FIRRM and osteosarcoma: Collectively, these data strongly suggest that the expression level of C1orf112, a newly identified molecular signature of cancer cells in the context of methionine deprivation, plays a pivotal role in mediating methionine-deprivation induced osteosarcoma cell growth and metastasis, and in this context, such effects of C1orf112 are tightly coupled with the regulation of mitochondrion oxidative phosphorylation activity.