CASC2 and osteosarcoma: For instance, Cao et al. [19] revealed that downregulation of lncRNA CASC2 by microRNA-21 increased the proliferation and migration of renal cell carcinoma cells; Zhang et al. [20] illustrated that Antisense lncRNA FOXC2-AS1 promoted doxorubicin resistance in osteosarcoma by increasing the expression of FOXC2; and Liu et al. [21] related that epigenetic silencing of miR-218 by the lncRNA CCAT1, acting via BMI1, promoted an altered cell cycle transition in the malignant transformation of HBE cells induced by cigarette smoke extract.