A recent study has revealed elevated expression and phosphor-activation (Tyr105) of PKM2 in HNSCC cell lines from different origins, including laryngopharynx, pharynx-derived metastasis from pleural effusion, soft palate-derived metastasis from a cervical lymph node, alveolar ridge, and HPV(+) and HPV(-) tongues [44]. This evidence concerns the gene PKM and Pleural effusion.