A biomarker discovery approach using immunoscreening of a T7 complementary DNA (cDNA) library of breast cancer (BC) proteins with sera from patients with BC containing high titer anti-mitochondrial autoantibodies (AMAs) identified the presence of autoantibodies to Mitochondrial Nuclear Retrograde Regulator 1 (MNRR1; also CHCHD2, AAG10). This evidence concerns the gene CHCHD2 and breast carcinoma.