Correlation between cancer stem cell marker CD44, proliferation marker Ki-67 and tumor behavior in head and neck squamous cell carcinoma

Abstract

Head and neck cancer accounts for more than 780,000 cases annually worldwide. • The main risk factors include tobacco and alcohol use and HPV virus infection. • Most of patients present with late stage disease with the cure rates reach only 30%. • Despite aggressive treatments with combinations of surgery, radiation and chemotherapy, little progress has been made towards better outcomes. • In recent years, many studies have shown that some types of tumors are characterized by the presence of cells with stem-like characteristics, called cancer stem cells (CSCs). These are considered cells that initiate the tumor and are probably responsible for tumor recurrence. • Cancer stem cells can be identified via surface markers, CD44 is a type I transmembrane glycoprotein expressed in several cell types of mesenchymal and neuroectodermal origin. CD44 functions as a major adhesion molecule and in the cellular internalization of hyaluronic acid. • Numerous studies have highlighted the connection between CD44, hyaluronic acid, and the PI3K–Akt system, whose stimulation leads to phosphorylation of Akt (also known as Summary and Conclusion 133 protein kinase B). p-Akt positively involved in the processes of cell survival and in the development of resistance to chemotherapy. • Also Ki 67 as a proliferation marker was investigated for