CCND1 and gastric cancer: Tumor suppressor miR-195-5p, miR-204, miR-623, miR-939 and miR-124 have been shown to be involved in overcoming 5-FU resistance of gastric cancer via silencing Zing finger 139 (ZNF139), TGFBR2, cyclin D1 (CCND1), solute carrier family 34 member 2 (SLC34A2) and EZH2, respectively [136–140].