Correlation Study Of Serum P53 Antibody, P53 Protein Overexpression And Clinicopathological Characteristics In Colorectal Cancer

Colorectal cancer, one of the most common malignancies worldwide , contains P53 alterations in about 60% ~ 70% of cases. DNA sequencing is the gold - standard method, but it is not feasible on a routine clinical basis. Immunohistochemistry is the most widely used method for assessing P53 alterations in human cancers. But some mutations may not lead to P53 protein accumulation, or P53 overexpression may be detected in the absence of mutations of P53 gene. Compared with the methods cited above, serological detection of p53 - Ab is easier to perform, does not require tumor material and is of potential interest in clinical practice. The aims of our study were to ( 1) assess the correlation between serum p53 antibody and P53 protein expression in colorectal cancer, (2) analyze the correlation between serum p53 antibody and clinicopathological characteristics in colorectal cancer, (3 ) determine whether serum p53 antibody has significant clinical value as a new tumor marker.MethodsOne hundred and thirty - two cases with colorectal adenocarcino-ma were included in the present study who were performed surgical resection in Kanazawa Medical University of Japan from April, 2002 to January, 2003. Thirty - six non - tumor cases also joined in this prospective study as control Group. The presence of serum p53 antibody was determined by enzyme - linked immunosorbent assay ( ELJSA) . Serum CEA and CA19 - 9 were examined by radioimmunoassay ( RIA). Immunohistochemical analysis of tumors was performed to detect the accumulation of P53 protein. For all statistical analyses, Stat-View version 5. 0.1 software (SAS Institute Inc) was used. The probability of less than 5% was assumed to be statistically significant ( P < 0.05).ResultsThe positive rate of p53 antibody was 40. 2% in patients with colorectal cancer, and 2. 9% in control group, P<0.0001. Although the positive rate of CEA and CA19 -9 were 18. 2% and 12. 9% in colorectal cancer Group, the difference had no significance compared with control Group. Fifty - one (96.2% ) of serological positive colorectal cancer patients had the overexpression of P53 protein, whereas only 24 cases (30. 4% ) had positive staining of P53 protein in patients with negative serum p53 antibody ( P < 0.0001). The presence of serum p53 antibody had no relation to age or gender of colorectal cancer patients, as well as tumor size, location and growth type. There was significant difference in the prevalence of p53 antibody in patients with liver metastasis (75% vs37% ) or lymph node metastasis (52% vs 33% ) when compared to those without tumor spread. The serum p53 antibody was also noticed to be more common in poorly dif-ferentiated cancer, P = 0. 0007. The presence of p53 antibody was found in all Duke's stages, which was 14% in Duke's A, 30% in Duke's B, 44% in Duke's C, 78% in Duke's D, P =0.0013. Thirty - nine (74% ) of p53 seropositive patients showed negative conversion one month after operation, which were 82% in radical resection Group and 33% in palliative operation Group (P =0.0026).ConclusionTesting of serum p53 antibody is a feasible technique for assessing alterations of P53 gene in colorectal cancer. Serum p53 antibody appears to be a new tumor marker, and detecting of serum p53 antibody is expected to be a useful method of early diagnosis for colorectal cancer mass screening. The analysis of serum p53 antibody may be of value for the postoperative monitoring of colorectal cancer.