Forward selected, proportional Cox regression of survival modifying parameters (T, N, R, G, tumor localization, MMP2/9, TIMP1/2, CXCR4, and CXCL12) identified CXCR4 being the only survival-modifying parameter in HNSCC (Table 2). The gene discussed is CXCL12; the disease is head and neck squamous cell carcinoma.