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AIM: To investigate the expression of leukemia related protein 16 (LRP16), and the possible relationship between LRP16 expression and clinicopathological indices in 336 gastric carcinoma patients.

METHODS: Immunohistochemistry was used to detect LRP16 expression in 336 cases of paraffin-embedded gastric carcinoma tissues and 60 cases of distal normal mucosa. The relationships between LRP16 expression and patients’ age, tumor size, histological grade, clinical stage, metastatic status and prognosis were analysed.

RESULTS: The expression of LRP16 was 58.6% (197/336) in gastric carcinoma and 31.7% (19/60) in distal normal gastric mucosa. The expression of LRP16 in carcinoma was significantly higher than that in normal mucosa tissues (χ2 = 14.929, P = 0.001). LRP16 protein expression was found in 44.1% (63/143) carcinomas at stage I and II, and 69.4% (134/193) carcinomas at stage III and IV (χ2 = 21.804, P = 0.001), and in 56.9% (182/320) of cancers without metastasis but 93.8% (15/16) of those with metastasis (χ2 = 8.543, P = 0.003). The expression of LRP16 was correlated with tumor size, infiltrative depth, clinical stage, lymphatic invasion and distant metastasis (all P < 0.05). Follow-up data showed that there was a significant difference in median survival time between cancer patients with expression of LRP16 (27.0 mo) and those without (48.0 mo, Log rank =31.644, P = 0.001).

CONCLUSION: The expression of LRP16 may be associated with invasion, metastasis and prognosis of gastric cancer.

AIM: To analyse the expression of multidrug resistance (MDR) related proteins at different steps in colorectal carcinogenesis. METHODS: The presence of three MDR related proteins (Pgp, MRP1, and LRP/MVP) was studied by means of immunohistochemistry in normal, adenomatous, and malignant colorectal epithelium. Formaldehyde fixed, paraffin embedded tissue sections of 17 samples of colorectal tissue were used (normal mucosa, n = 4; adjacent mucosa, n = 5; adenoma, n = 5; carcinoma, n = 3). RESULTS: For all three proteins, expression was found in the surface epithelium and the upper parts of the crypts in normal colon. In the adenomas, staining was seen along the complete length of the crypts. In the carcinomas analysed, all epithelium showed positive staining. Mucosa adjacent to either carcinoma or adenoma showed staining patterns mostly resembling those of normal mucosa, but sometimes some extension of staining was seen along the crypt. CONCLUSIONS: These proteins already show increased expression in the adenoma stage. In the absence of adequate mucin production in adenomas, MDR related proteins could be an important factor in protecting the epithelium against further environmentally induced genetic damage. This could be one of the reasons why only about 5% of colorectal adenomas will actually progress to carcinomas.

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Background

Low-density lipoprotein receptor-related protein 1 (LRP1) is a multifunctional receptor involved in receptor-mediated endocytosis and cell signaling. The aim of this study was to elucidate the expression and mechanism of LRP1 in hepatocellular carcinoma (HCC).

Methods

LRP1 expression in 4 HCC cell lines and 40 HCC samples was detected. After interruption of LRP1 expression in a HCC cell line either with specific lentiviral-mediated shRNA LRP1 or in the presence of the LRP1-specific chaperone, receptor-associated protein (RAP), the role of LRP1 in the migration and invasion of HCC cells was assessed in vivo and in vitro, and the expression of matrix metalloproteinase (MMP) 9 in cells and the bioactivity of MMP9 in the supernatant were assayed. The expression and prognostic value of LRP1 were investigated in 327 HCC specimens.

Results

Low LRP1 expression was associated with poor HCC prognosis, with low expression independently related to shortened overall survival and increased tumor recurrence rate. Expression of LRP1 in non-recurrent HCC samples was significantly higher than that in early recurrent samples. LRP1 expression in HCC cell lines was inversely correlated with their metastatic potential. After inhibition of LRP1, low-metastatic SMCC-7721 cells showed enhanced migration and invasion and increased expression and bioactivity of MMP9. Correlation analysis showed a negative correlation between LRP1 and MMP9 expression in HCC patients. The prognostic value of LRP1 expression was validated in the independent data set.

Conclusions

LRP1 modulated the level of MMP9 and low level of LRP1 expression was associated with aggressiveness and invasiveness in HCCs. LRP1 offered a possible strategy for tumor molecular therapy.

