Increased expression of mitochondrial transcription factor A and nuclear respiratory factor‑1 predicts a poor clinical outcome of breast cancer

Nuclear respiratory factor-1 (Nrf1) and mitochondrial transcription factor A (TFAM) are involved in the regulation of a variety of mitochondrial functional genes, which are associated with decreased sensitivity of tumor cells to chemotherapy. However, the expression status of Nrf1 and TFAM, as well as their clinical significance in breast cancer, is unknown. In the present study, tumor tissues and corresponding adjacent normal tissues were collected from 336 patients with breast cancer, and Nrf1 and TFAM expression was analyzed by immunohistochemistry using a tissue microarray. Expression of Nrf1 and TFAM was significantly increased in breast cancer tissue compared with adjacent normal tissues. In addition, patients positive for Nrf1 or TFAM had a poorer clinical prognosis than patients who were negative, and those positive for Nrf1 and TFAM had the shortest survival time. These results suggest that Nrf1 and TFAM are potential biomarkers for the determination of individualized therapy and the prognosis of breast cancer, and molecular targeting of Nrf1 and TFAM is a promising strategy for the sensitization of breast cancer cells to chemotherapeutics.