It is stated that miR-21 down-regulates programmed cell death 4 (PDCD4) in OSCC.[81] miR-21 up-regulation is correlated with advanced stages of OSCC and lymph node metastasis.[82] Therefore, a positive relationship exists between high expression of miR-21 and worsened prognosis in HNSCC. This evidence concerns the gene PDCD4 and head and neck squamous cell carcinoma.