IL17A and cutaneous mastocytosis: CMCD is caused by at least five mutations that ultimately affect the IL-17 pathways; One of these is a mutation in the autosomal dominant gene gain of function of the STAT 1 signaling protein, in which a genetic defect intensifies Th1 immune responses and ultimately reduces the production of IL-17 and IL-22.21 In another study, Domingues-Ferreira et al examined a patient with chronic mucocutaneous candidiasis who had decades of treatment-resistance esophageal candidiasis and eventually developed epidermoid esophageal cancer.