MiRNA analysis between malignant and benign tissue and circulating exosomes (CE) in patients (pts) with tongue squamous cell carcinoma.

Abstract

6088 Background: The identification of a specific miRNA pattern in HNSCC is challenging given the heterogeneity of this disease and different methodologies used in prior studies. Here we chose to group pts according to primary tumor location and used Nanostring as a larger miRNA platform. Methods: CE-miRNA was isolated from 500ul of plasma collected in Heparin/EDTA tubes. Samples were pretreated with Pacific Hemostasis Thromboplastin D. Supernatant was treated with ExoQuick. Exosomal pellet was resuspended in 1ml of QIAzol Lysis Reagent. Formalin fixed paraffin embedded (FFPE) samples were deparaffinized and digested with proteinase K. miRNA from plasma and FFPE were isolated with miRNeasy Mini Kit. Samples were processed by Nanostring Technology. In this analysis, only tongue cancer pts were selected due to availability of paired tumor and benign tissue miRNA in conjunction with CE from the same pts and others with tongue cancer. Results: 21 HNSCC pts and 32 age-matched controls have enrolled to date. For homogeneity we analyzed only patients with tongue cancer (n=9): 8 males, median age 55.5 years (range 24-64), all had stage IVA tongue cancer (6 base of tongue), 6 HPV/p16 positive. Nine pts received chemoradiation; 4 also had surgery; 8 had clinical and radiological complete response. Of the 800 miRNAs tested 62 were overexpressed and 15 were suppressed in the tumor compared to benign tissue in the same pts. Of those overexpressed and suppressed in tumor tissue, 4 (miR23a-3p; miR150-5p; miR199a-5p; miR203) had a post/pre treatment average ratio (PPTAR) less than 1, while 4 (miR720; miR1253; miR145-5p; miR1283) had PPTAR greater than 1, respectively on CE of pts. miR150-5p was suppressed and miR1283, miR145-5p and miR1253 were overexpressed on CE of control samples compared to pre treatment samples of pts. Conclusions: Of the 800 miRNAs, 8 appear to correlate with treatment response. The average levels of 4 of those miRNA mirror the average levels of tumor tissue miRNA and is in an inverse relationship with benign tissue and control blood samples, suggesting this may be a unique signature for tongue cancer. This observation needs to be validated in larger studies.