Skin Cancer in Renal Transplant Patients Proposed Project 2005–2006

Skin cancer is extremely common in renal transplant patients, with age and duration of transplantation being two of the commonest risk factors. A recent study by Fergal Moloney showed that genetic polymorphisms which are relevant in the metabolism of azathioprine contribute to a drop in white cell count in people who are heterozygous for TPMT genes, in other words those who metabolise the drug poorly tend to drop their white cell count more readily than those who metabolise the drug well. Renal transplant patients in whom this happens usually have the dose of azathioprine adjusted or stopped. This is usually happens early in the post transplant period. Only about 7% of RTR are heterozygotes for the polymorphism. The remaining 93% metabolise the drug well. There was a trend for patients who were heterozygotes for TPMT who remained on azathioprine to develop more skin cancers in addition. The second finding from the study was that certain genes which control skin and hair colour contribute to the risk for skin cancer, independently to the risk conferred from having the genes known to lead to red hair. We also had the opportunity to look for polymorphisms in Cyclooxygenase 1 and 2 genes which are genes expressed in skin cancers. We know that COX-2 is expressed in skin cancers and that the use of drugs which inhibit COX-2 expression prevent or slow down the growth of skin cancers.