It is possible that RUNX2 overexpression resulting from gain and amplification of chromosome 6p12-p21 is a causative factor in osteosarcoma pathogenesis, because it is consistently overexpressed in patient specimens [12, 128, 131, 132], because of its oncogenic potential, and because of the potential for its tumour suppressor functions to be deregulated. The gene discussed is RUNX2; the disease is neoplasm.