The expression of LC-3 is related to tumor suppression through angiogenesis in esophageal cancer

Autophagy is important in the development and remodeling of cells. It is required for cellular adaptation to nutrient deprivation and elimination of damaged organelles. Recently, autophagy has been implicated in carcinogenesis and metastasis. We hypothesized that autophagy-related proteins are initiated until nutrition is supplied by angiogenesis. We evaluated the clinicopathological significance of LC3, an autophagic marker, and its relationship to angiogenesis in patients with esophageal squamous cell carcinoma (ESCC). We immunohistochemically investigated the expression of LC3 as well as endoglin (CD105), a microvessel marker, and vascular endothelial growth factor A (VEGF-A) in 142 patients with ESCC. The high, moderate, and low expression rates of LC3 were 40, 31, and 29 %. LC3 expression inversely correlated with depth of invasion, lymph node metastasis, lymphatic invasion, MVD, VEGF-A expression, and poor prognosis. The overall survival rate was better in patients with high LC3 expression compared to patients with low LC3 expression. We demonstrate that low LC3 expression is related to tumor development as facilitated by angiogenesis and that alteration in LC3 expression is closely related to prognosis. Expression of LC3 proteins is a useful marker for determining tumor prognostic behavior in patients with ESCC.