PMS2 and malignant colon neoplasm: In addition, 27 tissue samples obtained as samples of colon cancers had marginal tissue attached with histologically normal colonic morphology that were observed after the "colon cancer samples" were cut in triplicate and immunostained for Pms2, Ercc1 and Xpf, and 3 such tissue samples were cut and immunostained for Ku86.