The monoclonal antibody MC_3 related antigen was expressed in colon carcinoma, its transitional mucosa, colon polyp and fetal colon mucosa with immunohistochemical staining.The positive rate was 95.38%,47.00%,70.83%, 65.08%, 69.23%, 42.00%, and 37.50% in colon carcinoma, transitional mucosa, fetal colon mucosa, familial polyp, villus adenoma, tubular adenoma and infantile polyp respectively. Moreover, the positive rate became higher as the proli-ferative grading of polyps was larger.The findings suggest that monoclonal antibody MC_3 can be used as a means to detect the possible cancerous degeneration of colon polyps and transitional mucosa of the colon can be considered as a precancerous lesion.

Two hundred specimens of the "transitional mucosa" of colorectal carcinoma were studied with mucohistochemical methods of HID/AB and PAT/KOH/PAS,immunohistochemical methods of MC3,CEA,lectin receptor PNA,UEA-1 and DBA,and scanning electron microscopy.10 specimens of normal colonic mucosa.130 specimens of colorectal carcinoma,155 specimens of various types of colorectal adenoma and polyp,and 24 sepcimens of normal colonic mucosa of fetus aged 3 to 5 months were also examined to serve as controls.It was found that in every stage of the malignant deterioration of the colorectal mucosa,there was significant difference between the mucohistochemical changes and the immunohistochemical changes(P

The clinical and pathological materials of 83 cases of prostatic carcinoma (PC) were reviewed retrospectively and the tissue specimens of PC were marked with prostate-specific antigen (PSA). According to the criteria of Dhom's classification of prostatic carcinoma. 66 cases out of the 83 (79. 5%) were of the common variety of PC, 14 cases (10. 9%) were of the rare variety and 3 cases (3. 6%) could not be classified with Dhom's method. Among the 66 cases of common prostatic carcinoma, 41 cases (49. 4%) exhibited a pathological structure of u-riiforrn pattern and 25 cases (30. 1%) of pluriform pattern. Well-differentiated adenocarcinoma, cribriform carcinoma and carcinoid of the prostate were strongly positive to PSA marking; poorly-differentiated adenocarcinoma and almost all the prostatic carcinomas of the rare variety and with the structure of pluriform pattern were positive or weakly positive; undifferentiated solid carcinoma and small cell carcinoma were very weakly positive; and squamous cell carcinoma was negative. In addition, other methods for the pathological classification of prostatic carcinoma used currently at home and abroad were compared and discussed.