Salivary miR-375 a biomarker for oral potentially malignant disorder

Salivary microRNAs (miRNAs) may act as biomarkers for the detection and long-term monitoring of oral potentially malignant disorder (OPMD), a recent study has found.

Through quantitative reverse-transcriptase polymerase chain reaction, the researchers measured the salivary levels of a miRNA type called miR-375. Forty-five (mean age 47.89±13.39 years, 40 men) OPMD patients participated in the study and were compared against 24 healthy controls (mean age 49.19±10.5 years, 25 men).

In OPMD participants, the mean difference in the cycle threshold value of miR-375 relative to a reference gene was 8.97, while in controls this value was 10.17, which was found to be significantly higher (p=0.01). Such a trend was true regardless of pathological condition.

Further dividing the OPMD group into different clinical subsets, the researchers found that miR-375 could help in the monitoring of disease progression. OPMD participants without dysplasia, for example, had significantly higher levels of the miRNA markers than those with dysplasia (p=0.003).

Receiver operating characteristic curve analysis confirmed these findings and revealed that at a cycle threshold change value of –10.3 and –8.9, miR-375 achieved the optimal differentiation between healthy vs OPMD (area 0.671, sensitivity 0.80, specificity 0.68) and dysplasia vs nondysplasia (area 0.771, sensitivity 0.71, specificity 0.83).

During follow-up, five OPMD participants (12.2 percent) progressed to oral squamous cell carcinoma. These patients also showed significantly suppressed miR-375 expression levels relative to those who saw no such progression (change in cycle threshold, –8.3 vs –10.2), indicating that the miRNA marker could be used to monitor for malignant transformation.