EGFR and neoplasm: To address this heterogeneity-driven resistance to targeted therapies, we attempted to recapitulate heterogeneity in vitro, by forming 3D heterocellular models of MIA Paca-2 and SCC-9 cells, with the addition of low-EGFR-expressing T47D or SKOV-3 cells, that represent tumor subpopulations which we have shown to evade EGFR-targeted PDT using Cet-PINs (Figure 8a).