FLRT3 and head and neck squamous cell carcinoma: In the HPV+ Yellow network, two central genes were shown to be significantly underexpressed and more methylated compared to HPV− HNSCC, GJB6 (gap junction protein beta 6, also known as connexin 30) and FLRT3 (fibronectin leucine rich transmembrane protein 3) (Figs 2 and 4B).