P4HA1 and head and neck squamous cell carcinoma: Two of the genes composing the SCCHN TMI, MASP1 and EGFL6 are associated with good prognosis (HR < 1) while the other four: SFRP5, SPP1, MMP8 and P4HA1 are associated with poor outcomes (HR > 1), as shown in Table S1.