BDNF and colorectal carcinoma: Fourteen functional modules that may play important roles in the early detection of CRC were highlighted and the sub-network of hub genes KIT, SEMA7A, BDNF, MEF2A, LDB2, GATA4, LHX2, SOST, CTLA4, NKX2-2, TLE4, BMP5, NFATC1, ZFPM1, DPYSL2, and ITGA2B was extracted.