Oral cancer is a common malignancy with high incidence rate [16]. Early detection and timely treatments are pivotal for clinical outcomes of the patients. However, until now the pathology of oral cancer can not be completely explained. Diagnosis and prognosis evaluation remain a great challenge for oral cancer in clinic. Since the functional roles of miRNA in various biological processes, great progression has been made in understanding the etiology of cancer [17]. A growing body of evidences have demonstrated that miRNAs may be the reliable bio-markers for the detection of human cancers because they can present in body fluids in a stable form that could be easily detected [18].
MiR-101 represents a common member of miRNA family, which had been shown to be decreased and play an anti-tumor role in various cancers [19, 20]. Accumulating researches had reported that the abnormal expression of miR-101 was involved in cell proliferation, colony formation, migration and apoptosis through targeting some genes [21, 22]. Given its significant functions in controlling the biological behaviors of tumor cells, miR-101 was considered as a promising candidate bio-marker for therapy and prognosis of some cancers [23, 24]. For examples, the study of Li et al. reported that the expression of miR-101 was decreased in laryngeal squamous cell carcinoma tissues, and showed negative association with high tumor grade, lymph node metastasis as well as advanced clinical stage [25]. Zhang et al. mentioned that the expression of miR-101 was decreased in bladder transitional cell carcinoma tissues and closely correlated with tumor grade, clinical stage and lymph node metastasis of the patients. MiR-101 might be a potential biomarker for prognosis evaluation in bladder cancer [26]. Nevertheless, the diagnostic value of miR-101 in oral cancer patients remained poorly understood.
In the present study, we investigated the expression profile of miR-101 in oral cancer, as well as its diagnostic performance in this disease. We found that the relative mRNA level of miR-101 in serum samples of oral cancer patients was significantly down-regulated compared to that in healthy controls. Chi-square test results showed that patients with reduced miR-101 expression were more likely to have poor histological grade, advanced TNM stage and positive lymph node metastasis. All the data revealed that miR-101 was a tumor suppressor gene in oral cancer, and its down-regulation predicted aggressive tumor progression for oral cancer. These results were in accordance with the previous studies [25, 26]. However, Bao et al. reported that low miR-101 expression was obviously associated with tumor size of gallbladder carcinoma patients, which was different from our result [27]. The divergences might be caused by the different types of malignancy, relatively small sample size as well as the different detection specimens.
Early detection is an effective approach to improve the clinical outcomes of oral cancer patients. In the current study, we estimated whether miR-101 could be applied for the diagnosis of oral cancer. ROC curve analysis demonstrated that serum miR-101 could be an effective bio-marker for distinguishing oral cancer patients from healthy individuals with satisfied AUC, sensitivity and specificity. Serum miR-101 might be a non-invasive biomarker for patients with oral cancer. In addition to oral cancer, the diagnostic significance of serum miR-101 was also confirmed in other types of tumor. Zhuang et al. reported that serum miR-101 showed significantly different between hepatocellular carcinoma patients and healthy controls, which could act as a promising bio-marker for the diagnosis of the disease [28]. However, the precise molecular mechanism of miR-101 in the progression of oral cancer is still poorly known. Further studies will be required.