Role and prognostic significance of p53 mutation in colorectal carcinomas

Abstract

AIM: To study the prognostic significance of the p53 cDNA mutation and mutant p53 protein in colorectal adenocarcinomas.

METHODS: p53 cDNA mutaiton was detected with RT-PCR-SSCP, and mutant p53 protein overexpression was detected by PAb 240 monoclonal antibody in 100 cases of colorectal adenocarcinomas. The follow up survey of all patients were done within the five years after operation, and comparing with p53 cDNA mutation and mutant p53 protein overexpression for the prognostic significance of colorectal adenocarcinomas. The data is treated with SPSS computer program, Kaplan Meier Survival Plots were calculated and analyzed by Log-rank analysis.

RESULTS: Fifty-one cases of p53 cDNA mutations (51%) were found with RT-PCR-SSCP and 76 cases of mutant p53 protein overexpression (76%) found with PAb 240 monoclonal antibody immunohistochemistry staining in 100 cases of colorectal adenocarcinomas. There are no relationship with Dukes stage in the statistics in p53 cDNA mutation (mutation: Dukes A 9%, B 10%, C 20%, D 12%; No mutation: A 13%, B 12%, C 12%, D 12%) and mutant p53 protein overexpression (positive: Dukes A 17%, B 6%, C 27%, D 16%; negative: A 5%, B 6%, C 5%, D 8%) (P < 0.05). Moreover, the data show p53 cDNA mutation is associated with mutant p53 protein overexpression (both positive 49%, single positive 29%, both negative 22%) (P < 0.01), p53 cDNA mutation can provide prognostic information (p53 cDNA mutation positive: alive 35, dead 16; negative: alive 42, dead 7) (P < 0.05), and mutant p53 protein overexpression is ambiguous and does not assess prognosis (p53 protein overexpression positive: alive 58, dead 18; negative: alive 19, dead 5) (P = 0.72)with Kaplan Meier Survival Plots and Log-rank analysis.

CONCLUSION: p53 cDNA mutation is associated with mutant p53 protein overexpression (p53 cDNA mutation and mutant p53 protein overexpression both positive 49%, single positive 29%, both negative 22%) (P < 0.01) and p53 cDNA mutation can provide poor prognostic information, and is the biomarker of poor survival of colon cancer. However, mutant p53 protein overexpression could not predict prognosis and may be effected by other multi-factors in colon cancer.

Key Words: Colorectal neoplasm; Genes, p53; Gene expression; Polymerase chain reaction; Mutation; Immunohistochemistry