While aminoacyl-tRNA synthetase-interacting multifunctional protein 2 (AIMP2) is a tumor suppressor, its exon 2-depleted splice variant (AIMP2-DX2 or shortly DX2) is highly expressed in human lung cancer, and the ratio of DX2 to AIMP2 increases according to the progression of lung cancer. The gene discussed is AIMP2; the disease is neoplasm.