PLOD2 and head and neck squamous cell carcinoma: PSMC1, NAGK, AREG, DDOST, ATP6V1E1, KDELR1, PLOD2, TMED10, ALG5, ARF3, and OST4 were found to be related to a poor prognosis of HNSCC (P = 0.004, <0.001, 0.027, 0.035, 0.030, and 0.009, respectively) (Figure 6).