Cancer Stem Cells in Oropharyngeal Cancer

SIMPLE SUMMARY: Although there has been improvement in our understanding about cancer stem cells recently, we still don’t know much about cancer stem cells of oropharyngeal cancer. Lack of knowledge solely on oropharyngeal cancer together with the information of human papilloma virus status, which is a specific factor of prognosis in oropharyngeal cancer, hardens to elucidate the distinction of the underlying mechanisms of cancer stem cell behavior. To proceed to an effective and durable therapy in oropharyngeal cancer it is necessary to reveal cancer stem cell function and related factors like its plasticity, niche, and pathways. Therefore in this review we aimed to contribute to this emerging area by focusing on the current literature and future prospects. ABSTRACT: Oropharyngeal cancer (OPC), which is a common type of head and neck squamous cell carcinoma (HNSCC), is associated with tobacco and alcohol use, and human papillomavirus (HPV) infection. Underlying mechanisms and as a result prognosis of the HPV-positive and HPV-negative OPC patients are different. Like stem cells, the ability of self-renewal and differentiate, cancer stem cells (CSCs) have roles in tumor invasion, metastasis, drug resistance, and recurrence after therapy. Research revealed their roles to some extent in all of these processes but there are still many unresolved points to connect to CSC-targeted therapy. In this review, we will focus on what we currently know about CSCs of OPC and limitations of our current knowledge. We will present perspectives that will broaden our understanding and recent literature which may connect to therapy.