Donor origin of neuroendocrine carcinoma in 2 transplant patients determined by molecular cytogenetics

Organ transplant recipients have an increased tumor incidence owing to thei r immunocompromised state. The origin of such tumors, whether donor or reci pient, will have a clinical impact on decision-making concerning immunosupp ressive therapy, retransplantation, and for recipients of other organs from the same donors. We report molecular cytogenetic determination of donor or igin in 2 cases of small-cell neuroendocrine carcinoma developing in sex-mi smatched transplant recipients (kidney and liver). Fluorescence in situ hyb ridization (FISH) analysis was performed on liver core needle biopsy materi al from the liver transplant patient and on liver fine needle aspiration cy topreparations from the kidney transplant patient. The results for the live r transplant patient were confirmed with microsatellite allelic analysis an d with comparative genomic hybridization. In both cases, FISH showed the pr esence of only X chromosomes within the tumor cells, indicating the donor o rigin of the neoplasms. FISH is an excellent method to determine neoplastic origin in sex-mismatched transplant patients. HUM PATHOL 31: 1425-1429, Co pyright (C) 2000 by W.B, Saunders Company.