Despite continued widespread use, the genomic effects of cisplatin-based chemotherapy and implications for subsequent treatment are incompletely characterized. Here, we analyze whole exome sequencing of matched pre- and post-neoadjuvant cisplatin-based chemotherapy primary bladder tumor samples from 30 muscle-invasive bladder cancer patients. We observe no overall increase in tumor mutational burden post-chemotherapy, though a significant proportion of subclonal mutations are unique to the matched pre- or post-treatment tumor, suggesting chemotherapy-induced and/or spatial heterogeneity. We subsequently identify and validate a novel mutational signature in post-treatment tumors consistent with known characteristics of cisplatin damage and repair. We find that post-treatment tumor heterogeneity predicts worse overall survival, and further observe alterations in cell-cycle and immune checkpoint regulation genes in post-treatment tumors. These results provide insight into the clinical and genomic dynamics of tumor evolution with cisplatin-based chemotherapy, suggest mechanisms of clinical resistance, and inform development of clinically relevant biomarkers and trials of combination therapies.
Recommended CitationLiu, David; Abbosh, Philip; Keliher, Daniel; Reardon, Brendan; Miao, Diana; Mouw, Kent; Weiner-Taylor, Amaro; Wankowicz, Stephanie; Han, Garam; Teo, Min Yuen; Cipolla, Catharine; Kim, Jaegil; Iyer, Gopa; Al-Ahmadie, Hikmat; Dulaimi, Essel; Chen, David Y.T.; Alpaugh, R. Katherine; Hoffman-Censits, Jean; Garraway, Levi A.; Getz, Gad; Carter, Scott L.; Bellmunt, Joaquim; Plimack, Elizabeth R.; Rosenberg, Jonathan E.; and Van Allen, Eliezer M., "Mutational patterns in chemotherapy resistant muscle-invasive bladder cancer." (2017). Department of Medical Oncology Faculty Papers. Paper 73.
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