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.
Note: Supplementary data for this article are available at Clinical Cancer Research Online (http://clincancerres.aacrjournals.org/).
- Received February 4, 2016.
- Revision received March 24, 2016.
- Accepted March 28, 2016.
- ©2016 American Association for Cancer Research.