Salivary microRNAs for oral cancer and oral potentially malignant disorder triage: a scoping review and evidence map

Abstract

Background Salivary microRNAs (miRNAs) have been investigated for oral cancer detection, but comparison with healthy volunteers does not establish performance among patients with oral mucosal lesions. This review maps evidence relevant to discrimination between oral squamous cell carcinoma or oral cancer (OSCC/OC) and oral potentially malignant disorders (OPMDs). Methods The evidence was organized as a scoping review with study-specific diagnostic descriptions. Clinical comparators, assay methods, thresholds, participant overlap and data provenance were charted. No estimates were pooled. Searches were executed on 8 September 2026 in PubMed ( n = 487), Web of Science Core Collection ( n = 362), Scopus ( n = 318) and the Cochrane Central Register of Controlled Trials ( n = 34), with 28 additional records identified through citation chasing and reference-list checking, for a total of 1,229 records. After removal of 412 duplicates and 15 records before screening, 802 titles and abstracts were screened; 54 full-text reports were sought, of which 3 could not be retrieved and 51 were assessed. Sixteen sources were included in the evidence map, comprising 13 primary studies and 3 contextual systematic reviews. Results Three diagnostic reports contained five assay-level results for cancer vs. OPMD or oral lichen planus. A four-miRNA panel was reported to have 90% sensitivity and 82.7% specificity in 50 OC and 52 OPMD participants. Two individual miRNAs evaluated in the same 30 OSCC and 30 OPMD participants each had reported sensitivity of 70% and specificity of 60%. An additional oral lichen planus comparison had uncertain ROC analysis denominators and was retained without reconstructed counts. Repeated assays within a cohort were not considered independent studies. Small selected samples, data-derived thresholds, inconsistent reporting and limited independent validation restricted interpretation. Conclusions Salivary miRNAs have shown study-specific discrimination between cancer and selected OPMD groups. Evidence does not establish a transportable accuracy estimate or clinical benefit for lesion triage. Prospective evaluation in consecutive lesion cohorts is needed before these assays can inform biopsy, referral or surveillance decisions.