Association of BRCAness with taxane resistance in triple-negative breast cancer: A study of 7 cases

Introduction: Chemotherapy is the only systemic treatment option for triple-negative breast cancer (TNBC) patients, and is often used in combination with anthracycline and taxane. However, it was reported that many TNBCs show BRCA dysfunction, and are sensitive to DNA-damaging agents, but tend to be resistant to mitotic poisons, such as taxanes. Case Series: Triple-negative breast cancer patients who underwent neoadjuvant chemotherapy with anthracycline followed by taxane were analyzed. Clinical responses to taxane were evaluated by the percentage of shrinkage in tumor size after anthracycline treatment. BRCAness was analyzed by mutiplex ligation-dependent probe amplification (MLPA) in core-needle biopsy specimens of 7 patients with progressive disease or stable disease after taxane treatment. BRCAness scores of the 7 patients were between 0.779 and 1.000 (0.939 ± 0.084), and all were categorized as having BRCAness. Conclusion: Patients resistant to taxane were categorized as having BRCAness by MLPA. Mutiplex ligation-dependent probe amplification may hence be a promising method to identify TNBC patients with taxane resistance.