Chromosome 6p rearrangement. Chromosome 6p12-p21, which contains RUNX2, frequently undergoes complex rearrangements in osteosarcoma and is one example of a distinct genomic locus that undergoes such alterations in this cancer. In this case, there is gain and amplification of the labeled genes (with wide variation between cells) as shown in the image of interphase fluorescence in situ hybridisation (FISH) for chromosome 6p. The FISH experiment employed probes for FBXO9 (yellow), RUNX2 (orange), PIM1 (green), E2F3 (red), and the centromere of chromosome 6 (light blue). The RUNX2 immunohistochemistry (IHC) image was obtained after staining for RUNX2 protein. High levels of the protein were nearly ubiquitous in the nuclei of cells and were associated with genetic amplification of RUNX2. The FISH and IHC images were obtained via experiments performed on serial formalin-fixed paraffin-embedded sections of one osteoblastic (conventional) osteosarcoma tissue specimen. MSC, mesenchymal stem cell.
