Researchers at Harvard Medical School implanted human kidney cancer cells into mice and then gave the rodents cyclosporine, an immunosuppressant drug often used after transplants. Mice that received the drug grew tumors at a faster rate than mice left untreated.
The study found that cyclosporine boosts the production of vascular endothelial growth factor (VEGF), which indicated the growth of new cancer-feeding blood vessels.
The tumors themselves may have already existed before the transplant procedure or they may be a return of an old cancer, the researchers said, adding that a virus introduced from the donor organ can also trigger the cancer.
An estimated 15 to 20 percent of transplant patients develop cancer within 10 years or surgery, the study's lead investigator Soumitro Pal, wrote in the July 15 issue of Cancer Research.
