Malignancies in organ transplant recipients.

The development of cancer in organ transplant recipients is well known; depressed immunosurveillance induced by the use of immunosuppressive agents for prevention of rejection is a causative factor. The types of malignancies in renal transplant patients vary geographically and are influenced by the type of immunosuppressant used. In the present study in Japan, malignancies had developed in 2.6% of renal transplant recipients; the observed number/expected number ratio was 2.78. For the primary sites, the relative risk in Japan was quite different from that in Western countries, with a lower frequency of skin cancer, an absence of Kaposi's sarcoma and higher frequencies of renal and thyroid cancer in Japan. Epstein-Barr virus is an oncogenic virus causing lymphoproliferative disorders in immunocompromised hosts. In renal transplant recipients, who usually receive hemodialysis before transplantation, human T lymphotrophic virus (HTLV)-1 is also oncogenic and causes adult T-cell leukemia/lymphoma. The HTLV-1 in donor blood might be transmitted to transplant recipients via transfusion during hemodialysis. The epidemiology and characteristics of representative malignancies in transplant recipients are described, with a review of pertinent literature.