure concentrations and times, respectively, for all metals. LC50s for 96 hours for Cu, Cd, Zn, Pb, Ni, Fe, Al, and Mn were 25.2, 13.1, 1189.8, 526.2, 19743.7, 278.9, 3101.9, and 510.2 μg/L, respectively. Metals bioconcentration in S. major increases with exposure to increasing concentrations, and Cd was the most toxic to S. major, followed by Cu, Fe, Mn, Pb, Zn, Al, and Ni (Cd>Cu>Fe>Mn>Pb>Zn>Al>Ni). Comparison of LC50 values for metals for this species with those for other freshwater crustacean reveals that S. major is equally or more sensitive to metals than most other tested crustacean.
PMCID: PMC3090608  PMID: 21559091
15.  Cardiac beriberi: morphological findings in two fatal cases 
Cardiovascular beriberi is categorized into two main groups, according to its cause: alcoholic and non-alcoholic (dietary). Cardiovascular beriberi can also be divided into a fulminant form (Shoshin beriberi) and a chronic form. Shoshin beriberi is characterized by hypotension, tachycardia, and lactic acidosis and is mainly encountered in non-alcoholic patients in Asian countries, although it has also been seen in alcoholics in Western countries. Due to the complex clinical presentation and to the lack of diagnostic tests, thiamine deficiency is still being missed, especially among non-alcoholics patients. We present two fatal cases of non - alcohol associated cardiac beriberi. An acute myocardial infarction was observed in one case; extensive colliquative myocytolisis (grade 2) was described in the second case respectively. Morphologically, myocardial necrosis and colliquative myocytolysis are the histologic hallmarks of this acute, rare clinical entity. An increase in apoptotic myocytes was demonstrated probably sustaining the cardiogenic shock.
PMCID: PMC3034660  PMID: 21244717
16.  Distinct Signature of Altered Homeostasis in Aging Rod Photoreceptors: Implications for Retinal Diseases 
PLoS ONE  2010;5(11):e13885.
Advanced age contributes to clinical manifestations of many retinopathies and represents a major risk factor for age-related macular degeneration, a leading cause of visual impairment and blindness in the elderly. Rod photoreceptors are especially vulnerable to genetic defects and changes in microenvironment, and are among the first neurons to die in normal aging and in many retinal degenerative diseases. The molecular mechanisms underlying rod photoreceptor vulnerability and potential biomarkers of the aging process in this highly specialized cell type are unknown.
Methodology/Principal Findings
To discover aging-associated adaptations that may influence rod function, we have generated gene expression profiles of purified rod photoreceptors from mouse retina at young adult to early stages of aging (1.5, 5, and 12 month old mice). We identified 375 genes that showed differential expression in rods from 5 and 12 month old mouse retina compared to that of 1.5 month old retina. Quantitative RT-PCR experiments validated expression change for a majority of the 25 genes that were examined. Macroanalysis of differentially expressed genes using gene class testing and protein interaction networks revealed overrepresentation of cellular pathways that are potentially photoreceptor-specific (angiogenesis and lipid/retinoid metabolism), in addition to age-related pathways previously described in several tissue types (oxidative phosphorylation, stress and immune response).
Our study suggests a progressive shift in cellular homeostasis that may underlie aging-associated functional decline in rod photoreceptors and contribute to a more permissive state for pathological processes involved in retinal diseases.
PMCID: PMC2975639  PMID: 21079736
17.  A common allele in RPGRIP1L is a modifier of retinal degeneration in ciliopathies 
Nature genetics  2009;41(6):739-745.
Despite rapid advances in disease gene identification, the predictive power of the genotype remains limited, in part due to poorly understood effects of second-site modifiers. Here we demonstrate that a polymorphic coding variant of RPGRIP1L (retinitis pigmentosa GTPase regulator-interacting protein-1 like), a ciliary gene mutated in Meckel-Gruber (MKS) and Joubert (JBTS) syndromes, is associated with the development of retinal degeneration in patients with ciliopathies caused by mutations in other genes. As part of our resequencing efforts of the ciliary proteome, we identified several putative loss of function RPGRIP1L mutations, including one common variant, A229T. Multiple genetic lines of evidence showed this allele to be associated with photoreceptor loss in ciliopathies. Moreover, we show that RPGRIP1L interacts biochemically with RPGR, loss of which causes retinal degeneration, and that the 229T-encoded protein significantly compromises this interaction. Our data represent an example of modification of a discrete phenotype of syndromic disease and highlight the importance of a multifaceted approach for the discovery of modifier alleles of intermediate frequency and effect.
