Uncommon EGFR Mutations in Non-Small Cell Lung Cancer and Their Impact on the Treatment.

BACKGROUND: Epidermal growth factor receptor (EGFR) mutations play an important role in the pathogenesis of non-small cell lung cancer. Because these alterations are so-called targetable mutations, their identification is important in daily clinical practice. The diagnostic standard of EGFR mutations is currently based on polymerase chain reaction methods, particularly the quantitative real-time polymerase chain reaction. In recent years, new generation sequencing has become increasingly important. In patients with EGFR mutations, a significant improvement in therapeutic outcomes was achieved with the administration of targeted therapy using tyrosine kinase inhibitors. EGFR is composed of four domains: extracellular with a ligand binding site, a transmembrane domain, a cytoplasmic tyrosine kinase catalytic domain, and a C-terminal domain. The key structures of the tyrosine kinase domain responsible for signal activation and transmission are encoded within exons 18-21 on chromosome 7. EGFR mutations are highly heterogeneous. About 90% of EGFR mutations are deletions of exon 19 and point mutation L858R in exon 21. These are referred to as classic mutations. Approximately 10% of the total number of EGFR mutations is attributable to less frequent alterations in the EGFR gene. Due to the low incidence of non-small cell lung cancer with less frequent EGFR mutations, information on their predictive significance is still incomplete. Most of the data for the treatment of cases with uncommon mutations were gathered from retrospective analyses and evaluations of small cohorts. PURPOSE: The aim of this review is to summarise the current options for diagnosing and treating non-small cell lung cancer patients with uncommon EGFR mutations. This work was supported by the MEYS - NPS I - LO1413 and MH CR - DRO (MMCI, 00209805). 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: 2. 6. 2019 Accepted: 26. 8. 2019.

[Malignant Melanoma - from Classical Histology towards Molecular Genetic Testing]. / Maligní melanom - od klasické histologie k molekulárne genetickému testování.

BACKGROUND: Malignant melanoma is - in comparison with other skin tumors - a relatively rare malignant neoplasm with highly aggressive biologic behavior and variable prognosis. Recent data in pathology and molecular diagnostics indicate that malignant melanoma is in fact not a single entity but a group of different neoplasms with variable etiopathogenesis, biologic behavior and prognosis. New therapeutic options using targeted treatment blocking MAPK signaling pathway require testing of BRAF gene mutation status. This helps to select patients with highest probability of benefit from this treatment. AIM: This article summarizes information on the correlation of morphological findings with genetic changes, discusses the representation of individual genetic types in various morphological subgroups and deals with the newly proposed genetic classification of melanoma and the current possibilities, pitfalls and challenges in BRAF testing of malignant melanoma. It also describes the current testing situation in the Czech Republic - the methods used, the representation of BRAF mutations in the tested population and the future of testing. It also shows the limitations of the BRAF and MEK targeted treatment concept resulting from the heterogeneity of the tumor population. Mechanisms of acquired resistance to MAPK pathway inhibitors, possibilities of their detection, and issues of combination of targeted therapy and immunotherapy are discussed.Key words: malignant melanoma - BRAF - mutation - molecular targeted therapy - tumor microenvironment - tumor heterogeneity This work was supported by projects PROGRES Q40/11, BBMRICZ LM2015089, SVV 260398 and GACR 17-10331S. 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: 28. 3. 2017Accepted: 16. 5. 2017.

[Molecular predictive markers of EGFR-targeted therapy in metastatic colorectal cancer]. / Molekulární prediktory cílené anti-EGFR terapie u metastatického kolorektálního karcinomu.

The monoclonal antibodies panitumumab and cetuximab that target the epidermal growth factor receptor are effective in approximately 10% and 20% of EGFR expressing, chemotherapy resistant metastatic colorectal cancer patients in monotherapy and in combination with chemotherapy, respectively. The evidence that EGFR expression by immunohistochemistry does not predict clinical outcome in EGFR targeted treatment has led to an intensive search for additional predicitive biomarkers. Oncogenic activation of signalling pathways downstream of the EGFR, such as mutation of KRAS, BRAF, or PIK3CA oncogenes, or inactivation of the PTEN tumor supressor gene is central to the progression of colorectal cancer. Tumor KRAS mutation, which may be present in 35%-45% of patients with colorectal cancer, is now recognized as an important predictive marker of resistance to cetuximab or panitumumab treatment and is also widely used in clinical practice. Among tumors carrying wild-type KRAS, mutations of BRAF or PIK3CA or loss of PTEN expression may be associated with resistance to the anti-EGFR monoclonal antibody treatment. On the other hand, EGFR ligands overexpression detected in tumor tissue is a promising positive predictive marker. There are also some initial observations that gene expression profiling could also contribute to clinical decision-making about the cetuximab and panitumumab treatments. These observations require further validation in prospective clinical trials before incorporation into clinical practice.

Mutations in EGFR signal pathway in correlation with response to treatment of head and neck cancers.

UNLABELLED: The prognostic and predictive value of the epidermal growth factor receptor (EGFR) expression and some genetic alterations in an EGFR signal pathway, such as the EGFR amplification, the EGFR activating tyrosine kinase domain mutations or the k-ras gene mutation were investigated in our study. The aim of the research was to evaluate the occurrence of the above-mentioned biomarkers in correlation with a therapeutic response and survival in patients with locoregionally advanced spinocellular head and neck cancers. KEYWORDS: Head and neck cancer, EGFR, predictive marker, k-ras, EGFR amplification, EGFR tyrosine kinase domain mutation.

The status and role of ErbB receptors in human cancer.

Changes in the expression of cellular receptors contribute to the progression of many types of solid tumors. In this review, we focus on the normal role of ErbB receptors as signal transducers and their contribution to carcinogenesis when there are abnormalities in ErbB signaling due to the overactivity of the receptors or the overexpression of ligands, which can lead to developmental defects and have been associated with many types of cancers.