Genetic instability of D1S468 loci of p73 gene and its relationship with clinical pathological features in patients with colon cancers

Objective To examine loss of heterozygosity (LOH), microsatellite instability (MSI) of locus D1S468 on chromosome 1 and to identify the role of the genetic instability of p73 gene in the development of colon cancer and discuss the relationship between the genetic instability and the pathological features of colon cancer. Methods Tumors and paired normal tissues from 76 cases of colon cancers were obtained from formalin-fixed paraffin-embedded tissues. DNA was extracted by phenol-chloroform extraction. Polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) was performed to expand D1S468 loci of p73 gene. Autoradiography was used to investigate the genetic instability (LOH and MIS). Results In this experiment, the frequency of LOH, MIS in 53 cases of colon cancer was 45.3% and 17.0% respectively, which was significantly higher than in normal tissue. The frequency of LOH in colon cancer was associated with the degrees of pathological differentiation, Dukes stages and lymph node metastasis. The frequency of MIS in colon cancer was associated with the site of the tumor, histological type of tumor, and lymph node metastasis. Conclusion MSI and LOH may regulate the development of colon carcinoma through different ways. MIS of colon cancer occur in the early stage mainly may be related to the occurrence of colon carcinoma and be expected to become the diagnostic molecular marker of early stage colon cancer. Meanwhile, LOH may participate in progression and worsening of cancer, and play the role of promoting lymph node metastasis. Key words: Colon cancer; Loss of heterozygosity; Microsatellite instability; p73 gene