[Hypervariable regions (HVR) as genetic markers in tumor diagnosis. Methodological principles and their use in...

Variable number tandem repeats (VNTR) are highly polymorphic DNA sequences which can be used as genetic markers in different fields of medicine. In this report, we describe the methodology of VNTR in diagnostic molecular pathology, using a rapid, DNA-based approach involving polymerase chain reaction (PCR) amplification and electrophoresis of highly polymorphic DNA satellite sequences. As concrete examples of the application of this approach, we present two case reports: 1. A B-cell lymphoma of the porta hepatis developed in a 54-year-old man 4.5 months after orthotopic liver transplantation for liver failure due to chronic hepatitis C infection. Using DNA polymorphisms as genetic markers, we showed that the tumor was of donor origin. This finding may be important for the patient's subsequent management. 2. An immature teratoma of the left ovary was found during delivery by cesarean section in a 27-year-old woman. The female newborn survived for 9 weeks and then died from central dysregulation because of an intracranial immature teratoma. Because the synchronous tumors were of similar histology, clonal origin in maternal tissues and metastatic spread were initially suspected. Analysis of highly polymorphic DNA markers clearly indicated that the teratoma carried by the child was of independent genetic origin from the mother's tumor.