Low-density lipoprotein receptor–related proteins 5 and 6 (Lrp5 and Lrp6) are co-receptors of Wnt ligands and play important roles in Wnt/β-catenin signal transduction. Mice homozygous for a germline deletion of Lrp6 die at birth with several associated defects, while Lrp5-deficient mice are viable. Here we conditionally deleted Lrp5 and/or Lrp6 in the mouse gut (gut−/−) by crossing mice carrying floxed alleles of Lrp5 and Lrp6 to a strain expressing Cre recombinase from the villin promoter (villin-Cre). The changes in morphology, differentiation and Wnt signal transduction were validated using immunohistochemistry and other staining. Consistent with observations in mice carrying a homozygous germline deletion in Lrp5, intestinal development in Lrp5gut−/− mice was normal. In addition, mice homozygous for villin-Cre–induced deletion of Lrp6 (Lrp6gut−/−) were viable with apparently normal intestinal differentiation and function. However, mice homozygous for villin-Cre inactivated alleles of both genes (Lrp5gut−/−;Lrp6gut−/−) died within one day of birth. Analysis of embryonic Lrp5gut−/−;Lrp6gut−/− intestinal epithelium showed a progressive loss of cells, an absence of proliferation, and a premature differentiation of crypt stem/precursor cells; no notable change in differentiation was observed in the embryos lacking either gene alone. Further immunohistochemical studies showed that expression of the Wnt/β-catenin target, cyclin D1, was specifically reduced in the intestinal epithelium of Lrp5gut−/−;Lrp6gut−/− embryos. Our data demonstrate that Lrp5 and Lrp6 play redundant roles in intestinal epithelium development, and that Lrp5/6 might regulate intestinal stem/precursor cell maintenance by regulating Wnt/β-catenin signaling.

The role of the cellular protein LRP6 in anthrax toxin entry is controversial. Previous studies showed that LRP6 was important for efficient intoxication of human M2182 prostate carcinoma cells but other studies performed with cells from gene-knockout mice demonstrated no role for either LRP6 or the related LRP5 protein in anthrax toxin entry. One possible explanation for this discrepancy is that LRP6 may be important for anthrax toxin entry into human, but not mouse, cells. To test this idea we have investigated the effect of knocking down LRP6 or LRP5 expression with siRNAs in human HeLa cells. We show here that efficient knockdown of either LRP6, LRP5, or both proteins has no influence on the kinetics of anthrax lethal toxin entry or MEK1 substrate cleavage in these cells. These data argue against a human-specific role for LRP6 in anthrax toxin entry and suggest instead that involvement of this protein may be restricted to certain cell types independently of their species of origin.

Purpose

Although stromal-cell-derived factor (SDF)-1α is suggested to be involved in tumorigenicity and tumor angiogenesis, the clinicopathological significance of its expression in colorectal cancers is not fully understood. We examined SDF-1α expression in colorectal cancers and investigated its relationship to clinicopathological features such as tumor staging, lymph-node metastasis, vascular invasion (VI), lymphatic invasion (LI) and neural invasion (NI).

Methods

Specimens of 83 primary colorectal cancers were examined immunohistochemically, and the relationships between clinicopathological features and SDF-1α expression were analyzed. To compare the expressions between the normal colon tissue and colorectal cancer tissues, we performed Western blot analyses.

Results

According to the Western blot analyses, SDF-1α was more highly expressed in colorectal carcinoma tissues than in normal colonic mucosa (20/21). According to the immunohistochemical stain, SDF-1α was associated with nodal status, distant metastasis, tumor staging, VI and LI. SDF-1α expression had a significant prognostic value for overall survival. Kaplan-Meier plots of survival in patients with high SDF-1α showed that high SDF-1α expression was associated with a shorter overall survival. However, no association was found between SDF-1α expression and other pathologic or clinical variables, including age, gender, degree of differentiation, and presence of perineural invasion.

Conclusion

The expression of SDF-1α might be associated with tumor progression in colorectal cancer. Inhibition of SDF-1α could be a therapeutic option in colorectal cancer patients.

AIM: To explore the relation between B-cell-specific Moloney murine leukemia virus insertion site 1 (Bmi-1) expression and the clinicopathological features of gastric carcinoma (GC).

METHODS: Immunohistochemistry was used to detect the expression of Bmi-1 and ki-67. Double-labeling staining was used to display the distribution of Bcl-2+/ki-67- cells in 162 cases of GC and its matched normal mucosa and precancerous lesion.

RESULTS: The positive rate of Bmi-1 expression in GC (52.5%) was significantly higher than that in normal gastric mucosa (21.6%, χ2 = 33.088, P < 0.05). The Bmi-1 expression in GC was closely related with the Lauren’s and Borrmann’s classification and clinical stage (χ2 = 4.400, 6.122 and 11.190, respectively, P < 0.05). The expression of ki-67 was related to the Borrmann’s classification (χ2 = 13.380, P < 0.05). Bcl-2 expression was correlated with the Lauren’s classification (χ2 = 4.725, P < 0.05), and the Bmi-1 expression both in GC (rk = 0.157, P < 0.05) and in intestinal metaplasia (rk = 0.270, P < 0.05).

