HPGD and head and neck squamous cell carcinoma: The inverse correlations for miR-21-GPD1L, miR-21-HLF, miR-21-HPGD and miR-130b-MGLL were statistically significant in OTSCC tissue samples, and the inverse correlations for miR-21-HLF and miR-21-HPGD were also statistically significant in HNSCC cell lines.