TTN-AS1 and cancer: Several lncRNAs, such as metastasis-associated lung adenocarcinoma transcript 1, HOX transcript antisense RNA, TTN antisense RNA 1 (TTN-AS1), small nucleolar RNA host gene 6, and long intergenic non-protein coding RNA 1503 (LINC001503) have been demonstrated recently to be involved in the competitive endogenous RNA (ceRNA) network and regulate gene expression in several cancers, including CRC (Lu et al., 2018; Duan et al., 2019; Sun et al., 2019; Wang X. et al., 2019; Wang Y. et al., 2019; Yu et al., 2019).