Background: Head and Neck Squamous Cell Carcinomas (HNSCCs) are heterogeneous malignancies that comprise 90% of the head and neck cancers. HNSCCs originate from the mucosal lining epithelium of the upper aerodigestive tract. Cancer stem cells (CSCs) that generate HNSCCs with the CD44, CD133, and ALDH phenotype and are resistant to radiotherapy and chemotherapy. In the current, the quantitative alteration in CD44 and CD133 expression pre- and post-tumor resection and radiotherapy was evaluated in HNSCC patients. Moreover, the alterations in the expression of Bax, Bak, Bcl-2, ALDH, and PTEN genes were measured. Materials and Methods: Flow cytometry was performed to evaluate the alterations in CD44 and CD133 surface markers pre- and posttumor resection and radiotherapy. Quantitative real-time RT-PCR (qRT-PCR) was conducted to investigate the mRNA expression levels of Bax, Bak, Bcl-2, ALDH, and PTEN. Results: The results indicated that the cancer stem cell CD44 surface marker significantly decreased after tumor resection and radiotherapy in HNSCC cases, while the decrease was insignificant for CD133 marker expression. mRNA expression level of Bcl-2 and ALDH was increased, but Bax and Bak gene expressions were reduced significantly Conclusion: The results also indicated that the expression of CD44 significantly decreased after tumor resection and radiotherapy. The upregulation of mRNA level of Bcl-2 and ALDH, and the downregulation of Bax and Bak gene expression were noted in these cases when compared to the healthy control group.
Keywords: Cancer stem cells; Head and neck squamous cell carcinoma; Therapy resistance.
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