In MEDLINE (PubMed), the reviewers used a combination of keywords, including "oral squamous cell carcinoma," "heat shock proteins," and "metastasis." In addition, they used MeSH terms such as "HSP90 heat-shock proteins" and "neoplasm metastasis." The search strategy also included Boolean operators such as "AND," "OR," and "NOT" to narrow down the search results. This evidence concerns the gene HSP90AA1 and oral cavity squamous cell carcinoma.