Nan Haw Chow

Expression of vascular endothelial growth factor in normal liver and hepatocellular carcinoma: An immunohistochemical study

Angiogenesis is of vital importance during the development and progression of solid tumors. To examine the role of vascular endothelial growth factor (VEGF) in hepatocarcinogenesis, we evaluated the expression of peptide in normal human liver (n = 6) and in 36 cases of hepatocellular carcinoma (HCC). Immunoreactivity for VEGF was present in the extracellular matrix of the portal tracts in the normal and nontumor part of liver, but not in hepatocytes and bile duct epithelium. For HCC, variable amounts of VEGF were expressed in 13 cases (36.1%) of tumor cells. Using a logistic regression model, expression of VEGF was significantly associated with a higher proliferative index (P = .01) and sonographic portal vein thrombosis (P = .05). However, VEGF expression did not correlate with a biochemical liver profile, alpha-fetoprotein levels, histological grading, gender, or clinical stage of cirrhosis (P > 0.1, respectively). Log-rank test showed that evaluation of VEGF did not provide more prognostic information (P > .5) than that from tumor volume and portal vein thrombosis (P < .01, respectively). In addition, VEGF was always present in the fibrovascular stroma or pericellular matrix of HCC, although no strong relationship was observed with the expression of VEGF in tumor cells (P > .5). Our data suggested that expression of VEGF may characterize a progression toward higher proliferation in hepatocarcinogenesis in vivo. The relevance of VEGF existing in the extracellular matrix of the normal liver and HCC remains to be clarified.

Prognostic Significance of Co-expression of RON and MET Receptors in Node-Negative Breast Cancer Patients

Purpose: RON and MET belong to a subfamily of tyrosine kinase receptors. They both can induce invasive growth, including migration, cell dissociation, and matrix invasion. Cross-linking experiments show that RON and MET form a noncovalent complex on the cell surface and cooperate in intracellular signaling. We wanted to examine the clinical significance of RON and MET expression patterns in node-negative breast cancer. Experimental Design: We studied the protein expressions of RON and MET in five breast cancer cell lines and a homogeneous cohort of 103 T1-2N0M0 breast carcinoma patients, including 52 patients with distant metastases and 51 patients with no evidence of disease after at least a 10-year follow-up. Results: Both HCC1937 and MDA-MB-231 cancer cell lines co-overexpressed RON and MET. The MCF-7 cell line did not express RON or MET. In multiple logistic regression analysis, RON expression (odds ratio, 2.6; P = 0.05) and MET expression (odds ratio, 4.7; P = 0.009) were independent predictors of distant relapse. RON+/MET+ and RON−/MET+ tumors resulted in a large risk increase for 10-year disease-free survival after adjusting for tumor size, histologic grade, estrogen receptor, bcl-2, HER-2/neu, and p53 status by multivariate Cox analysis (risk ratio, 5.3; P = 0.001 and risk ratio, 3.76; P = 0.005). The 10-year disease-free survival was 79.3% in patients with RON−/MET− tumors, was only 11.8% in patients with RON+/MET+ tumors, and was 43.9% and 55.6% in patients with RON−/MET+ and RON+/MET− tumors. Conclusions: Co-expression of RON and MET seems to signify an aggressive phenotype in node-negative breast cancer patients.

Papillary urothelial hyperplasia is a clonal precursor to papillary transitional cell bladder cancer.

Papilloma and papillary hyperplasia (PH) have been proposed to be the putative precursor lesions of papillary transitional‐cell carcinoma of the urinary bladder. We examined 15 PH lesions and 4 papillomas for loss of heterozygosity (LOH) at 17 microsatellite markers on 9 chromosomal arms. Eight of 15 (53%) PHs were clonal, demonstrating LOH of at least 1 microsatellite marker. In contrast, none of the papillomas showed any genetic changes among the markers tested. In PH, chromosomal arm 9q was the most frequently lost (4/15), followed by 9p and 18q (n = 2) and, less frequently, 8p, 10q, 11p and 17p (n = 1). Furthermore, 2 hyperplastic lesions demonstrated LOH at 9q only, confirming the notion that allelic loss on chromosomal arm 9q is among the earliest events in bladder‐cancer progression. In 1 patient, identical LOH patterns were observed between PH and a recurrent transitional‐cell carcinoma. Our molecular data demonstrate that at least a proportion of PHs represent pre‐cancerous lesions of the bladder that subsequently progress to papillary bladder cancer. Moreover, chromosomal arm 9q may harbor a tumor‐suppressor gene(s) inactivated in the earliest stages of human bladder tumorigenesis. Int. J. Cancer 89:514–518, 2000.

