Patients who have been scheduled to receive PDT in our noninvasive cutaneous oncology clinics will be given written information prior to their visit, including a copy of the Informed Consent (IC) that describes the purpose of the study. If the patient indicates that he/she is interested, the physician or study nurse will review the IC with the patient on the day of PDT and answer all questions. After the patient signs the IC, the patient will have their blood drawn by a caregiver who has completed PTS Phlebotomy Training.