Tracking tumor evolution one-cell-at-a-time.

Accumulating evidence suggests that intra-tumor heterogeneity (ITH) within tumor sub-populations is a major contributor to therapy resistance, with genomically distinct clonal populations exhibiting different therapeutic vulnerabilities. Here we employed single-cell transcriptomics in patient-derived primary cells to understand the impact of phenotypic intra-tumor heterogeneity on drug-induced tumor evolution in oral squamous cell carcinoma.