Novel Aspects of Genetics, Molecular Biology and Clinical Oncology of Sarcomas.

The Connective Tissue Oncology Group Annual Meeting 2018 (CTOS 2018) took place in Rome from 4 to 17 November 2018, and the 39th Plenary Meeting of the Scandinavian Sarcoma Group (SSGM 2019) was held in Bergen from 8 to 10 May 2019. These two large international conferences brought together an overwhelming majority of molecular and clinical specialists in the sarcoma field, especially those working on soft tissue sarcoma. Topics discussed on the conferences included, among others, sarcoma genetics, clinical and molecular subclassification, targeted therapy, clinical prognostication, and new experimental sarcoma models. A large ongoing international study on germinal sarcoma genetics was presented, the interim results of which revealed the extremely complex nature of genetic disposition to sarcoma, and, surprisingly, a rather prominent place among predisposing genes for those coding for structural telomere constituents. Fusion oncogenes dominate somatic sarcoma genetics, especially because of their origin and impact on sarcoma clinical behaviour, and are especially relevant for karyotypically simple paediatric sarcomas. A crucial issue in karyotypically complex sarcomas are the efforts being made to obtain a subclassification of sarcoma, other than those based on pathology, using either the clinical characteristics of sarcomas (uterine leiomyosarcoma vs. soft tissue leiomyosarcoma) or specific gene expression profiles (molecular subtypes in undifferentiated pleiomorphic sarcoma), which showed that molecular characterization can open the way for subtype specific therapies. Other examples of where this type of strategy can be applied include gastrointestinal stromal tumours, infantile fibrosarcoma, and inflammatory myofibroblastic tumours, where targeted therapy could be conceived based on the actionable mutations identified. Attempts in this direction have been made also for clear cell sarcoma and dedifferentiated liposarcoma, albeit the effectiveness of molecular-targeted treatments for these sarcomas is still poor, and progress in the treatment of osteosarcoma is still rather slow. Actually, the platelet-derived growth factor signalling system holds a prominent position in searches for targeted therapies, not only against rare sarcoma types, where are activated by mutations (some gastrointestinal stromal tumours, infantile hereditary myofibromatosis, and dermatofibrosarcoma protuberans), but also against other more usual sarcoma types, where the blocking anti-PDGFRα-antibody olaratumab has been successfully integrated into combinatorial chemotherapeutic regimens. In the field of clinical prognostication, remarkable progress in sarcoma nomograms was reported. Interesting results were also presented in the area of new experimental sarcoma models. Participation on both scientifi c conferences and all the experimental work leading to the presented sarcoma models were supported by the Czech Science Foundation project No. 17-17636S. 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: 20. 9. 2019 Accepted: 6. 11. 2019.

Can the One-Step Nucleic Acid Amplification method of lymph nodes examination make the staging of pulmonary tumours more precise?

INTRODUCTION: The aim of this article is to compare the sensitivity of detecting micrometastases in hilar and mediastinal lymph nodes in case of primary (non-small cell) and secondary (metastases of colorectal carcinoma) pulmonary tumours using standard histopathological examination with haematoxylin-eosin staining, immunohistochemistry examination with Anti-Cytokeratin 19 antibody and examination based on the One-Step Nucleic Acid Amplification method. METHOD: During radical surgical treatment of primary non-small cell lung carcinoma and pulmonary metastases of colorectal carcinoma, hilar and mediastinal lymph nodes of 100 patients enrolled in the study in the period from 2015 to 2017 were extracted based on a standard classification. These lymph nodes were subsequently divided along the longitudinal axis into 4 identical parts where part one and three on the left were intended for examination based on the One-Step Nucleic Acid Amplification method, whereas parts two and four were subjected to histopathological examination. In evaluating the respective parts of the nodes by histological examination, the nodes were first examined by a standard procedure that involves haematoxylin-eosin staining, followed by immunohistochemistry examination with Anti-Cytokeratin 19 antibody. The One-Step Nucleic Acid Amplification method was performed in the kit supplied by Sysmex (Kobe, Japan) and is based on the detection of cytokeratin 19 mRNA (messenger ribonucleic acid) by reverse transcription coupled with isothermal amplification. RESULTS: A total of 1,426 lymph nodes of the patients enrolled in the study were extracted and examined using the above mentioned methodology. In 78 patients (78%), identical results were obtained using haematoxylin-eosin staining, immunohistochemistry with Anti-Cytokeratin 19 and One-Step Nucleic Acid Amplification. Micrometastases in the lymph nodes using the One-Step Nucleic Acid Amplification method in the absence of the other methods were proven in 16 patients (16%). Only in 3 cases (3%), the examination by haematoxylin-eosin staining, or immunohistochemistry with Anti-Cytokeratin 19, was positive while One-Step Nucleic Acid Amplification was negative. The results obtained by immunohistochemistry with Anti-Cytokeratin 19 antibody were practically the same as those obtained by haematoxylin-eosin staining (97%). CONCLUSION: The results of the study have demonstrated a higher percentage of metastases detected in hilar and mediastinal lymph nodes if the One-Step Nucleic Acid Amplification method of examination was used compared to haematoxylin-eosin staining and immunohistochemistry with Anti-Cytokeratin 19 antibody (upstaging in 16%). This shows that the examination of lymph nodes using the One-Step Nucleic Acid Amplification method can have a certain potential to make the pulmonary tumours staging more accurate. On the other hand, immunohistochemistry with Anti-Cytokeratin 19 antibody seems to be not so useful. However, it is necessary to prove this hypothesis in follow-up studies, or where applicable, in a larger cohort of patients. Another task is to ascertain, by careful patient monitoring, the influence of the micrometastases detected in their lymph nodes using the One-Step Nucleic Acid Amplification method on these patients' follow-up. Key words: lung cancer - lymph nodes - H&E - IHC CK19 - OSNA assay.