Gene expression analysis of TIL rich HPV driven head and neck tumours reveals a distinct B-cell signature when compared to HPV independent tumours.

Purpose: Human papilloma virus (HPV) associated head and neck squamous cell carcinoma (HNSCC) has a better prognosis than HPV(-) negative cancer. This may be due, in part, to the higher number of tumour infiltrating lymphocytes (TIL) in HPV(+) tumours. We used RNAseq to evaluate whether these differences in clinical behaviour could be explained simply by a numerical difference in TILs or whether there was a fundamental difference between TILs in these two settings. Patients and methods: Twenty-three consecutive HNSCC cases with high and moderate TIL density were subjected to RNAseq analysis. Differentially expressed genes (DEG) between 10 HPV(+) and 13 HPV(-) tumours were identified with EdgeR. Immune subset analysis was performed using, FAIME (Functional Analysis of Individual Microarray Expression) and Immune gene transcript count analysis. Results: 1634 genes were differentially expressed. There was a dominant immune signature in HPV(+) tumours. After normalizing expression profiles for numerical differences in T cells and B cells, 437 significantly DEGs still remained. A B-cell associated signature emerged, which segregated HPV(+) from HPV(-) cancers and included CD200, STAG3, GGA2, SPIB and ADAM28. Differential expression of these genes was confirmed by real-time quantitative PCR and immunohistochemistry. Conclusion: In our dataset, the difference associated with T-cells between patients with HPV(+) and (-) HNSCC was predominantly numerical. However, when TIL numbers are corrected, a distinct differential B-cell signature was revealed. Overall design: mRNA profiles of 10 HPV driven (HPV+) and 13 HPV independant (HPV-) head and neck squamous cell carcinoma (HNSCC) tumours were generated by RNA-Seq, using Illumina HiSeq 2000.

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Fleming JC, Woo J, Moutasim K, Mellone M, Frampton SJ, Mead A, Ahmed W, Wood O, Robinson H, Ward M, Woelk CH, Ottensmeier CH, King E, Kim D, Blaydes JP, Thomas GJ