Immunohistochemical detection of receptor tyrosine kinases c-kit, EGF-R, and PDGF-R in colorectal adenocarcinomas.

ABSTRACT

PURPOSE: The selective inhibition of tyrosine kinases is a promising strategy in the treatment of several human malignancies. This study aimed to clarify expression patterns of therapeutically addressable receptor tyrosine kinases in colorectal cancer. MATERIALS AND METHODS: In this study, we used tissue arrays to analyze 263 specimen of colorectal carcinoma for the expression of the tyrosine kinases c-kit (CD117), epidermal growth factor receptor (EGF-R), and platelet-derived growth factor receptor (PDGF-R). Staining patterns were then correlated with tumor stage and survival. RESULTS: Five tumors (1.9%) showed a strong expression of c-kit (CD117), while in 40 samples (15.2%), a weak/intermediate expression was observed. Positive staining did not correlate with histopathological parameters although a trend toward a better survival of c-kit-positive patients was observed. No positivity for PDGF-R was observed in 263 samples of colorectal carcinomas. Positive EGF-R expression was identified in 39 cases (15.2%), whereas 218 samples (84.8%) stained negative. CONCLUSIONS: Our study confirms that expression of the tyrosine kinases c-kit and PDGF-R are rare in colorectal carcinomas and do not correlate with tumor stage.