Sun W, Li S, Tang G, et al. - Researchers sought to determine the biological functions of human endogenous retrovirus-H long terminal repeat-associating protein 2 (HHLA2; a member of B7 family) in human non-small cell lung cancer (NSCLC) as well as the relevant mechanisms. They also investigated the impacts of tumor cell-derived HHLA2 on tumor-associated macrophage (TAM) polarization. Via colony formation and modified Boyden chamber assays, experts evaluated NSCLC cell growth, migration, and invasion. Upregulation of HHLA2 was found in A549 and H1299 cells (human NSCLC cell lines) vs the normal lung epithelial BEAS-2B cells. In vivo, inhibition of tumor growth resulted from knockdown of HHLA2. Findings revealed that NSCLC growth as well as TAM M2 polarization were inhibited by HHLA2 downregulation. In the light of these findings, HHLA2 may represent a treatment target as well as a promising prognostic biomarker in NSCLC.