Effect of human leukemia cells in testicular tissues grafted into immunodeficient mice

To preserve the fertility of prepubertal boys with childhood cancer, it has been proposed that testicular tissues could be harvested before treatment and then immature germ cells matured by xenografting under the skin of immunodeficient mice. However, malignant cells present in the testicular tissue may disturb spermatogenesis in the xenografts. Here we examined the effect of human leukemia cells on ectopic xenografts in immunodeficient mice.

First, in order to evaluate the tumor forming ability of Human leukemia cells (Jurkat cells), different amounts of these cells were injected into nude mice and analyzed 8 weeks later. Testicular tissues from 5-week-old donor SCID mice injected with Jurkat cells were xenografted under the skin of recipient nude mice. After 8 weeks, xenografts were histologically evaluated and expression of testicular markers in xenografts was assessed.

More than 1 x 10(6) Jurkat cells were necessary to develop a tumor under the skin of nude mice. Eight weeks after xenografting, 5 of 20 xenografts (25%) developed tumors. Spermatogenesis was not detected in any xenografts. Testicular cells were not detected in the tumor by the reverse transcription-polymerase chain reaction technique.

Human leukemia cells infiltrating testicular tissue may disturb spermatogenesis in xenografts. Xenografting cannot be considered a reliable method for the detection of human leukemic cells in testicular tissues before auto-transplantation. Other measures should be developed to preserve the fertility of prepubertal boys with leukemia.