To further examine the oncogenic functions of MTR4 in NPC development in vivo, MTR4 KD and control NPC cells were subcutaneously injected into immunodeficient mice to form NPC tumors, indicating that MTR4 is required for NPC tumor growth in vivo (Figs. 1D, 1E and S1C). The gene discussed is MTREX; the disease is neoplasm.