HIF1A and neoplasm: It is worth noting that the FL intensity of HIF-1α in the MN-CCPA ( + ) group after three consecutive rounds of laser irradiation (200 mW cm−2, 10 min each time) was 2.1-fold higher than that of the CCPCA ( + ) group (Fig. 6f and Supplementary Fig. 9b), suggesting that local 5-ALA-PDT without an O2 supply would significantly increase HIF-1α expression in tumor tissues, thereby severely limiting the therapeutic effect.