CXCL12 and neoplasm: Third, clinical (PCR, immunohistochemistry, and Pearson's correlation), in vitro (coimmunoprecipitation, knockdown, overexpression, or coincubation of immune cells), and in vivo (tumor transplantation, mimics, siRNA transfection, and immunotherapy) experiments should be conducted to explore the PPI relationships between our signature genes (PRPH-PTN, ASB2-CASQ2/PDK4/EPHA67, and GPR15/TCL1A-CXCL12) and assess the functions of our signature genes in the progression of RC (especially RNASE7, which was not reported in CRC previously).