Pavel Smilek

Epidermal growth factor receptor (EGFR) expression and mutations in the EGFR signaling pathway in correlation with anti-EGFR therapy in head and neck squamous cell carcinomas.

UNLABELLED Epidermal growth factor receptor (EGFR) is an important therapeutic target and a poor prognosis factor in head and neck squamous cell carcinoma (HNSCC). The aim of the study was to analyze EGFR expression and KRAS and EGFR mutational status and to correlate it with treatment response to anti-EGFR therapy combined with radiotherapy in 29 patients with advanced head and neck squamous cell carcinomas (HNSCC).EGFR gene expression normalized to GAPDH and EGFR variant type III (EGFRvIII) was detected in tumor tissue using real time reverse transcription -PCR. The mutational status of the EGFR and KRAS genes was investigated by real time PCR with sequence specific primers.Gene expression median values were 3.1x10(8) GAPDH gene copies per µg of RNA, and 8x10(6) EGFR gene copies per µg of RNA. The median EGFR/GADPH ratio reached 0.14. Patients, who achieved complete response after Cetuximab combined with radiotherapy, had significantly higher expression of the EGFR gene in tumors than patients with partial remission or patient without treatment response. An EGFRvIII mutation was found in 20.7 % of patients and no association was found between this mutation and treatment response. 27 patients (93.1 %) had an EGFR gene wild type tumor, and deletion in exon 19 was found in two patients with a poor clinical outcome. Most of the patients (82.8%) had a KRAS wild type tumor; a p.Gly12Cys was found in three patients and a p.Gly12Val mutation in one. Presence of a p.Gly12Val mutation in the KRAS gene was associated with an absence of response to treatment. CONCLUSION Our data suggest that KRAS mutation (p.Gly12Val) and somatic EGFR mutation located in exon 19 may contribute to the limited clinical response to therapy with cetuximab + radiotherapy. Higher EGFR gene expression serves as an independent indicator of good clinical response to EGFR-targeted therapy + radiotherapy.

MicroRNAs Involvement in Radioresistance of Head and Neck Cancer

Resistance to the ionizing radiation is a current problem in the treatment and clinical management of various cancers including head and neck cancer. There are several biological and molecular mechanisms described to be responsible for resistance of the tumors to radiotherapy. Among them, the main mechanisms include alterations in intracellular pathways involved in DNA damage and repair, apoptosis, proliferation, and angiogenesis. It has been found that regulation of these complex processes is often controlled by microRNAs. MicroRNAs are short endogenous RNA molecules that posttranscriptionally modulate gene expression and their deregulated expression has been observed in many tumors including head and neck cancer. Specific expression patterns of microRNAs have also been shown to predict prognosis and therapeutic response in head and neck cancer. Therefore, microRNAs present promising biomarkers and therapeutic targets that might overcome resistance to radiation and improve prognosis of head and neck cancer patients. In this review, we summarize the current knowledge of the functional role of microRNAs in radioresistance of cancer with special focus on head and neck cancer.

Coffee in Cancer Chemoprevention

Coffee consumption is associated with a reduced risk of several diseases including cancer. Its chemopreventive effect has been studied in vitro, in animal models, and more recently in humans. Several modes of action have been proposed, namely, inhibition of oxidative stress and damage, activation of metabolizing liver enzymes involved in carcinogen detoxification processes, and anti-inflammatory effects. The antioxidant activity of coffee relies partly on its chlorogenic acid content and is increased during the roasting process. Maximum antioxidant activity is observed for medium-roasted coffee. The roasting process leads to the formation of several components, e.g., melanoidins, which have antioxidant and anti-inflammatory properties. Coffee also contains two specific diterpenes, cafestol and kahweol, which have anticarcinogenic properties. Roasted coffee is a complex mixture of various chemicals. Previous studies have reported that the chemopreventive components present in coffee induce apoptosis, inhibit growth and metastasis of tumor cells, and elicit antiangiogenic effects. A meta-analysis of epidemiological studies showed that coffee consumption is associated with a lower risk of developing various malignant tumors. This review summarizes the molecular mechanisms and the experimental and epidemiological evidence supporting the chemopreventive effect of coffee.Key words: coffee - chemoprevention - antioxidative enzyme - detoxification enzyme - anti-inflammatory effect The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers.Submitted: 11. 9. 2016Accepted: 24. 11. 2016.

