The intratumoral injection of an miR-199a-3p agomiR into G-292 indeed led to a decrease of the AK4 level in the tumor sections (Fig. 6d and e), which further confirmed that miR-199a-3p has a negative effect on both the growth and drug resistance of OS cell-derived tumor xenografts in nude mice. The gene discussed is AK4; the disease is neoplasm.