CXCL8 and head and neck squamous cell carcinoma: After HNSCC cells (SCC4, SCC9 and SCC25 cells) were incubated with IL-8 siRNA for 6, 12 and 24 h, the fall in IL-8 reduced cell survival of three types of HNSCC cell below that obtained using control IL-8 siRNA alone (Figure 4A).