Codon 201 Mutation of DCC Gene and Tumor Biologic Behavior in Human Colorectal Carcinoma

Objective To explore the relationship between a point mutation of codon 201 in deleted in colorectal carcinoma ( DCC) gene and the biological behavior of colorectal carcinoma. Methods Tumor tissues and matched adjacent normal colon mucosa collected in 35 patients during surgical resection for colorectal carcinoma were analyzed. Forty normal colon mucosa tissues obtained by biopsy from patients who had neither colorectal tumor nor a family history of colorectal cancer during colonscop ic examination were used as control. Codon 201 mutatian was detected with allele-specific PCR and a restriction enzyme digestion method. The tumors were reviewed as clinical data, tumor location, histology,metastasis, and pathological staging (Dukes classification). Results The frequency of mutation at codon 201 in tumor tissue and corresponding adjacent normal mucosa was 71.4 % and 60 %, respectively, and either of the rates was significantly higher than that of normal control(32.5 % ). The point mutation rate in tumor tissues did not differ from that in the corresponding normal adjacent tissues. Statistic analysis showed that the mutation rate had no relationship to the sex, age of the patients, the histological pattern , differentiation, and invasion depth of the tumors. However, 93. 8 % of the mutation rate in colorectal cancer with lymph node invasion and/or distant metastasis is significantly higher than 52. 6 % of mutant rate in colorectal cancer uithout lymph nodes invasion or metastasis ( P ＜0. 05). Conclusion The point mutation at codon 201 of DCC gene is an early genetic event in colorectal cancer, and play some role in invasion and metastasis of colorectal carcinoma. It may serve as a useful genetic marker for identifying higher risk patients with colorectal carcinoma.