In one case, humanized monoclonal anti-IL17 treatment of psoriatic lesions in a patient with colon cancer was associated with cancer relapse after initial successful therapy with anti-programmed cell death protein 1 (PD-1) (42), though it is not clear whether this patient would have relapsed without the depletion of IL17A. This evidence concerns the gene PDCD1 and malignant colon neoplasm.