Expression of mutant p53 and of the multidrug resistant proteins P-glycoprotein and glutathione S-transferase-pi correlated in colorectal adenocarcinoma.

Accumulating studies suggest that multidrug resistance is related to expression of p53, P-glycoprotein (Pgp) and Glutathione S-Transferase-pi (GST-pi). This study was to estimate mutant p53 expression and its correlation with drug resistance related proteins Pgp and GST-pi expression in colorectal adenocarcinoma patients. Immunohistochemical ABC technique was used to detect the expression of mutant p53 protein, Pgp and GST-pi in 404 cases with colorectal adenocarcinoma. A low frequency of mutant p53 accumulation was observed, consistent with findings in colorectal cancers (CRCs) from other Asian populations. Accumulation of mutant p53 was related to AJCC staging (p < 0.05). Pgp expression was significantly correlated with tumor location (p = 0.039) and gender (p = 0.043). The positive percentage of Pgp and GST-pi expression was all significantly higher in mutant p53 protein positive group than mutant p53 protein negative cases (r = 0.634, p < 0.001 and r = 0.680, p < 0.001, respectively). These findings demonstrate association of three biomarkers with clinicopathologic parameters of colorectal carcinoma, and overexpression of Pgp and GST-pi was closely correlated with mutant p53.