Immunotherapy in Patients with Recurrent and Metastatic Squamous Cell Carcinoma of the Head and Neck.

BACKGROUND: Head and neck squamous cell carcinoma (HNSCC) is the most common malignant cancer occurring in the head and neck area, approximately 90% of the cases. Even in the cases of primary radical treatment (surgical, concomitant chemoradiotherapy or radiotherapy alone), subsequent local recurrence or distant metastases are often observed. In patients with recurrent disease who are unable to receive radical treatment, the results of palliative chemotherapy are not satisfactory. In this review, we summarized the standard treatment options, current development of new drugs and future perspectives in the treatment of patients with recurrent locally advanced and/or metastatic HNSCC. METHODS: PubMed databases with words 'head and neck cancer treatment', 'immunotherapy in head and neck cancer treatment' were searched and yielded 186512 and 2249 papers respectively. We selected the most cited articles and reports presenting new immunotherapy agents and drug combinations in HNSCC. RESULTS: Recently, two new agents been approved in the treatment of recurrent locally advanced and/or metastatic HNSCC. These are immune-checkpoint inhibitors targeting PD1 (nivolumab and pembrolizumab) which are the most active drugs in the second line treatment of advanced HNSCC. Still, the first line 'golden standard' is the chemotherapy regimen (cisplatin, 5-fluorouracyl) combined with cetuximab. Many phase 3 studies are currently ongoing, evaluating the efficacy of combinational treatment-anti-CTLA4 with anti-PD1 or anti-PDL1. Very encouraging results have been shown in early phase studies evaluating the combination of immunecheckpoint inhibitors with tumor microenvironment immunosuppressive inhibitors. CONCLUSION: Despite the huge progress in the systemic treatment of patients with recurrent locally advanced and/or metastatic HNSCC, the disease at this stage remains incurable. Undoubtedly, further research in the field of biomarkers for effective immunotherapy is needed in order to select a group of patients whose will benefit from this therapy, as the treatment is still ineffective in most patients.

Tumor microenvironment - Unknown niche with powerful therapeutic potential.

Head and neck squamous cell carcinomas (HNSCC) are in a group of cancers that are the most resistant to treatment. The survival rate of HNSCC patients has been still very low since last 20 years. The existence of relationship between oncogenic and surrounding cells is probably the reason for a poor response to treatment. Fibroblasts are an important element of tumor stroma which increases tumor cells ability to proliferate. Another highly resistance, tumorigenic and metastatic cell population in tumor microenvironment are cancer initiating cells (CICs). The population of cancer initiating cells can be found regardless of differentiation status of cancer and they seem to be crucial for HNSCC development. In this review, we describe the current state of knowledge about HNSCC biological and physiological tumor microenvironment.

Biological role of long non-coding RNA in head and neck cancers.

Head and neck squamous cell carcinoma (HNSCC) are one of the worst prognosis cancers with high mortality of patients. The treatment strategy is primarily based on surgery and radiotherapy but chemotherapy is also used. Every year the knowledge concerning HNSCC biology is updated with new elements such as the recent discovered molecules - long non-coding RNAs. Long non-coding RNAs are involved in regulatory processes in the cells. It has been revealed that the expression levels of lncRNAs are disturbed in tumor cells what results in the acquisition of their specific phenotype. lncRNAs influence cell growth, cell cycle, cell phenotype, migration and invasion ability as well as apoptosis. Development of the lncRNA panel characteristic for HNSCC and validation of specific lncRNA functions are yet to be elucidated. In this work, we collected available data concerning lncRNAs in HNSCC and characterized their biological role. We believe that the tumor examination, in the context of lncRNA expression, may lead to understanding complex biology of the cancer and improve therapeutic methods in the future.

Unpredictable changes of selected miRNA in expression profile of HNSCC.

BACKGROUND: The necessity of prediction and treatment outcome improvement of HNSCC needs to find new biomarkers. miRNAs seem to be good candidate for that. OBJECTIVE: Analysis of selected 5 miRNAs (let-7d, miR-18a, miR-21, miR-205 and miR-375) as potential biomarkers that allows to distinguish tumor and healthy tissue taken from HNSCC patients. METHODS: Tumor and normal epithelial tissues were obtained from 75 HNSCC patients to analyze selected miRNAs. RESULTS: Analysis indicated significant increase of miR-21 and miR-205 in tumor when compared with healthy tissue (p= 0.0069 and p= 0.0029, respectively). There was a significant correlation between let-7d and miR-18a. let-7d was down-regulated in 34.67% cases, miR-18a in 29.33%, miR-21 in 20%, miR-205 in 30.67% and miR-375 in 52% cases. At the same time over-expression of let-7d was detected in 18.67% cases, miR-18a in 22.67%, miR-21 in 48%, miR-205 in 41.33% and miR-375 in 52% cases. There was no correlation between miRNA expression and clinical data and the course of illness. CONCLUSION: Our study indicated that miR-21 and miR-205 can be used to analyze the clarity of surgical margins and that concomitant changes in the expression of let-7 and miR-18a in tumor tissues might represent important future markers indicating the biology of HNSCC. These observations will help with developing personalization for HNSCC patients' treatment.

The mystery of let-7d - a small RNA with great power.

miRNAs belong to a class of small non-coding RNAs which can modulate gene expression. Disturbances in their expression and function may cause cancer formation, progression and cell response to various types of stress. The let-7 family is one of the most studied groups of miRNAs. The family contains 13 members with similar sequences and a wide spectrum of target genes. In this paper, we mostly focus on one member of the family - let-7d. This miRNA is dysregulated in many types of cancers. It can be over- or down-expressed, and it acts as a tumor suppressor or oncogene. It regulates various genes such as LIN28, C-MYC, K-RAS, HMGA2 and IMP-1. Moreover, let-7d has a significant impact on epithelial-to-mesenchymal transition (EMT) and formation of cancer initiating cells which are resistant to irradiation and chemical exposure and responsible for cancer metastasis. Let-7d can serve as a prognostic and predictive marker for personalization of the treatment. Let-7d is a small RNA with great power, but in different cell genetic backgrounds it acts in different ways, which makes this molecule still mysterious.