Overexpression of c-met as a Prognostic Indicator for Transitional Cell Carcinoma of the Urinary Bladder: A Comparison With p53 Nuclear Accumulation

PURPOSE The c-met proto-oncogene encodes a receptor tyrosine kinase (Met) and has been shown to play a role in oncogenesis. Given that high titers of hepatocyte growth factor, the specific ligand for Met, are excreted in the urine and tend to reflect disease activity of bladder cancer, we performed this study to examine the clinical significance of Met in human bladder cancer. MATERIALS AND METHODS We studied the mRNA expression and genomic alteration of c-met in five bladder cancer cell lines. Significance of Met overexpression was then compared with p53 nuclear accumulation (TP53) in primary bladder cancer (n = 142 patients). RESULTS Expression of c-met mRNA tended to positively correlate with differentiation of cancer cell lines in the absence of point mutation. High expression of Met was found in seven cases (4.9%), low expression in 32 cases (22.5%), and negative expression in 103 cases (72.5%). Expression of Met was positively associated with histologic grade, stage classification, tumor size, and nodular tumor growth (P <.05, respectively); however, it was not related to TP53 status. Factors that predicted disease progression were tumor stage, Met status, and TP53 accumulation (P <.05, respectively). Indicators for poor long-term survival were invasive cancer, multiple tumors, and Met overexpression (P =.0006,.01, and.04, respectively). CONCLUSION The c-met proto-oncogene plays a more important role in the progression of bladder carcinogenesis than p53. Evaluation of Met expression could identify a subset of bladder cancer patients who may require a more intensive treatment strategy.

Expression patterns of erbB receptor family in normal urothelium and transitional cell carcinoma. An immunohistochemical study.

Abstract The class I tyrosine kinase growth-factor receptors include epidermal growth factor receptor (EGFR), ErbB2 (c-erbB-2, HER-2/neu), ErbB3 and ErbB4. To elucidate their role in the regulation of homeostasis and carcinogenesis, we examined the expression of the receptors in normal urothelium and in urothelial carcinoma by immunohistochemistry. EGFR was expressed in the basal cells of normal urothelium, while ErbB2, ErbB3 and ErbB4 were present mainly in the superficial layer. A distinct reciprocal distribution was observed between the EGFR and the remaining members of the subclass (P = 0.0001). Both BCL-2 protein and Ki-67 antigen (MIB-1) showed a strong positive association with EGFR (P = 0.002) and an inverse correlation with ErbB2, ErbB3 or ErbB4 (P = 0.0004, 0.0000, and 0.001, respectively). With regard to carcinoma, there was no important relationship between receptor overexpression and tumour grading (P > 0.1), while only EGFR overexpression was correlated with muscular invasion (P = 0.02). Coexpression of EGFR-ErbB3 and ErbB3-ErbB4 was more often detected in high-grade tumours and correlated with the extent of tumour invasion. Our data indicate that class I receptors are differentially expressed in normal urothelium in vivo, but an orchestrated expression pattern does not exist during tumorigenesis.

Prognostic factors of primary transitional cell carcinoma of the upper urinary tract

OBJECTIVES We presented and analyzed our results in order to determine the relationship between patient survival and tumor grade and/or stage. In addition, a retrospective tumor DNA ploidy study was done to evaluate its possible role in predicting future tumor recurrence in the bladder. METHODS A total of 112 patients with upper urinary tract transitional cell carcinomas (TCCs) were recorded at our hospital. Of these, 68 patients without concurrent bladder tumors (ages ranged from 36 to 80, mean 62.4 years; male:female = 1:1.2) were treated by nephroureterectomy and bladder cuff resection. They were followed up for 14-79 months (average 38.2 months). Eight (36.4%) of the 22 patients who had stage C or D tumors had received adjuvant systemic methotrexate, vinblastine, epirubicin, cisplatin chemotherapy after surgery. DNA flow cytometry using paraffin-blocked tumor specimens was performed on the tumors of 52 patients. RESULTS Their pathologic stages and grades were 11 at stage 0, 15 at stage A, 20 at stage B, 14 at stage C, 8 at stage D; 9 of grade I, 41 of grade II, and 18 of grade III. Postoperatively, 13 patients (19.1%) subsequently developed bladder tumors with a latent period ranging from 2 to 37 months (average 14.9 months). The difference of the tumor DNA ploidy distribution pattern among tumors of high versus low stages and/or grades is not statistically significant (p > 0.05). Overall, the 5-year survival rates for patients with low- and high-stage tumors were 100 and 66.7%, respectively; for patients with grade I-II and III tumors they were 93.6 and 28.3%, respectively. CONCLUSIONS Patient survival was mainly related to both tumor stages (p = 0.0037) and grades (p = 0.0001), rather than to tumor DNA ploidy. For patients with grade II upper urinary tract tumors, tumor DNA ploidy seems to provide no additional predictive value on subsequent tumor recurrence in the bladder.

