LC3 overexpression in colorectal cancer – strong correlation with M1 tumor-associated macrophages: An observational study

This study evaluates the levels of light chain 3 (LC3) expression and tumor-associated macrophage (TAM) infiltration in colorectal cancer (CRC). This was a retrospective, observational study. Immune cell infiltration in colon adenocarcinoma samples was analyzed using the Gene Expression Omnibus database. Immunohistochemistry was used to detect the expression of LC3, CD4, CD8, CD20, CD16, CD163, and CD68 in CRC tissues. Expression differences of these markers and their relationships with patient clinicopathological features and prognosis were analyzed. CD4+ memory T cells were positively correlated with M1 macrophages M1. Levels of LC3 expression, M1-TAMs, and M2-TAMs were greater in CRC samples than in normal tissues. High LC3 expression levels were positively correlated with M1-TAMs and negatively correlated with M2-TAMs. Compared with tumor-infiltrating CD4+, CD8+, and CD20+ lymphocytes, the positive correlation between LC3 and M1-TAMs was more significant. M2-TAMs were negatively correlated with tumor-infiltrating CD4+, CD8+, and CD20+ lymphocytes. Levels of LC3 expression, M1-TAMs, and M2-TAMs were closely related to tumor size, invasion, lymph node metastasis, and CRC patient prognosis. High levels of autophagy may recruit macrophages to promote M1-TAM aggregation and induce immune cell aggregation. Autophagy is therefore a regulator of macrophage polarization and could be regulated to enhance antitumor immunity.