To determine whether sacral chordoma is monoclonal or polyclonal in origin, a new assay to study the polymorphic human androgen receptor locus (HUMARA) was applied. The ratio of maternal inactive X-chromosone to the paternal inactive X (Lyon hypothesis) was determined via a methylation-specific polymerase chain reaction (PCR) technique. Seven of seven informative samples showed a polyclonal proliferation pattern. This study suggests that chordomas are more comparable to mesenchymal neoplasms than to monoclonal hematopoeitic neoplasms.

The purpose of this study was to determine whether sacral chordoma is monoclonal or polyclonal in origin via a new molecular genetic assay of the x-chromosome.

A polyclonal proliferation pattern was identified in all informative samples studied.

Characterization of the genetic tumorigenesis of this unpredictable neoplasm may lend insight into its biological behavior and offer novel therapeutic intervention.

Utilizing a new assay to study the polymorphic human androgen receptor locus (HUMARA), the ratio of maternal inactive X-chromosome to the paternal inactive X (Lyon hypothesis) is determined via a methylation-specific polymerase chain reaction (PCR) technique to detect X-chromosome polymorphisms. Eight female chordoma patients had their DNA harvested and their x-chromosome inactivation pattern and polymorphisms determined and compared to control. A polyclonal proliferation pattern was identified in seven of seven informative samples. The eighth sample showed a single x chromosome allele in normal and tumor tissue and was thus viewed as uninformative.