Photodynamic therapy corrects abnormal cancer-associated gene expression observed in actinic keratosis lesions and induces a remodeling effect in photodamaged skin

Actinic keratoses (AK) are lesions formed from proliferations of transformed neoplastic keratinocytes in the epidermis, resulting from cumulative ultraviolet radiation (UVR) from sun exposure [1,2]. Lesions are found on sites of sun-exposed skin such as the face, balding scalp, chest, forearms and back of the hand. AKs may present on a patient as visible lesions, of which 5-10% have the potential to transform into squamous cell carcinoma (SCC) [3,4]. In Organ Transplant Recipients (OTR) as a consequence of long-term immunosuppressive therapy, the risk of developing cutaneous SCC is much higher, with an almost 250-fold increase compared with immunocompetent individuals [5,6].