First, we compared the expression levels of miR-451a and KDM7A according to different clinicopathological features, including age, gender, smoking history, alcohol history, tumour size, lymph node metastasis, tumour-lymph node-metastasis (TNM) stage, pathological differentiation, efficacy of cetuximab, and recurrence (Table S4 and S5). Here, KDM7A is linked to metastasis.