COX4I2 and glioblastoma: We and others have now shown that the isoform expression of specific nuclear-encoded CcO subunits is associated with aggressive malignant behavior and resistance to apoptosis in breast carcinoma (COX7AR), lung adenocarcinoma (COX6B2), and glioblastoma (GBM) (COX4) [9,10,11,12,16,17,18] cells.