The concept of immunologic surveillance as a defense against cancer has been proved valid in experimental and clinical studies. A deficiency of the immune system increases the risk of malignancy, as exemplified by the increased tumor incidence found in patients with immunologic deficiency diseases and in immunosuppressed patients bearing renal transplants. A 32-year-old man developed carcinoma with metastases during oral methotrexate and steroid therapy for psoriasis. Immunosuppressive agents are increasingly being used in the therapy for nonfatal disorders and in the prevention of immune rejection of transplanted organs. The probability of increased risk of cancer and spread of metastases in these patients should be evaluated by prospective studies.
Harris CC. Malignancy During Methotrexate and Steroid Therapy for Psoriasis. Arch Dermatol. 1971;103(5):501-504. doi:10.1001/archderm.1971.04000170035008