CONCLUSION: Abnormal Bmi-1 expression in GC may be involved in cell proliferation, apoptosis and cancerization. This marker can objectively indicate the clinicopathological characteristics of GC.

AIMS--Immunostaining of chromogranin identifies gastrointestinal mucosal endocrine cells. The detailed distribution and significance of chromogranin positive cells in colorectal carcinomas and in transitional mucosa remain unclear. The aim of this study was to clarify these aspects. METHODS--The distribution of chromogranin positive cells was studied by immunohistochemical methods in normal epithelium remote from carcinoma, in transitional mucosa, and in carcinomas of the colorectum. In selected cases northern or western blot analyses were performed. RESULTS--Chromogranin positive cells were seen in the lower third of the normal crypts and less frequently in transitional mucosa. Thirty five per cent (n = 38) of colorectal carcinomas showed immunohistochemically positive carcinoma cells in the tumour tissue. Northern and western blot analyses showed similar results. There was no difference in clinicopathological factors, including prognosis, between chromogranin positive cases of colorectal carcinoma (n = 38) and chromogranin negative cases (n = 70). CONCLUSIONS--Neuroendocrine cell differentiation is controlled in transitional mucosa and the presence of chromogranin positive cells in carcinoma tissue does not influence the patient's prognosis.

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Reactive oxygen metabolites are implicated in the initiation and promotion of cancer. In addition, oxidant scavengers, such as manganese--(Mn-SOD) and copper/zinc--superoxide dismutase (Cu/Zn-SOD), are thought to contribute to colorectal cancer treatment response. In the present study, the prognostic significance of the Mn- and Cu/Zn-SOD antigen content of normal mucosa and carcinomas of 163 patients with colorectal cancer was evaluated in comparison with major clinicopathological parameters, with respect to the 5-year overall survival. The Mn-SOD content of carcinomas was found to be significantly higher than that of normal mucosa, whereas there was no difference in the Cu/Zn-SOD content between the normal mucosa and carcinomas. No association was demonstrable between the Mn-SOD and Cu/Zn-SOD content of the tissues and the assessed clinicopathological parameters (gender, age, localization, differentiation grade, diameter and Dukes' stage), with the exception of the Cu/Zn-SOD and the differentiation grade of the carcinomas. Univariate analysis showed that a high Mn-SOD content of carcinomas was associated with a poor 5-year overall survival of the patients with colorectal cancer. Multivariate analysis including all clinicopathological parameters revealed that this Mn-SOD parameter was prognostically independent. The Mn- and Cu/Zn-SOD content of normal mucosa and the Cu/Zn-SOD content of carcinomas were not associated with the overall survival of the patients. In conclusion, this study demonstrates that for patients with colorectal cancer the Mn-SOD content of colorectal carcinomas has a significant prognostic value that is independent from major clinicopathological parameters, including Dukes' stage.

The immunolocalization of the low density lipoprotein receptor-related protein 1 (LRP1) and its ligand alpha 2-Macroglobulin (α2M) was examined in tissues from human donor eyes of normal, diabetic and sickle cell disease subjects. Streptavidin alkaline phosphatase immunohistochemistry was performed with a mouse anti-human LRP1 and rabbit anti-human α2M antibodies. Retinal and choroidal blood vessels were labeled with mouse anti-human CD34 antibody in adjacent tissue sections. Mean scores for immunostaining from the pathological and control eyes were statistically compared.

LRP1 immunoreactivity was very weak to negative in the neural retina of normal subjects except in scattered astrocytes. LRP1 expression in diabetic eyes was detected in the inner limiting membrane (ILM), astrocytes, inner photoreceptor matrix, choriocapillaris and choroidal stroma. The ligand α2M, however, was limited mainly to blood vessel walls, some areas of the inner nuclear layer (INL), photoreceptors, RPE-Bruch’s membrane–choriocapillaris complex, intercapillary septa, and choroidal stroma. In sickle cell eyes, avascular and vascular retina as well as choroidal neovascularization (CNV) were analyzed. In avascular areas, LRP1 immunoreactivity was in innermost retina (presumably ILM, astrocytes, and Muller cells) and INL as well as RPE–Bruch’s membrane–choriocapillaris complex and choroidal stroma. α2M was very weak in avascular peripheral retina compared to vascularized areas and limited to stroma in choroid. In contrast, in areas with CNV, LRP1 immunoreactivity was significantly decreased in overlying retina and in RPE–Bruch’s membrane and choroidal stroma compared to the controls, while α2M was elevated in RPE–Bruch’s membrane near CNV compared to normal areas in sickle cell choroid. The mean scores revealed that LRP1 and α2M in neural retina were significantly elevated in astrocytes and ILM in diabetic eyes (p ≤ 0.05), whereas in sickle cell eyes scores were elevated in ILM and INL (p ≤ 0.05). In addition, α2M immunoreactivity was in photoreceptors in both ischemic retinopathies. In choroid, the patterns of LRP1 and α2M expression were different and not coincident.

