Clonal analysis of human gynecologic cancers by means of the polymerase chain reaction.

Clonality of human gynecologic cancers was analyzed in small DNA samples prepared from cryostat sections, by means of the polymerase chain reaction (PCR). The method used for clonal analysis was based on restriction fragment length polymorphism of the X-chromosome-linked phosphoglycerokinase (PGK) gene and on the differential methylation of the PGK gene due to random inactivation of 1 of 2 X-chromosomes by methylation in females. Among 52 gynecologic cancers tested, 25 were found to be heterozygous for the BstXI polymorphism of the PGK gene. All the 25 gynecologic cancers (4 cervix, 11 endometrium, 7 ovary and 3 fallopian tube) analyzed by the PCR-based method were monoclonal in origin while adjacent normal tissues were polyclonal. When DNA samples were prepared from widely separated sites of tumors and/or metastatic lesions, every sample was found to be monoclonal, and the same allele of the PGK gene was inactivated in each case. These results demonstrate that clonal analysis by PCR offers a good method for studying clonality in small DNA samples prepared from cryostat sections of tumors. This method could be applied to distinguish between benign and malignant gynecologic lesions.