Influence of Apoptosis Related Protein for Carcinogenesis of Colorectal Adenoma Evaluated by Immunohistochemical Stain

Masahiro Katada, Yasuyuki Sugiyama, Katsuyuki Kunieda and Shigetoyo Saji

Second Department of Surgery, Gifu University School of Medicine

The expression of mutant p53, bcl-2 and the apoptotic index (AI) was investigated by immunohistochemical stain in a total of 174 colorectal tubular adenomas obtained from endoscopic polypectomy. The following results were obtained. The positive expression of bcl-2 was significantly higher in tubular adenoma with moderate atypia in comparison with mild atypia, while it slightly decreased in early cancer. The positive expression of mutant p53 increased in proportion to the degree of atypia of the adenoma and was highest in early cancer. AI value was significantly lower in tubular adenoma with mild stypia, moderate atypia, severe atypia, early cancer than in normal tissues. The both positive expression of both p53 and bcl-2 were significantly higher in tubular adenomas more than 6 mm in size and in the shape of I sp and I p.
1) From the above results, it is suggested that bcl-2 and mutant p53 probably play an important role in the early and late stages of the adenoma-carcinoma sequence. 2) Moreover, tubular adenomas with more than moderate atypia, of more than 6 mm and pedunculated, should have a high malignant potential.

Key words
colorectal adenoma, mutant p53, Bcl-2 protein, TUNEL stain, apoptosis

Reprint requests
Masahiro Katada Second Department of Surgery, Gifu University School of Medicine 40 Tsukasamachi, Gifu, 500-8076 JAPAN

Accepted
April 28, 1999

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