Proliferation of nontransformed and transformed epithelial cells in SSTNEGFR. Nontransformed oral keratinocytes (NOK), human tonsillar epithelia (HTE), breast (MCF10A) epithelial cells, and human epidermal keratinocytes (HaCat) (A), transformed UM-SCC1, UD-SCC2, TU-138, and UM-SCC47 HNSCC cells (B), and MDA-MB-231 and -468 TNBC (C) cells undergoing logarithmic proliferation are treated with 0, 10, or 30 μM SSTNEGFR for 3 days, followed by quantification of cell number, expressed as a percentage of untreated (control) cells; ∗p ≤ 0.05, ∗∗p ≤ 0.01. HNSCC, head and neck squamous cell carcinoma; TNBC, triple-negative breast cancer.