EGFR and squamous cell carcinoma: Evaluation of the photocytotoxicity on EGFR-positive human epidermoid carcinoma A431 cells demonstrated significant enhancement (8.6 and 5.4 times, respectively) of the efficacy of chlorin e6 attached to MNT1 (EC50 = 37.7 nM, CI 23.3–59.4 nM) when compared to either free chlorin e6 (EC50 = 324.7 nM, CI 290.1–362.4 nM) or chlorin e6 attached to control MNT0 lacking an antiKeap1 monobody fragment (EC50 = 204.1 nM, CI 137.8–300.7 nM) (Figure 8).