Single-cell transcriptomic characterization primary HNSCC tumors

Despite aggressive multi-modal treatment, advanced head and neck squamous cell carcinoma (HNSCC) patients are at high risk of recurrence. Matched pairs (n=38) of primary/recurrent tumors were subjected to whole exome and RNA sequencing. Mutational landscapes and genomic copy number alterations indicated diverging clonal origins in a subset of cases. Transcriptional subtyping (classical/CL, basal/BA, inflamed-mesenchymal/IMS) in primary and recurrent HNSCC (n=112) revealed more frequent CL and IMS in primary tumors with low recurrence rates and a prevalence of BA in recurrent tumors associated with p-EMT and early recurrence. 44% of matched cases underwent a subtype change from primary to recurrent tumors, preferably from IMS to BA or CL. In recurrences, HYPOXIA, P-EMT and RADIATION RESISTANCE signatures were up- and TUMOR INFLAMMATION down-regulated compared to index tumors. A therapy-induced selection of transcriptional subtypes demonstrates the importance of molecular characterization of recurrences for second-line therapy decisions to enable optimally tailored treatments. three primary HNSCC tumor samples.