Expressions of maspin, P53 and Skp2 in colorectal tumors and their clinicopathological significance

To investigate the role of maspin, p53 and Skp2 expressions in the progression of colorectal tumors, and their clinicopathological significance. The expressions of maspin, p53 and Skp2 in colorectal adenocarcinoma (n=50), adenoma (n=20) and normal tissue (n=20) were detected by immunohistochemistry and compared with the clinicopathological tumor parameters. The relationship among maspin, p53 and Skp2 expression was also analyzed in colorectal tumors. The reverse transcriptase PCR was carried out to detect the level of maspin mRNA from 31 colorectal adenocarcinoma and 10 normal control tissues. Of 50 cases of colorectal adenocarcinoma, the positive expression rates for maspin, p53 and Skp2 in colorectal adenocarcinoma were 62% (31 of 50 cases), 50% (25 of 50 cases), 48%( 24 of 50 cases), respectively; The positive expression rates for maspin, p53 and Skp2 in adenoma were 90%, 5%, 5%, respectively; The positive expression rates for maspin, p53 and Skp2 in normal control were 95%, 5%, 5%, respectively. Maspin expression was much lower in colorectal adenocarcinoma than in adenoma and normal tissues (both P < 0.05). Maspin expression showed a negative association with lymphatic metastasis and higher Dukes' stage (both P < 0.05). Expression of maspin protein was negatively correlated with p53 expression (r =-0.536, P < 0.01, in adenocarcinoma; r=-0.668, P < 0.01, in adenoma). However, there was no significant correlation between expression of p53 and Skp2 (r=0.000, P > 0.05, in adenocarcinoma; r=-0.053, P > 0.05, in adenoma). Maspin might play an important role in tumorigenesis and progression (especially in lymph node metastasis) of colorectal adenocarcinoma. Maspin expression was inversely correlated with mutant p53 expression in colorectal tumors, which suggested that maspin expression was regulated by the p53 pathway. Skp2 might serve as an independent factor which participated in multistage process of colorectal carcinogenesis.