This is the first demonstration of the presence of LRP1 and α2M in human proliferative retinopathies. Elevated LRP1 expression in sickle cell neural retina and diabetic inner retina and choroid suggests that LRP1 plays an important role in ischemic neovascular diseases.

Background

Breast cancer is a common malignant disease, which may be caused by a number of genes deregulated by genomic or epigenomic events. Deregulated WNT/β-catenin signaling with accumulation of β-catenin is common in breast tumors, but mutations in WNT signaling pathway components have been rare. An aberrantly spliced internally truncated LRP5 receptor (LRP5Δ666–809, LRP5Δ) was shown recently to be resistant to DKK1 inhibition, and was required for β-catenin accumulation in hyperparathyroid tumors and parathyroid tumor growth.

Methodology/Principal Findings

Here we show, by reverse transcription PCR and Western blot analysis, that LRP5Δ is frequently expressed in breast tumors of different cancer stage (58–100%), including carcinoma in situ and metastatic carcinoma. LRP5Δ was required in MCF7 breast cancer cells for the non-phosphorylated active β-catenin level, transcription activity of β-catenin, cell growth in vitro, and breast tumor growth in a xenograft SCID mouse model. WNT3 ligand, but not WNT1 and WNT3A augmented the endogenous β-catenin activity of MCF7 cells in a DKK1-insensitive manner. Furthermore, an anti-LRP5 antibody attenuated β-catenin activity, inhibited cell growth, and induced apoptosis in LRP5Δ-positive MCF7 and T-47D breast cancer cells, but not in control cells.

Conclusions/Significance

Our results suggest that the LRP5Δ receptor is strongly implicated in mammary gland tumorigenesis and that its aberrant expression present an early event during disease progression. LRP5 antibody therapy may have a significant role in the treatment of breast cancer.

LRP1b and the closely related LRP1 are large members of the low-density lipoprotein receptor family. At the protein level LRP1b is 55% identical to LRP1, a multifunctional and developmentally essential receptor with roles in cargo transport and cellular signaling. Somatic LRP1b mutations frequently occur in non-small cell lung cancer and urothelial cancers, suggesting a role in the modulation of cellular growth. In contrast to LRP1, LRP1b-deficient mice develop normally, most likely due to its restricted expression pattern and functional compensation by LRP1 or other receptors. LRP1b is expressed predominantly in the brain, and a differentially spliced form is present in the adrenal gland and in the testis. Despite the presence of a potential furin cleavage site and in contrast to LRP1, immunoblotting for LRP1b reveals the presence of a single 600-kDa polypeptide species. Using a yeast two-hybrid approach, we have identified two intracellular proteins, the postsynaptic density protein 95 and the aryl hydrocarbon receptor-interacting protein, that bind to the intracellular domain of LRP1b. In addition, we have found several potential ligands that bind to the extracellular domain. Analysis of LRP1b knockout mice may provide further insights into the role of LRP1b as a tumor suppressor and into the mechanisms of cancer development.

Despite the advances in pre-, peri- and post-operative medical care of colorectal carcinoma patients, the prognosis has improved only marginally over recent decades. Thus, additional prognostic indicators would be of great clinical value to select patients for adjuvant therapy. In previous studies we found that colorectal carcinomas have a marked increase of the urokinase-type of plasminogen activator (u-PA), and the inhibitors PAI-1 and PAI-2, whereas the tissue-type plasminogen activator (t-PA) is found to be decreased in comparison with adjacent normal mucosa. In the present study we evaluated the prognostic value of several plasminogen activation parameters, determined in both normal and carcinomatous tissue from colorectal resection specimens, for overall survival of 136 Dukes' stage B and C colorectal cancer patients, in relation to major clinicopathological parameters. Uni- and multivariate analyses indicated that a high PAI-2 antigen level in carcinoma, a low t-PA activity and antigen level and a high u-PA/t-PA antigen ratio in adjacent normal mucosa are significantly associated with a poor overall survival. A high ratio of u-PA antigen in the carcinomas and t-PA antigen in normal mucosa, i.e. u-PA(C)/t-PA(N), was found to be predictive of a poor overall survival as well. All these parameters were found to be prognostically independent of the clinicopathological parameters. Multivariate analysis of combinations of these prognostically significant plasminogen activation parameters revealed that they are important independent prognostic indicators and have in fact a better prognostic value than their separate components. Based on these combined parameters, subgroups of patients with Dukes' stage B and C colorectal cancer could be identified as having either a high or a low risk regarding overall survival. In conclusion, these findings emphasize the relevance of the intestinal plasminogen activation system for survival prognosis of patients with colorectal cancer and, in the future, might constitute a patient selection criterion for adjuvant therapy.