PMCID: PMC2783476  PMID: 19430481
18.  Inner Retinal Abnormalities in X-linked Retinitis Pigmentosa with RPGR Mutations 
Purpose. To investigate in vivo the retinal microstructure in X-linked retinitis pigmentosa (XLRP) caused by RPGR mutations as a prelude to treatment initiatives for this common form of RP.
Methods. Patients with RPGR-XLRP (n = 12; age range, 10–56 years) were studied by optical coherence tomography (OCT) in a wide region of central retina. Overall retinal thickness and outer nuclear layer (ONL) and inner retinal parameters across horizontal and vertical meridians were analyzed and compared.
Results. Retinal architecture of all patients with RPGR mutations was abnormal. At the fovea in younger patients, the ONL could be normal; but, at increasing eccentricities, there was a loss of photoreceptor laminar structure, even at the youngest ages studied. At later ages and advanced disease stages, the ONL was thin and reduced in extent. Inner retinal thickness, in contrast, was normal or hyperthick. Inner retinal thickening was detectable at all ages studied and was strongly associated with ONL loss.
Conclusions. Inner retinal laminar abnormalities in RPGR-XLRP are likely to reflect a neuronal–glial retinal remodeling response to photoreceptor loss and are detectable relatively early in the disease course. These results should be factored into emerging therapeutic strategies for this form of RP.
PMCID: PMC3178894  PMID: 17898302
19.  CFH haplotypes without the Y402H coding variant show strong association with susceptibility to age-related macular degeneration 
Nature genetics  2006;38(9):1049-1054.
In developed countries, age-related macular degeneration is a common cause of blindness in the elderly. A common polymorphism, encoding the sequence variation Y402H in complement factor H (CFH), has been strongly associated with disease susceptibility. Here, we examined 84 polymorphisms in and around CFH in 726 affected individuals (including 544 unrelated individuals) and 268 unrelated controls. In this sample, 20 of these polymorphisms showed stronger association with disease susceptibility than the Y402H variant. Further, no single polymorphism could account for the contribution of the CFH locus to disease susceptibility. Instead, multiple polymorphisms defined a set of four common haplotypes (of which two were associated with disease susceptibility and two seemed to be protective) and multiple rare haplotypes (associated with increased susceptibility in aggregate). Our results suggest that there are multiple disease susceptibility alleles in the region and that noncoding CFH variants play a role in disease susceptibility.
PMCID: PMC1941700  PMID: 16936733
20.  Intrabiliary Growth of Liver Metastases 
Intrabiliary growth by metastatic colorectal carcinoma (CRC) is an unusual finding that can clinically mimic cholangiocarcinoma. We evaluated prevalence of intrabiliary growth by retrospective review of 1596 diagnostic reports and by prospective evaluation of 223 hepatectomies. Positive cases were scored for extent of intrabiliary growth (major vs. minor duct involvement), architectural pattern (colonization of biliary epithelium and/or intrabiliary tumor plugs), and secondary sclerosing cholangitis in non-neoplastic parenchyma. By retrospective review, we identified intrabiliary growth in 41 (3.6%) of 1144 metastatic CRCs but only 3 (0.7%) of 452 noncolorectal tumors (P<0.001). Prospectively, we found intrabiliary growth in 18 (10.6%) of 170 metastatic CRCs and 1 (1.9%) of 53 other tumors (P=0.05). Among our final population of 43 CRCs with intrabiliary growth, 24 (56%) had major and 19 (44%) had minor duct involvement, 35 (81%) showed colonization of biliary epithelium, and 35 (81%) showed intrabiliary tumor plugs. Compared with minor duct involvement and 51 controls without intrabiliary growth, major duct involvement was more likely to produce obstructive liver chemistries (P=0.004), radiographic evidence of biliary disease (P<0.0001), and sclerosing cholangitis in non-neoplastic liver (P<0.0001). However, there was no impact on overall survival. Clinically, 5 (21%) cases of major duct involvement resulted in diagnostic uncertainty between metastatic CRC and cholangiocarcinoma. These findings underscore the frequency of intrabiliary growth by metastatic CRCs and its rarity with other metastases. Major duct involvement should be recognized because of its distinctive clinical features, which can overlap with cholangiocarcinoma.
PMCID: PMC3789528  PMID: 23797727
intrabiliary growth; metastasis; colorectal carcinoma; prevalence

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