GREM1 and colorectal carcinoma: GWAS have identified several genomic regions associated with the risk of CRC and these genomic regions include genes in the TGF-β signaling pathway such as SMAD7,44,55BMP2,26,33,56BMP4,26,56 and GREM1. 26,57 Phipps et al58 found that rs4939827, located in SMAD7 intron 4, was significantly associated with poorer overall survival status of patients and disease-specific survival status.