Genome-wide miRNA profiling reinforces the importance of miR-9 in human papillomavirus associated oral and oropharyngeal head and neck cancer.

Head and neck cancer is the sixth most common malignancy worldwide, predominantly developing from squamous cell epithelia (HNSCC). The main HNSCC risk factors are tobacco, excessive alcohol use, and the presence of human papillomavirus (HPV). HPV positive (+) cancers are etiologically different from other HNSCC and often show better prognosis. The current knowledge regarding HNSCC miRNA profiles is still incomplete especially in the context of HPV+ cancer. Thus, we analyzed 61 freshly collected primary oral (OSCC) and oropharyngeal (OPSCC) SCC samples. HPV DNA and RNA was found in 21% cases. The Illumina whole-genome small-RNA profiling by next-generation sequencing was done on 22 samples and revealed 7 specific miRNAs to HPV+ OSCC, 77 to HPV+ OPSCC, and additional 3 shared with both; 51 miRNAs were specific to HPV- OPSCC, 62 to HPV- OSCC, and 31 shared with both. The results for 9 miRNAs (miR-9, -21, -29a, -100, -106b, -143 and -145) were assessed by reverse transcription-quantitative polymerase chain reaction on the whole study population. The data was additionally confirmed by reanalyzing publicly available miRNA sequencing Cancer Genome Atlas consortium (TCGA) HNSCC data. Cell signaling pathway analysis revealed differences between HPV+ and HPV- HNSCC. Our findings compared with literature data revealed extensive heterogeneity of miRNA deregulation with only several miRNAs consistently affected, and miR-9 being the most likely HPV related miRNA.