Background

Leptin is an adipocyte‐derived neurohormone, high levels of which are found in obese individuals. Leptin controls energy expenditure, acting in the brain, and regulates different processes in peripheral organs. Recent studies have suggested that leptin may be involved in cancer development and progression.

Aims

To analyse leptin expression in human colorectal cancer as well as in colorectal mucosa and colorectal adenomas.

Methods

Leptin expression was assessed by immunohistochemistry in 166 colorectal cancers, 101 samples of colorectal mucosa and 41 adenomas. Leptin concentration in colorectal cancer was correlated with selected clinicopathological features.

Results

Immunoreactivity for leptin was observed in 51.2% (85/166) of primary colorectal cancers. In adenomas leptin expression was observed in 14.6% (6/41) of studied cases. In normal mucosa, leptin was present at low levels, except in tumour bordering areas where its concentration appeared to reflect levels in the adjacent cancer tissue. Leptin expression in colorectal cancer significantly correlated with tumour G2 grade (p = 0.002) as well as with histological type (adenocarcinoma) of tumours (p = 0.044).

Conclusions

Results indicate that leptin is overexpressed in human colorectal cancer, which suggests that the hormone might contribute to colorectal cancer development and progression.

Purpose

Glucose uptake and glycolytic metabolism are enhanced in cancer cells, and increased expression of glucose transporter 1 (GLUT1) has also been reported. The aim of this study was to investigate GLUT1 expression in human breast tissues and invasive ductal carcinomas.

Methods

We used tissue microarrays consisting of normal breast tissue, ductal hyperplasia, ductal carcinoma in situ, invasive ductal carcinoma, and lymph node metastases. We examined GLUT1 expression in the microarrays by immunohistochemistry, reviewed the medical records and performed a clinicopathological analysis.

Results

Membranous GLUT1 expression was observed in normal and tumor cells. GLUT1 expression was higher in ductal carcinoma in situ, invasive ductal carcinoma, and lymph node metastasis than in normal tissue and ductal hyperplasia (p=0.002). Of 276 invasive ductal carcinomas, 106 (38.4%) showed GLUT1 expression. GLUT1 expression was correlated with higher histologic grade (p<0.001), larger tumor size (p=0.025), absence of estrogen receptor (p<0.001), absence of progesterone receptor (p<0.001), and triple-negative phenotype (p<0.001). In univariate survival analysis, patients with GLUT1 expression had poorer overall survival and disease-free survival (p=0.017 and p=0.021, respectively, log-rank test). In multivariate survival analysis with the Cox proportional hazards model, GLUT1 expression was an independent prognostic factor of poorer overall survival and disease-free survival (p=0.017 and p=0.019, respectively).

Conclusion

GLUT1 expression seems to play an important role in malignant transformation, and the glycolytic phenotype in invasive ductal carcinoma may indicate aggressive biological behavior and a worse prognosis.

Mitotic centromere-associated kinesin (MCAK) is a microtubule depolymerase that is essential for proper kinetochore–microtubule attachment during spindle formation. Overexpression of MCAK has been correlated with aggressive forms of carcinoma, resulting in poor prognosis of colorectal cancer. The purpose of this study was to quantify MCAK expression in malignant and benign colorectal tissues and to determine if MCAK expression levels correlate with clinicopathologic factors and prognosis in colorectal cancer patients. Paired colorectal tissue samples from tumours and the corresponding normal tissues were obtained from 120 patients with colorectal cancer who underwent surgical resection. The real-time reverse transcriptase-PCR and immunohistochemistry were used to analyse mRNA and protein expression status with respect to various clinicopathological factors. MCAK expression was higher in colorectal cancer tissue (P<0.01) than in corresponding normal tissue, and this elevated expression level was markedly associated with factors such as lymph node metastasis (P=0.0023), venous invasion (P=0.019), peritoneal dissemination (P=0.021) and Dukes' classification (P=0.0023). Patients with high MCAK mRNA expression also showed a far poorer survival rate than those with low MCAK mRNA expression (P<0.01). Elevated MCAK expression was an independent predictor of overall survival and lymph node metastasis. These data suggest that MCAK expression may serve as a good marker of prognosis and lymph node metastasis in colorectal cancer.

