Expression of Aberrant MicroRNAs and p16INK4a Associated with HPV (6, 11, 16, 18, 31, 33, 35, 42, 43, 44, 45, 52, 53, and 56) in Oral Dysplasia and Squamous Cell Carcinoma: A Retrospective Study.

OBJECTIVE: A few studies indicate that human papillomavirus (HPV) induces aberrant expression of microRNAs (miRNAs) and correlate this with p16INK4a in oral dysplasia (OD) and oral squamous cell carcinoma (OSCC). Therefore, this study aimed to evaluate the expression of miRNA-21, miRNA-22, and miRNA-224 by q-PCR and the p16 INK4a by immunohistochemical (IHC) as markers for HPV-positive OSCC and OD in comparison to controls as miRNA expression can be altered by the HPV oncogenes and hence can be used as a biomarker for HPV positive cases.

MATERIAL AND METHODS: Fifty-two specimens were collected from archived paraffin blocks for patients aged between 19 and 88 (31 males and 21 females) from various oral sites. They were examined by IHC using p16 INK4a, by RT-PCR for the detection of HPV (6, 11, 16, 18, 31, 33, 35, 42, 43, 44, 45, 52, 53, 56), and by q-PCR for the expression of miRNA-21, miRNA-22, and miRNA-224 in positive specimens.

RESULTS: Out of the 15 OD, three were positive by both techniques. Meanwhile, 17 out of all OSCC specimens showed intense nuclear and cytoplasmic staining by p16 INK4a, and only 16 were also positive by RT-PCR. However, all control specimens were negative. MiRNA-21, miRNA-22, and miRNA-224 were overexpressed in 3 specimens of OD and 16 of OSCC.

CONCLUSION: MiRNA-21, miRNA-22, and miRNA-224, besides p16 INK4a, could be used as indicators for HPV-associated OD and OSCC as their expression is attributed to the HPV oncoprotein. Further studies using follow-up data should be done to correlate it with miRNA overexpression.