Immunohistochemical phenotype of colorectal carcinoma in patients with KRAS mutation and mismatch repair status

Introduction : Aberrant expression of CK7/CK20/CDX2 is reported in percentage colorectal carcinomas (CRC). Aim The objective this study was to investigate specific morphological and immunohistochemical characteristics carcinoma with KRAS mutation status microsatellite instability. Materials methods Seventy-one patients CRC examined were included the investigation. Immunohistochemistry performed using antibodies CK7, CK20, CDX2, PMS2, MSH6. An automatic immunostainer (Ventana BenchMark GX) used following manufacturer’ instructions. Fisher’s exact test for statistical analysis ( p value <0.05). Results Immunohistochemical typical profile observed 50% cases. highest sensitivity specificity established 93% cases demonstrating positive nuclear tumor cells. As status, 20% cancers showed loss one or both mismatch repair proteins - PMS2 MSH6, which associated CK20 CDX2 as well. Downhill correlation found also between presence gene KRAS. Conclusions Our results may support heterogeneity carcinoma. Statistically significant deficient mutant cancers. This lead application screening panel selection genetic testing. Further studies on large cohorts correlating different profiles molecular subtypes are needed better understanding pathogenesis behavior