Purpose

There is growing evidence implicating that neutrophil gelatinase–associated lipocalin (NGAL) plays a role in the development and progression of cancers. However, the effect of NGAL in colorectal carcinoma (CRC) has not been clearly elucidated. In this study, we investigated the role of NGAL in the tumorigenesis and progression of CRC and evaluated the clinical value of NGAL expression.

Experimental Design

We examined NGAL expression in 526 colorectal tissue samples, including 53 sets of matched specimens (histologically normal mucosa, adenomas, and carcinomas) using immunohistochemical analysis. In CRCs, correlations between NGAL expression and clinicopathologic parameters were analyzed, and survival analysis was conducted. The role of NGAL was further tested using mouse xenograft models.

Results

NGAL expression was elevated during the colorectal adenoma–carcinoma sequence both among the 526 cases (rs = 0.66, P < 0.001) and in the 53 sets of matched specimens (rs = 0.60, P < 0.001). In CRCs, NGAL expression was associated with cancer stage (P = 0.041) and tumor recurrence in stage II patients (P = 0.037). Survival analysis revealed that NGAL expression was an independent prognostic factor for overall survival (HR = 1.84, P = 0.004) and for disease-free survival of stage II patients (HR = 5.88, P = 0.021). In mouse models, the xenografts in cecum and spleen were heavier and more numerous in the group injected with NGAL-overexpressing CRC cells (P < 0.05).

Conclusions

NGAL overexpression may promote the tumorigenesis and progression of CRC. Detecting NGAL expression in tumor tissues may be useful for evaluating prognosis of patients with CRC.

Purpose

LRP1 is a broadly-expressed receptor that binds multiple extracellular ligands and participates in protein clearance. LRP1 is expressed numerous cancers, but its role in lung cancer has not been characterized. Here, we investigate the relationship between LRP1 and lung cancer.

Experimental Design

LRP1 mRNA levels were determined in lung tumors from several large, multicenter studies. LRP1 protein localization was determined by immunohistochemical analysis of lung tumor microarrays. Normal fibroblasts, fibroblasts treated with the LRP1 inhibitor RAP, and LRP1 null fibroblasts were co-cultured with three independent lung cancer cell lines to investigate the role of LRP1 on tumor cell proliferation.

Results

LRP1 mRNA levels are significantly decreased in lung tumors relative to non-tumorous lung tissue. Lower expression of LRP1 in lung adenocarcinomas correlates with less favorable clinical outcome in a cohort of 439 patients. Immunohistochemical analysis demonstrates that LRP1 is primarily expressed in stromal cells in 94/111 lung cancers, with very little protein found in cancer cells. A growth suppressive function of mouse embryonic fibroblast cells (MEF) was observed in three lung cancer cell lines tested (H460, H2347, and HCC4006 cells); growth suppression was blocked by the LRP1 inhibitor, RAP. LRP1 deletion in fibroblasts reduced the ability of MEF cells to suppress tumor cell mitosis. In a validation set of adenocarcinomas, we confirmed a significant positive correlation between both LRP1 mRNA and protein levels and favorable clinical outcomes.

Conclusions

LRP1 expression is associated with improved lung cancer outcomes. Mechanistically, stromal LRP1 may non-cell autonomously suppress lung tumor cell proliferation.

Background/aim: Retinoblastoma is the commonest primary intraocular tumour in children. Chemotherapy now plays a big part in the treatment of these tumours. There is not much information about the role of the multidrug resistance proteins (MDR)—P-glycoprotein (P-gp) and vault protein lung resistance protein (LRP)—in retinoblastoma. The authors investigated the expression of P-gp and LRP in retinoblastoma and correlated them clinicopathologically.

Methods: Among 60 retinoblastomas, 40 tumours were not subjected to preoperative or postoperative chemotherapy and 20 tumours were subjected to postoperative chemotherapy. In this cohort 27 tumours had no invasion and 33 tumours had invasion of choroid, optic nerve, and orbit. P-gp and LRP expression were studied by immunohistochemistry. Immunoanalysis was done semiquantitatively.

