The characteristics of ductal adenocarcinoma of colon under eieciror: microscopy were stout and dense microvill, with small roots buried in the top of cytoplasm. The ullrarnorphological changes of carcinomatous infiltration was similar to the picture observed in vitro cultivation of cancer cells.In 104 cases out of 159, there was an over expression of ras oncogenes P21, indicating that carcinoma of colon was related to activation of ras oncogenes. Examination with monoclonal antibodies yielded a positive rate of 83.4%- 95.7%, indicating that most of the carcinomas had colon related antigens. This phenomenon should play an important role in raising the diagnostic accuracy, and it also should serve as an indicator of effective treatment. In 62 cases of mucoid adenocarcinoma and 30 cases of signet ring cell carcinoma, there was a marked reduction of mueoitin sulfate with an increase in sialic acid mucus. The letter was a glycoprotein containing hydroxyl mucus, and it facilitated the separation of cancer cells to infiltrate and metastasize.in 134 cases, AgNOR was quantified, and there were 13.05? 1.48 granules in each mucleas. There was more abundant AgNOR in undifferentiated cancer, while the number of AgNOR fluctuated between 10.56 to 11.83 in papillary adenocarcinoma, ductal adenocarcinoma, and mucoid adenocarcinoma. indicating the qunantity of AgNOR was related to degree of malignancy in colonic carcinoma.