We found that cuSCC is most similar to HNSCC, followed by LUSC, basal (triple-negative) and HER2 breast cancer and ESCA SCC, but not closely related to cervical SCC, which is overwhelmingly human papillomavirus (HPV) -driven (Fig. 8a and Supplementary Data 10). Here, ERBB2 is linked to head and neck squamous cell carcinoma.