In order to better characterize the inverse relationship between CDK2AP1 and miR-21-5p expression as predicted by the results thus far, we performed a multiplex immunofluorescence (IF) and in situ hybridization (ISH) analysis of tumor tissue microarrays (TMAs) encompassing a retrospective cohort of primary oral squamous cell carcinoma of the tongue from patients that received surgery as the primary form of treatment (Table 1). This evidence concerns the gene CDK2AP1 and oral cavity squamous cell carcinoma.