Results: Among the 60 tumours P-gp was expressed in 23 (38%) tumours and LRP was expressed in 35 (58%). P-gp was expressed in 11/27 (40%) tumours with no invasion and in 12/33 (36%) tumours with invasion. LRP was expressed in 15/27 (55%) tumours with no invasion and in 20/33 (60%) tumours with invasion. Both P-gp and LRP were negative in three tumours with invasion, which had later developed bone marrow metastasis. There was no correlation between P-gp and LRP expression with invasion, differentiation and laterality of the tumours and response to treatment.

Conclusion: Retinoblastoma expresses P-gp and LRP intrinsically before chemotherapy and none of these proteins predicted the response to chemotherapy. Thus, further studies are needed to understand the significance of the expression of the P-gp and LRP proteins in retinoblastoma.

TNM post-surgical staging is considered to be one of the most powerful prognosticators for colorectal carcinoma. Although patient survival mostly decreases concomitantly to stage increase, in a percentage of cases TNM stage appears only to express the anatomic extent of the neoplasia with no correlation with clinical outcome. Thus, the identification of additional prognostic markers for colorectal cancer is required. Neutrophil gelatinase-associated lipocalin (NGAL) is a 25-kDa protein that appears to play an important role in colorectal cancer progression. In order to evaluate whether NGAL expression may be considered as a predictor of colorectal cancer progression, we analyzed its correlation with clinicopathological characteristics, as well as with patient progression-free survival in a series of surgically resected colorectal carcinomas. A variable NGAL immunoexpression was found in 24 out of the 64 analyzed cases. When only the positive cases were considered, a significant association was found between a high NGAL expression and the presence of distant metastases or high tumor stage. In addition, the presence of NGAL was a significant negative prognostic marker correlated with a shorter progression-free survival in stage I colorectal carcinoma, but not in the remaining TNM stages. If our findings are confirmed in more extensive analyses on stage I colorectal carcinoma, NGAL assessment may be used in order to select those patients with a higher progression risk and to submit them to adjuvant therapies useful to prevent adverse outcome.

Background

There are no established reports about the expression of the Piwil gene, a subfamily of the Piwi gene involved in RNA silencing and self-renewal, in colorectal carcinomas. It is known that the degree of PIWIL2 expression is higher in colorectal carcinomas. But its clinicopathologic significance remains undetermined. This study reassessed the relationship between PIWIL2 expression and the clinicopathologic parameters in colorectal carcinomas.

Methods

An immunohistochemistry of PIWIL2 expression was done in 60 cases of colorectal carcinoma. This was followed by an analysis of the correlation between PIWIL2 expression and clinicopathologic features and a survival analysis.

Results

There were 44 cases (73.3%) where the degree of PIWIL2 expression was relatively higher. The high degree of PIWIL2 expression was significantly correlated with the lower degree of differentiation (p=0.039), deep invasion (p=0.019) and perineural invasion (p=0.027). The overall survival was longer in patients with the lower degree of PIWIL2 expression than in those with the higher degree of PIWIL2 expression.

Conclusions

Our results showed that the degree of PIWIL2 expression was relatively higher in colorectal carcinomas and it was significantly correlated with variable clinicopathologic indicators for a poor prognosis. This indicates that PIWIL2-positive cells contribute to the progression of colorectal cancer.

Telomere shortening and telomerase activation occur frequently in cases of colorectal carcinoma. In this study, we correlated the clinicopathological parameters with the telomere length in colorectal carcinomas, colonic polyps, and normal colonic tissues. We also investigated whether the telomere length changes reflect the biologic behavior of tumors and different modes of tumor development. Telomere length was determined by terminal restriction fragment Southern blot analysis in 20 invasive colorectal carcinomas and normal mucosa from the same patients. We also examined 20 colonic polyps and associated normal mucosa. Telomere shortening was detected in 16/20 (80%), and telomere elongation in 2/20 (10%) cases of colorectal carcinoma, and no changes in 2 subjects. In the colonic polyp patients, shortening was detected in 4/20 (20%), elongation in 6/20 (30%), and no change in 10/20 (50%). The frequency of telomere shortening was significantly different between colorectal carcinoma and polyp groups. Decreased telomere length was noted in 92.9% (13/14) of Dukes' C and 50% (3/6) of Dukes' B. The difference between these two sub-groups was statistically significant. This study suggests that the telomere length in colorectal carcinomas is decreased upon the development of malignancy. A significant difference in telomere length between polyps and invasive colorectal carcinomas may reflect a different biologic behavior of colorectal carcinomas.

Introduction:

The objective of this study was to identify and compare the costs of laparoscopic radical prostatectomy (LRP) and radical retropubic prostatectomy (RRP) at our centre.

