Prognostic Value of CD4+ Regulatory T‐cell Subpopulation in Oropharyngeal Squamous Cell Carcinoma

Abstract

The oropharyngeal (Op) subsite is the third most common in newly-diagnosed HNSCC (1). While some risk factors and/or etiologies for OpSCC are well-established (such as chronic alcohol intake, chronic tobacco usage, human papilloma virus), there are other contributing factors that are less well understood and that warrant further study (2-4). One of these is the role of tumor immunology in SCC. A fundamental concept in tumor immunology is that of immune homeostasis. This supposition hypothesizes that through activities and interactions of various effector and regulatory cell populations, the host immune system can produce a specific response to a desired level of intensity, duration, and specificity to foreign and altered-self antigens (i.e. neoplasia). A recently characterized group of lymphocytes that has incurred much interest and investigation for its role in immune homeostasis is collectively called regulatory T-cells (RTC). RTC are composed of multiple distinct T cell subpopulations and have been hypothesized to play pivotal roles in controlling immune homeostasis and tumor surveillance (5-6). This study was conducted to quantify and characterize three CD4+ RTC subpopulations (Treg, Tr1, TH3) in newlydiagnosed patients with OpSCC compared to age-similar, cancer-free smokers. An additional focus of this study was to monitor CD4+ RTC levels over time and in response to prescribed treatment and changes in cigarette smoking status. We hypothesized that CD4+ RTC subpopulations in the peripheral blood would change according to smoking and/or clinical cancer status. Furthermore, we sought to correlate RTC subpopulation changes with cancer eradication and overall survival rates to determine whether such changes could have prognostic value for OpSCC patients. Prognostic Value of CD4+ Regulatory T-cell Subpopulation in Oropharyngeal Squamous Cell Carcinoma Jason M Guillot, MD; Karen T Pitman, MD, FACS; William H Replogle, PhD; Gailen D Marshall, MD, PhD, FACP