Abstract: BACKGROUND＆AIM: To study the relationship between serum P53 antibody, gene mutation,protein expression and their roles in the early diagnosis and clinical significance in colorectal tumors. MATERIAL AND METHODS: P53 antibody of preoperative serum from 34 patients with colorectal cancer and 10 healthy persons was measured by enzyme-linked immunosorbent assay (ELISA). At the same time, by using polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) and immunohistochemistry (IHC) (S-P methods), the mutations in exon 5－8 of the P53 gene and protein expression were examined. RESULTS: P53 antibody was positive in 6 of 34 (17.6％) patients with colorectal cancers, but was not found in serum of normal controls. The mutation of exon 5－8 and protein expression of P53 gene were found in 18 of 34(52.9％) and 19 of 34(55.9％) cases, respectively. No mutation and protein expression were positive in normal mucosa. Of 16 patients who were positive for P53 gene mutation in their tumor tissue, 7(43.8％) had evidence of alterations in the P53 gene within the stool. No relationship was found between P53 antibody, protein expression, P53 gene mutation and cliniopathological factors. CONCLUSION: Our data indicate that mutation of P53 gene was one of the main factors which caused its protein expression,hence inducing serum P53 antibody formation. P53 gene mutation could be detected within the stools. Detection of P53 serum antibody and gene mutation in stool may provide new ways for the early diagnosis and survey of population at high risk of colorectal cancers.

Key words: colorectal neplasms;gene;P53;polymerase chain reaction;Enzymed-linked immunosorbent assay, immunohistochemistry