Methods:

We conducted a retrospective chart review of our first 70 consecutive LRP cases and 70 consecutive RRP cases at St. Joseph’s Healthcare in Hamilton, Ontario, Canada. We performed cost analysis, including operating room costs, disposable instruments, blood transfusions, analgesic requirements and length of hospital stay. Overall expenses were then analyzed and compared.

Results:

Preoperative patient demographics and disease stages were comparable between the LRP and RRP groups. On a per procedure basis, large discrepancies were found in mean disposable instrument costs (LRP = $659.18 vs. RRP = $236.59), operating room costs (LRP = $4278.00 vs. RRP = $3139.00), mean cost of blood transfusions (LRP = $21.00 vs. RRP = $394.34), mean analgesia requirements (LRP = $12.94 vs. RRP = $41.06) and mean hospital stay bed costs (LRP = $3690.00 vs. RRP = $5027.14). Overall, costs for all patients in the LRP and RRP groups, respectively, were $606 307.29 and $618 721.57 with a cost saving of $12 414.28 in favour of the LRP arm.

Conclusion:

At our institution, we found that LRP costs are slightly less than those for RRP. Higher operative time and disposable instrument expenses are offset by the shorter hospital stays, fewer blood transfusions and less analgesic requirements for the LRP group. Further financial advantages for LRP will likely be achieved with additional reduction of operating room time and by minimizing disposables.

Background/Aims

Krüppel-like factor 4 (KLF4) is an epithelial-specific transcription factor primarily expressed in the gastrointestinal tract that mediates growth arrest in the colonic epithelium. We tried to find whether KLF4 expression is associated with the progression and differentiation of colorectal cancer.

Methods

We detected KLF4 expression in 109 colorectal specimens (40 normal appearing mucosa, 7 adenomas, and 62 carcinomas) by immunohistochemistry using a tissue microarray. Western blot and RT-PCR analyses were also performed.

Results

The upregulation of KLF4 expression in carcinoma tissue was statistically significant (p<0.05) when compared to normal appearing mucosa. The negative and weak positive staining rates in normal appearing mucosa, adenoma, and carcinoma were 42.5%, 71.4%, and 82.3%, respectively, indicating a decreased degree of KLF4 expression over the course of progressive transformation of normal cells into malignant derivatives. KLF4 protein levels showed no correlation with sex, age, or metastatic state (p>0.05), while KLF4 protein expression correlated with the diagnostic stage (p<0.05). Furthermore, strong KLF4 staining was detected in 22.9% (11/48) and 0% (0/14) of well/moderately and poorly differentiated colorectal cancers, respectively. Our results clearly indicate that KLF4 protein expression significantly correlates with the degree of differentiation in colorectal cancers (p<0.05). KLF4 expression in RKO cells is also upregulated by butyrate, an inducer of differentiation.

Conclusions

Downregulation of KLF4 expression may lead to more poorly differentiated tumors.

Background

Activation of MEK5 in many cancers is associated with carcinogenesis through aberrant cell proliferation. In this study, we determined the level of phosphorylated MEK5 (pMEK5) expression in human colorectal cancer (CRC) tissues and correlated it with clinicopathologic data.

Methods

pMEK5 expression was examined by immunohistochemistry in a tissue microarray (TMA) containing 335 clinicopathologic characterized CRC cases and 80 cases of nontumor colorectal tissues. pMEK5 expression of 19 cases of primary CRC lesions and paired with normal mucosa was examined by Western blotting. The relationship between pMEK5 expression in CRC and clinicopathologic parameters, and the association of pMEK5 expression with CRC survival were analyzed respectively.

Results

pMEK5 expression was significantly higher in CRC tissues (185 out of 335, 55.2%) than in normal tissues (6 out of 80, 7.5%; P < 0.001). Western blotting demonstrated that pMEK5 expression was upregulated in 12 of 19 CRC tissues (62.1%) compared to the corresponding adjacent nontumor colorectal tissues. Overexpression of pMEK5 in CRC tissues was significantly correlated to the depth of invasion (P = 0.001), lymph node metastasis (P < 0.001), distant metastasis (P < 0.001) and high preoperative CEA level (P < 0.001). Consistently, the pMEK5 level in CRC tissues was increased following stage progression of the disease (P < 0.001). Analysis of the survival curves showed a significantly worse 5-year disease-free (P = 0.002) and 5-year overall survival rate (P < 0.001) for patients whose tumors overexpressed pMEK5. However, in multivariate analysis, pMEK5 was not an independent prognostic factor for CRC (DFS: P = 0.139; OS: P = 0.071).

Conclusions

pMEK5 expression is correlated with the staging of CRC and its expression might be helpful to the TNM staging system of CRC.