ABSTRACT
Background: Endoscopic submucosal dissection (ESD) has become the preferred treatment of early colorectal cancer. PDCD4 and autophagy have important clinical significance in the pathogenesis of colorectal cancer. Aims: To explore the expressions and significance of apoptosis factor PDCD4 and autophagy factors LC3Ⅱ and p62 in colorectal cancer. Methods: Fifty-four early colorectal adenocarcinoma patients treated by ESD from Jan. 2015 to Nov. 2020 at Binzhou Medical University Hospital were collected. The expressions of PDCD4, LC3Ⅱ and p62 were detected by immunohistochemistry, and the correlations with clinicopathological factors were analyzed. The differential expression of PDCD4 in pan-cancer was analyzed by bioinformatics analysis. Results: Expression of PDCD4 was associated with the long-diameter of paracancer adenoma (P<0.05), and expressions of LC3Ⅱ and p62 were associated with the long-diameters of adenocarcinoma and paracancer adenoma (P<0.05). The positive expression of PDCD4 in P-NIMM was located in the nucleus, while the positive expression in adenocarcinoma was located in cytoplasm. The nucleus/cytoplasm ratio of PDCD4 was significantly higher in P-NIMM than in P-LGIN, P-HGIN and adenocarcinoma (P<0.05), and the nucleus/cytoplasm ratio of PDCD4 was significantly higher in P-LGIN, P-HGIN than in adenocarcinoma (P<0.05). The positive expression rates of LC3Ⅱ and p62 were significantly higher in adenocarcinoma than in P-NIMM and P-LGIN (P<0.05). In P-LGIN, P-HGIN and adenocarcinoma, the expression of PDCD4 was negatively correlated with the expressions of LC3Ⅱ and p62 (P<0.05). The bioinformatics analysis showed that expression of PDCD4 was significantly reduced in a variety of malignant tumors including colorectal cancer (P<0.05). Conclusions: The inhibition of apoptosis and activation of autophagy may promote the occurrence of colorectal cancer, and its mechanism may be related to the intracellular transposition of PDCD4 that inhibits cell apoptosis and enhances autophagy, and activating cellular autophagy may further accelerate the degradation of PDCD4 and thus reducing its cancer inhibiting effect.