Gene expression analysis with cDNA microarrays showed that the expression of HIF-1α was three-fold higher in primary tumors of breast cancer patients with bone micrometastases than in those without the micrometastases, which was associated with the down-regulation of genes responsible for HIF-1α degradation, such as VHL and cullin-2 [66]. The gene discussed is HIF1A; the disease is breast carcinoma.