SYCP2 and head and neck squamous cell carcinoma: In HPV-positive premalignant tissue, the SYCP2 (synaptonemal complex protein 2), involved in the organization of chromatin is up-regulated (5), and in HPV-positive HNSCC recurrent mutations have been identified in the tumor suppressor genes PTEN and TRAF3, and in the PIK3CA (phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha) gene, which promotes carcinogenesis (129).