Conceptualizing Cancer Stem Cells in Head and Neck Squamous Cell Carcinoma

There is increasing evidence that the growth and spread of cancers is driven by a small subpopulation
of cancer stem cells (CSCs) - the only cells that are capable of long-term self-renewal, proliferation
and generation of the phenotypically diverse tumor cell population. CSCs have been identified and
isolated in a variety of human cancers including head and neck squamous cell carcinoma (HNSCC).
Studies of many cancer types including HNSCC have identified CSCs using specific markers, but it is
still unclear as to where in the stem cell hierarchy these markers fall. This is compounded further by
the presence of multiple CSC subtypes within HNSCC, making investigation reliant on the use of
multiple markers. The concept of cancer stem cells may have profound implications for our
understanding of tumor biology and for the design of novel treatments targeted toward these cells. In
this chapter we explore the current knowledge in CSC markers. We further attempt to conceptualize
the role of CSCs in HNSCC – its implication in tumorigenesis and the possible additional approach in
current treatment strategies.