RESUMO
Recently, microRNAs (miR) were identified to have potential links with oral squamous cell carcinoma (OSCC) and oropharyngeal squamous cell carcinoma (OPSCC) oncogenesis, specifically miR-21. Since HPV is a major risk factor for the development of these diseases, we aimed to search the literature regarding miR-21 expression in both HPV-positive and HPV-negative OSCC/OPSCC. The search was performed in the PubMed (MEDLINE), Scopus, Web of Science, and Cochrane electronic databases. The research question was as follows: Is there a difference in the tissue expression of miR-21 between patients with HPV-positive and those with HPV-negative OSCC/OPSCC? After conducting a meticulous search strategy, four studies were included, and they had a pooled sample size of 621 subjects with OSCC and/or OPSCC. Three studies did not find any significant difference in miR-21 expression between HPV-positive and HPV-negative OSCC/OPSCC. The findings of this systematic review showed that there are no differences in miR-21 expression between HPV-positive and HPV-negative OSCC/OPSCC. Nevertheless, it is worth noting that there are still insufficient studies regarding this important subject, because understanding how HPV influences miR-21 expression and its downstream effects can provide insights into the molecular mechanisms underlying OSCC/OPSCC development and progression.