We have also shown that PDT synergizes with irinotecan to reduce metastatic burden and improve survival outcomes in pancreatic tumor mouse models via a two-way mechanism, in which (i) PDT photodamages ABCG2 drug efflux transporters to prevent irinotecan efflux, and (ii) irinotecan alleviates PDT-induced tumor hypoxia [21–23]. Here, ABCG2 is linked to neoplasm.