Finally, we examined whether the bioorthogonal activation of compound 12 could be applied to tune PDT-mediated cancer cell ablation in multiple cell lines of diverse origin, namely MCF-7 (estrogen receptor-positive breast cancer), MDA-MB-231 (triple negative breast cancer) and Ln18 (glioblastoma)56–58. The gene discussed is ESR1; the disease is glioblastoma.