ABSTRACT
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.
ABSTRACT
Head and neck cancers are highly prevalent worldwide. Most of these lesions are diagnosed in the advanced stages of the disease. Thus, they do not often have a good long-term prognosis. Like other cancer types, head and neck cancers are managed by surgery, radiotherapy, and chemotherapy. Despite significant advances in the treatment of oral squamous cell carcinoma (OSCC), physicians encounter several challenges in the course of treatment. Various mechanisms mediate the clinical responses of a certain cancer to medications. Thus, efficient treatment planning requires adequate knowledge about the genes involved in drug resistance and the evaluation of the frequency percentage of resistance. Several studies have evaluated the causes and frequency percentages of 5-fluorouracil (5-FU) and cisplatin resistance. In this systematic review, all the relevant articles published until November 30, 2019, were retrieved from the Scopus, Embase, Medline, ISI, Web of Science, and Cochrane databases using certain MeSH and EMTTree keywords. A total of 2164 articles were retrieved of which, 18 were included in the review since they had reported the frequency percentages of drug resistance. Of all, 10 articles had evaluated cisplatin (1317 samples). A meta-analysis of the results revealed a frequency of 33% for cisplatin resistance. Eight studies had evaluated 5-FU (476 samples). A meta-analysis of the results revealed a frequency of 40.2 % for 5-FU resistance. Overcoming cisplatin resistance or 5-FU resistance can significantly enhance recovery in advanced HNSCC. Attempts should be made to eliminate the cause and use multi-drug regimens to increase the success rate of treatment.