Potential of the Flavonoid Quercetin to Prevent and Treat Cancer – Current Status of Research

Naturally occurring bioactive compounds are promising candidates to prevent and treat cancer. Quercetin is a well-known plant flavonoid that is reported to have anticancer actions in vitro and in vivo. This review focuses on the molecular mechanisms underlying the chemopreventive effect of quercetin and its therapeutic potential in oncology. Quercetin elicits biphasic, hormetic, dose-dependent effects. It acts as an antioxidant and thus elicits chemopreventive effects at low concentrations, but functions as a pro-oxidant and may therefore elicit chemotherapeutic effects at high concentrations. Quercetin has multiple intracellular molecular targets with the potential to reverse treatment resistance and affect pleiotropic signaling processes that are altered in cancer cells. Studies suggest that quercetin binds to several receptors that play important roles in carcinogenesis, regulates expression of various genes, induces epigenetic changes, and interferes with enzymes that metabolize chemical carcinogens. In addition, it also elicits anti-inflammatory and antiviral effects. The ability of quercetin to induce apoptosis of cancer cells without affecting non-cancer cells has been documented using various cell lines. Quercetin also has antiangiogenic and antimetastatic properties. When used in combination with chemotherapy and radiotherapy, quercetin can act as a sensitizer and protect non-cancer cells from the side effects of currently used cancer therapies. The safety and potential usefulness of quercetin for the prevention and treatment of cancer have been documented in both animal experiments and a phase I clinical trial. Current studies are focused on nano-formulations to overcome the low bioavailability of natural quercetin, which limits its clinical use as an antitumor agent. Key words: quercetin - flavonoid - chemoprevention - oxidative stress - apoptosis - antitumor agent - cancer therapy - cancer The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers. Submitted: 22. 1. 2018 Accepted: 16. 4. 2018.

Metastases of a Breast Cancer to Skull Base

BACKGROUND Breast cancer (BC) is a frequent malignant disease which tends to develop distant metastases, but only very rarely in the head and neck region. CASE REPORT We present two case reports of patients with metastases of invasive BC in this area. They are of different clinical manifestation with different time relation to the primary tumor and different symptomatology. In the case of the first patient, a few years without evidence of malignant disease after treatment of primary tumor in complete remission. In the case of the second patient, as the first symptom of undiagnosed disease. Metastases were clinically observed in the skull base and maxillary sinus, manifesting neurologically with foramen jugulare syndrome and orbital symptoms, resp. In both cases, correlations between histological and clinical findings were essential for diagnosis. Palliative multimodal treatment was then employed. CONCLUSION Metastases of BC in the head and neck region occur only very rarely. The extremely variable symptomatology depends on the location of the metastasis and the affected structures. This might be a pitfall for diagnostics, especially in cases of an unidentified primary breast tumor, which may result in a delay of correct diagnosis. In addition, the correlation between histopathological and clinical findings might be of great relevance in these cases. Key words: skull base metastasis - breast cancer - foramen jugulare syndrome.

Prognostic impact of combined immunoprofiles in oropharyngeal squamous cell carcinoma patients with respect to AJCC 8th edition

OBJECTIVES To examine combined immunoprofiles of epidermal growth factor receptor (EGFR), CD44, and p16 in oropharyngeal squamous cell carcinoma (OPSCC) and to correlate them with radiotherapy treatment outcomes and clinicopathological parameters. Prognostic impact of the American Joint Committee on Cancer (AJCC) 8th edition staging system in comparison with 7th edition was analyzed. METHODS The study included 77 OPSCC patients treated by definitive intensity-modulated radiotherapy (IMRT). Clinical staging was assessed according to the AJCC, both 7th and 8th edition. Immunohistochemical (IHC) analysis of CD44 and EGFR was performed on primary biopsy tumor tissues. To evaluate the HPV status, IHC detection of p16 was employed. RESULTS The AJCC 8th edition staging system revealed correlations between overall survival (OS), progression-free survival (PFS), locoregional control (LRC), and clinical stage. EGFR and CD44 positivity (+) and p16 negativity (-) were associated with clinical stage IV of the disease. CD44+ and EGFR+ OPSCC displayed worse OS and LRC, and these cases also showed the worst 3-year OS and LRC. Combined analysis of protein expressions identified an association between p16- and EGFR+, p16- and CD44+, EGFR+, and CD44+. Combined immunoprofiles CD44+/p16-, EGFR+/p16-, and EGFR+/CD44+ were associated with worst OS and LRC. CONCLUSIONS Combined immunoprofiles of p16, EGFR, and CD44 might provide valuable prognostic and predictive information for the individual OPSCC patients, especially in terms of response to IMRT and prediction of treatment outcomes. Application of the AJCC 8th edition staging for HPV+ OPSCC proved to improve hazard discrimination and prognostication of OPSCC.