Next, to better delineate the association in ovarian cancer, we analyzed a retrospective series of high‐grade serous epithelial ovarian carcinomas without or with mutations in BRCA2. Immunohistochemical analyses revealed downregulation of the monocarboxylate transporter MCT4 (which is responsible for lactate extrusion in glycolytic cells; Fig 1D), and overexpression of the OXPHOS complex I respiratory chain NDUFV2 subunit (one of the genes that were increased in the HR‐defective‐associated S3+ signature; Fig 1E) in BRCA2‐mutated tumors relative to wild‐type high‐grade serous cases. This evidence concerns the gene NDUFV2 and ovarian cancer.