Cancer stem cells and field cancerization of head and neck cancer - An update

Oral cancer results due to multiple genetic alterations that transform the normal cells in the oral cavity into neoplastic cells. These genetic changes in a particular tumor field lead to a rapid expansion of preneoplastic daughter cells producing malignant phenotype but the malignancy results due to such genetic changes occurr over several years. The morphological changes in these transformed cells help in the diagnosis of malignancy. Thus, the early changes at the gene level are present in the population of daughter cells in the organ, which explains the concept of field cancerization. Cancer stem cells (CSCs) represent a group of cells that have the capacity of self-renewal and have the potential to differentiate into other types of tumor cells. This review explains the cellular and genetic basis of field cancerization and the role of cancer stem cells in field cancerization.