AN IMMUNOHISTOLOGIC STUDY ON KI67, P53, P21 AND CEA EXPRESSION IN COLORECTAL CARCINOGENESIS

The immunohistological expression for Ki67, p53, p21 and CEA was studied in 10 normal colonic mucosa, 18 adenomas, 13 ca in adenomas, 12 sm cancers and 39 advanced cancers, respectively. In normal mucosa, Ki67 staining cells were topographically expressed in the crypts. Both p21 and CEA were inversely expressed in the upper crypts. On the other hand, p53 could not be detected. This topographic expression was abrogated in all examined tumors. The immunoreactivity was positively correlated with the progression of the tumor during normal→adenoma carcinoma sequence. The immunoreactivity for p21 expression tended to decrease in relation to the progress of malignancy. Cellular CEA expression showed apical cell membrane staining in the normal mucosa, but abnormal cellular CEA staining patterns such as depolarized cytoplasmic staining and extra stromal staining tended to increase during the progression of malignant transformation. These results indicate that loss of normal topographic expression and alteration of immunoreactivity may play an important role in colorectal oncogenesis.