APLN and nonpapillary renal cell carcinoma: To further confirm the results of databases, 10 LR-pairs, including ‘APLNR_APLN,’ ‘CSF1R_CSF1’, ‘CX3CR1_CX3CL1’, ‘EPHA4_EFNB3’, ‘FGFR3_EPHA4’, ‘HGF_CD44’, ‘KDR_VEGFC,’ ‘NGF_NGFR,’ ‘TEK_ANGPT1’ and ‘TEK_ANGPT4’ were subjected to RT-qPCR assay in ccRCC cell line.