Basic and Clinical Aspects of photodynamic Therapy -- Mechanisms of Resistance to Photodynamic Therapy -- Tumor Vascular Microenvironment Determines responsiveness to Photodynamic Therapy -- Autophagy Pathways Activated in Response to PDT Contribute to Cell Resistance Against ROS Damage -- Methods to isolate the Resistant Cells to Photodynamic Therapy -- GRP78-Targeting Subtilase Cytotoxin Sensitizes Cancer Cells to Photodynamic Therapy -- Optimization of Photodynamic Therapy Response by Survivin Gene Knockdown in Human Metastatic Breast Cancer -- Cellular Targets and Molecular Responses Associated with Photodynamic Therapy -- The Use of Nanoparticle-Delivered Photosensitizers Can Overcome the Development of Resistance to PDT in Tumors -- Mechanisms of tumor cells resistance to ALA/PDT -- Overcoming the Resistance of Meolanoma to Photodynamic Therapy.