In the assay of either cultured cell proliferation or colony formation, the knockdown of C1orf112 with two independent sh-RNAs in the osteosarcoma cells (MNNG-HOS) led to strong inhibition on cell proliferation even in the presence of high medium concentration of methionine (200 μM) (Fig. 7A, B) and overexpression of C1orf112 neutralized the inhibitory effect of methionine-restriction on osteosarcoma cell proliferation (Fig. 7C). The gene discussed is FIRRM; the disease is osteosarcoma.