Interestingly, even with a relatively small sample size, gene expression profile (Fig 2E) in the HNSCC PDXs mirrored the established distribution of the HNSCC subtypes (21% Atypical, 26.3% Basal, 13.2% Classical and 39.5% Mesenchymal) and importantly, ETS1 expression was preferentially enriched in Mesenchymal subtype (Fig 2F) similar to TCGA datasets. Here, ETS1 is linked to head and neck squamous cell carcinoma.