EPS8 Facilitates Cellular Growth and Motility of Colon Cancer Cells by Increasing the Expression and Activity of Focal Adhesion Kinase

In an attempt to study the role of Eps8 in human carcinogenesis, we observe that ectopic overexpression of Eps8 in SW480 cells (low Eps8 expression) increases cell proliferation. By contrast, expressing eps8 small interference RNA in SW620 and WiDr cells (high Eps8 expression) reduces their proliferation rate. Interestingly, attenuation of Eps8 decreases Src Pi-Tyr-416, Shc Pi-Tyr-317, and serum-induced FAK Pi-Tyr-397 and Pi-Tyr-861. Remarkably, by virtue of mammalian target of rapamycin/STAT3 Pi-Ser-727, Eps8 modulates FAK expression required for cell proliferation. Within 62% of colorectal tumor specimens examined, >2-fold enhancement of Eps8 as compared with their normal counterparts is observed, especially for those from the advanced stage. In agreement with the modulation of FAK by Eps8, the concomitant expression of these two proteins in tumor specimens is observed. Notably, Eps8 attenuation also impedes the motility of SW620 and WiDr cells, which can be rescued by ectopically expressed FAK. This finding discloses the indispensability of Eps8 and FAK in cell locomotion. These results provide a novel mechanism for Eps8-mediated FAK expression and activation in colon cancer cells.

Genetic Alterations in Urinary Bladder Carcinosarcoma: Evidence of a Common Clonal Origin

The cellular origin of carcinosarcoma of the bladder is unknown. We addressed this issue by using microsatellite analysis for loss of heterozygosity (LOH) in both the carcinomatous and sarcomatous components of 6 bladder tumors. We tested 40 microsatellite markers from 19 human chromosomes and compared the genetic alterations between the two separately isolated components. The potential relevance of the E–cadherin pathway was also evaluated by immunohistochemistry. All 6 cases revealed identical LOH on chromosomal arms 9p, 9q, 8p, and 8q, corresponding to relatively early events in bladder carcinogenesis. Discordant losses between two alleles in the remaining chromosomes, associated with progression, were seen in all tumors with a trend toward a higher incidence in the more advanced tumors (N1M1 and N1Mx). E–cadherin was strongly expressed in the carcinomatous components (5 of 6), whereas most of sarcomatous elements displayed absence of the protein product (4 of 6). These results indicate that both the carcinomatous and sarcomatous components of carcinosarcoma are derived from a common stem cell. Downregulation of E–cadherin may define one of the pathways responsible for conversion of epithelial cells to the sarcomatous phenotype.

Transcriptional activation of the Axl and PDGFR-α by c-Met through a ras- and Src-independent mechanism in human bladder cancer.

BackgroundA cross-talk between different receptor tyrosine kinases (RTKs) plays an important role in the pathogenesis of human cancers.MethodsBoth NIH-Met5 and T24-Met3 cell lines harboring an inducible human c-Met gene were established. C-Met-related RTKs were screened by RTK microarray analysis. The cross-talk of RTKs was demonstrated by Western blotting and confirmed by small interfering RNA (siRNA) silencing, followed by elucidation of the underlying mechanism. The impact of this cross-talk on biological function was demonstrated by Trans-well migration assay. Finally, the potential clinical importance was examined in a cohort of 65 cases of locally advanced and metastatic bladder cancer patients.ResultsA positive association of Axl or platelet-derived growth factor receptor-alpha (PDGFR-α) with c-Met expression was demonstrated at translational level, and confirmed by specific siRNA knock-down. The transactivation of c-Met on Axl or PDGFR-α in vitro was through a ras- and Src-independent activation of mitogen-activated protein kinase/extracellular signal-regulated kinase (MEK/ERK) pathway. In human bladder cancer, co-expression of these RTKs was associated with poor patient survival (p < 0.05), and overexpression of c-Met/Axl/PDGFR-α or c-Met alone showed the most significant correlation with poor survival (p < 0.01).ConclusionsIn addition to c-Met, the cross-talk with Axl and/or PDGFR-α also contributes to the progression of human bladder cancer. Evaluation of Axl and PDGFR-α expression status may identify a subset of c-Met-positive bladder cancer patients who may require co-targeting therapy.

The Prognostic Significance of RON and MET Receptor Coexpression in Patients with Colorectal Cancer

PurposeAlthough Recepteur d’Origine Nantais (RON), a member of the MET receptor tyrosine kinase family, is overexpressed and constitutively active in some primary tumors and tumor cell lines, its expression pattern and clinical significance in colorectal cancer are not well documented.MethodsBy using immunohistochemical staining, we examined RON and MET expression in 135 colorectal cancer specimens and investigated the association of the immunoreactivity of both receptors with colorectal cancer clinical parameters and prognosis.ResultsWe found moderate to strong expression in 99 cases (73 percent) for RON and 97 cases (72 percent) for MET. Univariate analysis showed that increased immunoreactivity of RON or MET was associated with shorter patient survival and that moderate to strong coexpression of both receptors was associated with a significantly worse prognosis. Multivariate Cox analysis showed that the risk of tumor recurrence for patients with high-RON/high-MET expression was approximately 11 times greater than for patients with low-RON/low-MET expression (P = 0.001). In addition, RON and MET expression levels were positively correlated (P ≤ 0.001; τ = 0.306).ConclusionsThe crosstalk between RON and MET in colorectal cancer seems important. Evaluating the expression patterns of RON and MET was predictive of clinical outcome for patients with colorectal cancer.