ZEB1 as an additional predictor of tumor progression in Ewingʼs sarcoma. Results of a morphological study on a population of children and adolescents

Relevance. Ewingʼs sarcoma (ES) is a classic representative of the extensive family of ES tumors, which occupies one of the leading positions among the malignant pathology of the musculoskeletal system in children and adolescents. This group is characterized by an extremely large variety of morphological, immunohistochemical, and molecular genetic characters among its representatives. The absence of specific pathognomonic markers for ES, as well as the presence of wide variability of clinical manifestations complicates the differential diagnosis. Materials and methods. The study included patients of childhood and adolescence with a localized and generalized form of ES/PNEТ of various localizations undergoing treatment in the conditions of the Department of Pediatric Oncology of the Federal State Budgetary Research Center for Oncology from 2009 to 2019. As the material, the tissue of the primary tumor of ES/PNEТ from paraffin blocks was used, obtained from 67 patients during the primary biopsy, as well as after the surgical stage as part of a combined or complex treatment. The expression of ZEB1 was determined immunohistochemically.Results. The highest average level of expression of ZEB1 protein was observed in group 4 with a generalized form of ES (surgical material) and amounted to 60.8 ± 2.2 %, the minimum level was detected in group 2 with a localized form of ES (surgical material) and amounted to 29.2 ± 3.0 %. Between groups 2 (localized form) and 4 (generalized form) statistically significant differences were noted (p = 0.026).Conclusion. As a result of an immunohistochemical study, the ZEB1 protein showed its prognostic significance when comparing groups with a localized and generalized form of ES (p = 0.026). The predominance of the expression level of ZEB1 protein in the group with the generalized form statistically significantly increased the chances of metastasis by 3.6 times (95 % CI 1.13-11.8).