Therefore, we investigated the expression of CXCR4 in normal chondrocytes, normal cartilage, chondrosarcoma tissue, and chondrosarcoma cells (CS) and hypothesized that CXCR4 is overexpressed in chondrosarcoma, is upregulated by hypoxia and specifically by HIF-1, and increases the invasive phenotype by increasing expression of MMP1. This evidence concerns the gene HIF1A and chondrosarcoma.