FIGURE 2

Cytogenetic analysis of intravenous leiomyomatosis. A partial GTG-banded karyotype (A) shows two normal chromosomes 12, one normal chromosome 14, and an abnormal chromosome 14 derived from t(12;14)(q15;q24). Metaphase chromosomes from the intracaval mass were hybridized with biotin-labeled cosmid 142H1 and digoxigenin-labeled cosmid 27E12, which correspond to the 5' and 3' regions of HMGIC (HMGA2), respectively (Panel B), and detected with avidin–fluorescein isothiocyanate (FITC) and rhodamine–anti-digoxigenin conjugates, respectively. The probes hybridized to both copies of chromosome 12 and the der(14) chromosome, indicating that the tumor has three copies of HMGIC (HMGA2) and distal 12q. Consistent co-localization of both cosmids shows that the chromosome 12 breakpoint falls outside of HMGIC (HMGA2). Additional fluorescence in situ hybridization experiments were performed with digoxigenin-labeled cosmid 27E12 (detected with rhodamine–anti-digoxigenin conjugate) and biotin-labeled BAC 475C2 (detected with avidin-FITC conjugate), which corresponds to a chromosome 14 locus within RAD51B (C). Close juxtaposition of these probes shows that the rearrangement in this case of intravenous leiomyomatosis involves the same regions of chromosomes 12 and 14 as those seen in typical uterine leiomyomata.