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Background. TP53 gene mutations impede cell apoptosis and lead to additional oncogenic events contributing to tumor progression. Aim. To assess TP53 gene mutation rate in patients with high-grade B-cell lymphoma double-hit (HGBCL DH) and not otherwise specified (HGBL NOS); to analyse its relationship with disease prognosis. Materials & Methods. Retrospective materials from medical data of 10 HGBL DH and 26 HGBL NOS patients were analyzed. Median follow-up was 26.5 months (range 0.6-160.9 months). Selection was based on the presence of available biological materials (paraffin blocks) for Sanger sequencing of TP53 gene from exon 5 to exon 8 (encoding DNA-binding domain of TP53 gene). FISH analysis of the tumor was performed in all patients to identify translocations involving c-MYC/8q24, BCL2/18q21, and BCL6/3q27 gene locus. To analyze differences between groups χ2 and Mann-Whitney tests were applied. Univariate event analysis (Kaplan-Meier and log-rank tests) and Cox regression analysis were used to assess the influence of molecular markers on the disease prognosis. Results. TP53 gene mutations in lymphoma cells were found in 13 (36 %) out of 36 patients, 10 (77 %) out of 13 mutations were pathogenic. In 8 out of 10 patients with TP53 mutations c-MYC/8q24 gene translocation was identified. Groups with wild (TP53-WT) and mutant (TP53-MUT) types of TP53 gene were similar in terms of main clinical characteristics. Patients with TP53-MUT in tumor cells showed worse 3-year overall survival (OS) compared with the group without TP53-MUT (30 % vs. 73 %; p = 0.026) as well as higher probability of disease progression in the period of 3 years (66 % vs. 15 %; p = 0.004). In multivariate analysis significant OS predictor was the presence of TP53 mutation (p = 0.006). Relapse/ progression probability was higher in combined cases of TP53 mutation and translocation involving c-MYC gene locus (p = 0.0003). Conclusion. Translocation involving c-MYC gene along with TP53 gene mutation in tumor cells can serve as a criterion for dividing HGBL DH and HGBL NOS patients into different lymphoma relapse/progression risk groups.

Background. Grade 3 follicular lymphoma (FL) is a heterogenetic group of tumors. The selections of patients with similar characteristics of the tumor process is important for classification 3 grade forms of FL and risk stratification, as well as for the development of new therapeutic approaches. Different morphological, immunohistochemical and cytogenetical characteristics of the tumor result in different clinical forms of the disease. Aim. To describe the clinical, morphological, immunohistochemical and cytogenetical characteristics of grade 3 FL and evaluate their prognostic value for R-CHOP-21 chemotherapy. Materials & Methods. We performed retrospective and prospective analysis of morphological, immunohistochemical and genetical characteristics of 93 primary patients with grade 3 FL (21-78 years, median 53 years, women to men - 1:1.4) admitted to National Medical Hematology Research Center from years 2001 to 2016. Morphological and immunohistochemical assessment of the affected lymph nodes and bone marrow biopsy material was performed. Data obtained from the standard cytogenetic and FISH assessment were compared to identify the BCL2 rearrangement. Results. We proposed an algorithm for differential diagnosis of the 2 types of grade 3 FL: de novo FL (n = 22) and transformed FL (n = 21). De novo grade 3 FL had the immunophenotype of CD10- in 19 (86 %) cases, MUM1++ (monomorphically) in 19 (90 %), and BCL-2 in 5 (22 %). It was characterized by the absence of the BCL2 rearrangement (n = 22, 100 %) and bone marrow involvement (n = 14, 67 %) and/or bone marrow involvement (n = 7, 100 %). Third grade FL transformed from grades 1 or 2 had was CD10+ (n = 19, 90 %), MUM1+ (heterogeneously, n = 16, 76 %) or MUM1-(n = 4, 19 %), BCL-2+ (n = 20, 95 %) and had BCL2 rearrangement (n = 19, 90 %). Small cell bone marrow involvement was observed in 71 % of cases, whereas large cell involvement was seen predominantly in de novo FL (p = 0.06). The analysis showed that 5-year relapse-free survival in patients with grade 3 de novo FL after R-CHOP-21 therapy was 87 % compared to 16 % with transformed FL (p = 0.06) for the median 41 months of follow up. Conclusion. We described the morphological, immunohistochemical and cytogenetical characteristics of grade 3 de novo FL and grade 3 FL, transformed from grades 1 or 2. The described variants show different sensitivity to immunochemotherapy.