H19 and ovarian cancer: Gao et al. [15] have pointed out that LncRNA H19 can act as a molecular ‘sponge’ for miR-let-7b, and in the regulation process of HOST2, the level of miR-let-7b was regulated, which inhibited the activity of let-7b and increased mRNAs and protein levels of high-mobility group including AT-hook 2 (HMGA2), c-Myc, Dicer and Imp3, thus inducing cell metastasis and invasion in ovarian cancer [15].