American Association for Cancer Research, Clinical Cancer Research, 18(22), p. 4735-4745, 2016
DOI: 10.1158/1078-0432.ccr-16-0323
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Abstract Purpose: There is substantial heterogeneity within human papillomavirus (HPV)-associated head and neck cancer (HNC) tumors that predispose them to different outcomes; however, the molecular heterogeneity in this subgroup is poorly characterized due to various historical reasons. Experimental Design: We performed unsupervised gene expression clustering on deeply annotated (transcriptome and genome) HPV+ HNC samples from two cohorts (84 total primary tumors), including 18 HPV− HNC samples, to discover subtypes and characterize the differences between subgroups in terms of their HPV characteristics, pathway activity, whole-genome somatic copy number alterations, and mutation frequencies. Results: We identified two distinct HPV+ subtypes (namely HPV-KRT and HPV-IMU). HPV-KRT is characterized by elevated expression of genes in keratinocyte differentiation and oxidation–reduction process, whereas HPV-IMU has strong immune response and mesenchymal differentiation. The differences in expression are likely connected to the differences in HPV characteristics and genomic changes. HPV-KRT has more genic viral integration, lower E2/E4/E5 expression levels, and higher ratio of spliced to full-length HPV oncogene E6 than HPV-IMU; the subgroups also show differences in copy number alterations and mutations, in particular the loss of chr16q in HPV-IMU and gain of chr3q and PIK3CA mutation in HPV-KRT. Conclusions: Our characterization of two subtypes of HPV+ HNC tumors provides valuable molecular level information that point to two main carcinogenic paths. Together, these results shed light on stratifications of the HPV+ HNCs and will help to guide personalized care for HPV+ HNC patients. Clin Cancer Res; 22(18); 4735–45. ©2016 AACR.