With regard to copy number alteration (CNA), colorectal NECs usually had CNA frequently in chromosomes 8, 9, 13, 16, 17, and 20 with a gain of MYC (12.3%), loss of RB1 (10.7%), and loss of PTEN (5.4%) being the most common CNAs, while colorectal NETs often had the most CNAs occurring in chromosomes 3, 9, 11, 12, 17, and 18 with a low CNA frequency [28]. This evidence concerns the gene RB1 and colorectal neuroendocrine tumor.