The tumor immune microenvironments of HPV+ and HPV- head and neck cancers.

Human papillomaviruses (HPVs) are the etiological agent of a significant, and increasing, fraction of head and neck squamous cell carcinomas (HNSCC)-a heterogenous group of malignancies in the head and neck region. HPV infection accounts for approximately 25% of all cases, with the remainder typically caused by smoking and excessive alcohol consumption. These distinct etiologies lead to profound clinical and immunological differences between HPV-positive (HPV+ ) and HPV-negative (HPV- ) HNSCC, likely related to the expression of exogenous viral antigens in the HPV+ subtype. Specifically, HPV+ HNSCC patients generally exhibit better treatment response compared to those with HPV- disease, leading to a more favorable prognosis, with lower recurrence rate, and longer overall survival time. Importantly, a plethora of studies have illustrated that the tumor immune microenvironment (TIME) of HPV+ HNSCC has a strikingly distinct immune composition to that of its HPV- counterpart. The HPV+ TIME is characterized as being immunologically "hot," with more immune infiltration, higher levels of T-cell activation, and higher levels of immunoregulation compared to the more immunologically "cold" HPV- TIME. In general, cancers with an immune "hot" TIME exhibit better treatment response and superior clinical outcomes in comparison to their immune "cold" counterparts. Indeed, this phenomenon has also been observed in HPV+ HNSCC patients, highlighting the critical role of the TIME in influencing prognosis, and further validating the use of cancer therapies that capitalize on the mobilization and/or modulation of the TIME. This article is categorized under: Cancer > Molecular and Cellular Physiology Infectious Diseases > Molecular and Cellular Physiology.