Published online Jul 26, 2020. doi: 10.4252/wjsc.v12.i7.562
Peer-review started: February 26, 2020
First decision: April 25, 2020
Revised: May 17, 2020
Accepted: May 21, 2020
Article in press: May 21, 2020
Published online: July 26, 2020
Core tip: Photodynamic therapy (PDT) is an effective and promising cancer treatment. PDT directly produces reactive oxygen species (ROS) through photochemical reactions. In this article, we review the production process of oxygen-dependent exogenous ROS and the possible endogenous ROS generation process after PDT-mediated subcellular organelle stress. The intracellular metabolism of several ROS produced by PDT is analyzed. Given the extremely short half-life and limited diffusion distance of ROS, we explain from the subcellular localization of photosensitizers how PDT affects the characteristics of cancer stem cells through changes in mitochondrial permeability, activation of unfolded protein responses, autophagy and so on.