HHLA2 and neoplasm: Genes, including RELT, TNFSF14, TNFRSF1A, HHLA2, TNFRSF25, TNFSF4, TNFRSF6B, LTBR, and TNFRSF10A had high expression levels, and TNFRSF19 and TNFSF15 had low expression levels in tumor tissues compared with normal tissues.