THE FACTOR-V LEIDEN MUTATION IN CHILDREN WITH CANCER AND THROMBOSIS

Thromboembolic phenomena, frequently observed in children with cancer who are undergoing chemotherapy, can cause significant morbidity and, less frequently, mortality. Many contributory factors have been identi fied. Whether the recently identified and most common coagulation defe ct predisposing to thrombosis, factor V Leiden, is associated with thr ombosis in this setting, has not been explored. The current study was undertaken to determine the prevalence of the factor V Leiden mutation in children with cancer who developed thromboembolic phenomena as com pared to those with cancer who did not. Genomic DNA was amplified usin g the polymerase chain reaction (PCR), followed by digestion of the am plification product with the restriction enzyme MnlI. The digested PCR products were then size-fractionated to classify samples as heterozyg ous, homozygous or normal for the factor V Leiden mutation. 67 childre n with cancer were evaluated for the factor V Leiden mutation. One of 32 children with cancer and thrombosis, and none of 35 who had not exp erienced thrombotic problems, was found heterozygous for this mutation . We conclude that the factor V Leiden mutation does not play a signif icant role in the overall incidence of thromboses that occur in childr en with cancer.