WNT3A and neoplasm: This study highlights several key findings: (1) miR-503 was found to act as a tumor suppressor in HNC; (2) miR-503 plays an important role in HNC progression by inhibiting invasion; (3) miR-503 directly regulates WNT3A and the downstream genes of the Wnt signaling pathway in HNC; and (4) miR-503 regulates the invasive ability of HNC cells through MMP family genes.