PFN1 and head and neck squamous cell carcinoma: At a 12-month follow-up, disease progression (occurrence of lymph node metastases) occurred in 64.7% (11 patients out of 17) of HNSCC patients with a high serum level of PFN1 (more than 0.32 ng/mL) and only in 42.8 % (6 patients out of 14) of the patients with a non-significantly low serum level of PFN1 (less than or equal to 0.32 ng/mL) (P=0.07) (Fig. 3).