NGB and colorectal carcinoma: A search of The University of ALabama at Birmingham CANcer data analysis Portal [20, 21] (UALCAN, http://ualcan.path.uab.edu/) showed that the expression of NGB is lower in CRC samples than in adjacent tissues (Fig. 1A left, Additional file 1: Fig. S1A), while the methylation status of NGB is higher (Fig. 1A right).