Nuclear β-catenin expression as a prognostic factor in advanced colorectal carcinoma

AIM： To investigate the changing pattern of β-catenin expression and its prognostic value in advanced colorectal cancer （CRC）. METHODS： Archival tumor samples were analyzed for β-catenin using immunohistochemistry （IHC） in 95 patients with advanced CRC. RESULTS： Membranous β-catenin expression was found in the normal colorectal epithelium. Almost 100% of CRC cases showed membranous and cytoplasmic expression, and 55 （58%） cases showed nuclear expression. In univariate （Kaplan-Meier） survival analysis, only the nuclear index （NI） was a significant predictor of disease free survival （DFS） （P = 0.023; n = 35）, with a NI above the median associated with longer DFS （34.2 too） than those with a NI below the median （15.5 too） （P = 0.045, ANOVA）. The other indices were not significant predictors of DFS, and none of the three tested indices （for membranous, cytoplasmic, or nuclear expression） predicted diseasespecific survival （DSS）. However, when dichotomized as positive or negative nuclear expression, the former was a significant predictor of more favorable DFS （P = 0.041） and DSS （P = 0.046）. CONCLUSION： Nuclear β-catenin expression provides additional information in predicting patient outcome in advanced CRC.

Up-regulation of α-catenin is associated with increased lymph node involvement in colorectal cancer

AIM: To investigate the changing pattern of α-catenin expression and its relationship to clinical and pathological features of colorectal cancer (CRC) patients. METHODS: Archival tumor samples were analyzed using immunohistochemistry (IHC) for α-catenin in 91 patients with advanced CRC. RESULTS: The values of α-catenin membrane index (MI) and cytoplasmic index (CI) were significantly related to the depth of tumor invasion (P = 0.027, P = 0.020, respectively), high indices being associated with increased depth of the primary tumor invasion (T3 and T4). Similarly, patients with high α-catenin expression had a signifi cantly increased risk of lymph node metastasis (32/39 vs 37/52 for MI and 37/45 vs 32/46 for CI) (P = 0.001, P = 0.0001, respectively, for LNN status). An altered expression (i.e., cytoplasmic pattern) was also related (P = 0.047) to the response to chemotherapy; patients with low CI were more responsive (CR: 7/46) than patients with high CI values (CR: 0/45). There was a marginal effect on survival in patients time with metastases (SWM) (P = 0.087); patients with low CI showing slightly longerSWM, but no such effect on disease free survival (DFS) or disease specifi c survival (DSS). As to co-expression with another member of the adhesion complex (β-catenin), high α-catenin/β-catenin MI index was of marginal signifi cance in predicting longer DSS (P = 0.063, log-rank). CONCLUSION: The results implicate that high α-catenin expression is intimately involved in the key regulatory mechanisms leading to invasive phenotype, lymph node metastases, and progressive disease in CRC.