Independent origin of uterine leiomyomas with karyotypically identical alterations.

Cytogenetic investigation of multiple uterine leiomyomas from the same patient revealed karyotypes containing cytogenetically indistinguishable del(7)(q21.2q31.2) in two of the tumors. Since this finding seemed to contradict the conclusion from previous glucose-6-phosphate dehydrogenase studies of multiple uterine leiomyomas in which an independent origin of these tumors was found, we assessed clonal tumor origin by DNA-recombinant X-chromosome inactivation analysis. The two leiomyomas with del(7)(q21.2q31.2) had different inactivated X-chromosomes. This proves that they originated independently and indicates that their cytogenetic similarity was coincidental.