ESR1 and gastric cancer: In circulation, Vickers et al. [54] have found miR-188-5p to be highly abundant in high density lipoproteins and circulating levels of miR-222-3p have been demonstrated to be a useful diagnostic marker in gastric cancer; and miR-222-3p has been reported to negatively regulate the expression of ERα in endometrial carcinoma cells [55], but oestrogen-mediated regulation of miR-222-3p and miR-188-5p have not been previously reported.