OBJECTIVE: To investigate the differences in the expression of phosphatase and tensin homologs (PTEN) and cyclooxygenase-2 (COX-2) of human chromosome 10 deletion of oncogenes in colorectal adenoma and carcinoma tissues. METHODS: The expression of PTEN and COX-2 proteins in 30 normal intestinal mucosa tissues, 30 non-adenomatous polyps, 60 adenomatous polyps and 30 intestinal cancer tissues were detected by immunohistochemical SP method, and their relationship with clinicopathological features and correlation between their expressions were analyzed. The positive expression rate of PTEN in normal intestinal mucosa, non-adenomatous polyps, adenomatous polyps and intestinal cancer tissues decreased gradually, and the positive expression rate in adenomatous polyps and intestinal cancer tissues was significantly lower than that in normal intestinal mucosa and non-adenomatous polyps tissues, and the difference was statistically significant (P<0.05). The positive expression rate of COX-2 in adenomatous polyps and intestinal cancer tissues was significantly higher than that in normal intestinal mucosa, and the positive expression rate of COX-2 in intestinal cancer tissues was significantly higher than that in non-adenomatous polyps, and the differences were statistically significant (P<0.05), In adenomatous polyps with high-grade intraepithelial neoplasia and carcinoma, the PTEN positivity rate was lower than that of early adenomas, and the differences were statistically significant (P<0.05); in adenomatous polyps, the COX-2 positivity rate was higher than that of those with diameter ≥1 cm, and the COX-2 positivity rate was higher in villous adenomas than that of tubular adenomas. The differences were statistically significant (p<0.05); the expression of pten and cox-2 in adenomatous polyps and intestinal cancer tissues were negatively correlated (p<0.05). < span=""> CONCLUSIONS: PTEN and COX-2 may jointly participate in colorectal adenoma carcinogenesis and play an important negative synergistic role; combined detection may predict adenoma carcinogenesis, and has some reference value for early diagnosis, treatment and prognostic assessment of adenoma carcinogenesis.