Immunohistochemical Studies of Colorectal Cancers that Developed Following Pelvic Irradiation

Abstract

Radiation therapy is believed to be a predisposing factor in the development of carcinoma. During the period from 1974 to 1997, we treated five colorectal cancers in four patients who had undergone pelvic irradiation for cervical cancer. Radiation-induced changes in the remaining bowel were recognized in all of these patients. Of the five tumors, two were histologically diagnosed as mucinous adenocarcinoma, demonstrating a higher distribution than usual: To clarify the characteristics of the tumors, we examined the frequency of mutation in K-ras and p53 genes, and the proliferating cell nuclear antigen (PCNA) proliferation activity. The K-ras and PCNA stains did not show any clear characteristics of radiation-induced colorectal cancers in comparison with ordinary colorectal cancers; however, it was of interest that strongly positive staining was observed in our mucinous adenocarcinomas, even though a low frequency of p53 gene mutation has been reported in ordinary mucinous adenocarcinomas.

Detection of K-ras gene mutation by polymerase chain reaction/restriction fragment length polymorphism in Egyptian patients with colorectal cancer

“…Several authors have reported an association between the presence of a specific codon 12 K-ras gene mutation and the mucinous histotype in colorectal carcinomas (Nakao et al, 2000;Bazan et al, 2002) and in intestinal-type ovarian carcinomas (Gemignani et al, 2003). Several authors have reported an association between the presence of a specific codon 12 K-ras gene mutation and the mucinous histotype in colorectal carcinomas (Nakao et al, 2000;Bazan et al, 2002) and in intestinal-type ovarian carcinomas (Gemignani et al, 2003).…”