Similarly, conditioned medium from macrophages stimulated by P.g. LPS promoted invasion of human primary (HN18, HN30 and HN4) and metastatic (HN17, HN31, and HN12) HNSCC cell lines, and inhibited proliferation of HN18, HN30, HN31 and HN4; this effect is linked to increased nitric oxide and decreased TNF-α in macrophages [122]. This evidence concerns the gene TNF and head and neck squamous cell carcinoma.