TGFB1 and head and neck squamous cell carcinoma: A223, a cell line derived from these tumors, also exhibited elevated TGFβ levels in vitro compared to untransformed mouse skin keratinocytes (MNK) and the murine HNSCC cell lines LY233, and A1419, a SCC cell line we derived from 4NQO-induced SCC (P < 0.0001 for all, n = 6) (Fig. 1a).