Reversion Mutation after Neoadjuvant Dose-Dense EC and Dose-Dense Paclitaxel in Triple-Negative Breast Cancer: A Case Report and Literature Review.
[INTRODUCTION] reversion mutations are known mechanisms of acquired resistance to poly (ADP-ribose) polymerase inhibitors (PARPis) and platinum agents.
APA
Hikino H, Otani A, Makino Y (2026). Reversion Mutation after Neoadjuvant Dose-Dense EC and Dose-Dense Paclitaxel in Triple-Negative Breast Cancer: A Case Report and Literature Review.. Surgical case reports, 12(1). https://doi.org/10.70352/scrj.cr.25-0632
MLA
Hikino H, et al.. " Reversion Mutation after Neoadjuvant Dose-Dense EC and Dose-Dense Paclitaxel in Triple-Negative Breast Cancer: A Case Report and Literature Review.." Surgical case reports, vol. 12, no. 1, 2026.
PMID
41868534
Abstract
[INTRODUCTION] reversion mutations are known mechanisms of acquired resistance to poly (ADP-ribose) polymerase inhibitors (PARPis) and platinum agents. However, their clinical emergence without such therapies is rarely reported.
[CASE PRESENTATION] We describe a 44-year-old woman with early-stage triple-negative breast cancer carrying a germline mutation who developed a reversion mutation after neoadjuvant dose-dense epirubicin and cyclophosphamide (EC) followed by dose-dense paclitaxel, without prior PARPi or platinum exposure. She underwent modified radical mastectomy and achieved a good pathological response; however, she developed early systemic recurrence, including leptomeningeal metastasis, 7 months postoperatively. Comprehensive genomic profiling of the residual breast tumor revealed a reversion mutation (allele frequency: 6.7%) that restored the open reading frame. We speculate that the genomic instability in the tumor may have induced a spontaneous reversion mutation early in the disease course.
[CONCLUSIONS] This case suggests that a reversion mutation can arise early, even before PARPi or platinum exposure. Serial monitoring of status may help predict therapeutic resistance in patients with germline -mutated breast cancer.
[CASE PRESENTATION] We describe a 44-year-old woman with early-stage triple-negative breast cancer carrying a germline mutation who developed a reversion mutation after neoadjuvant dose-dense epirubicin and cyclophosphamide (EC) followed by dose-dense paclitaxel, without prior PARPi or platinum exposure. She underwent modified radical mastectomy and achieved a good pathological response; however, she developed early systemic recurrence, including leptomeningeal metastasis, 7 months postoperatively. Comprehensive genomic profiling of the residual breast tumor revealed a reversion mutation (allele frequency: 6.7%) that restored the open reading frame. We speculate that the genomic instability in the tumor may have induced a spontaneous reversion mutation early in the disease course.
[CONCLUSIONS] This case suggests that a reversion mutation can arise early, even before PARPi or platinum exposure. Serial monitoring of status may help predict therapeutic resistance in patients with germline -mutated breast cancer.