BCR::ABL1-like acute lymphoblastic leukaemia: a single institution experience on identification of potentially therapeutic targetable cases.

BACKGROUND: BCR::ABL1-like acute lymphoblastic leukaemia (BCR::ABL1-like ALL) is characterized by inferior outcomes. Current efforts concentrate on the identification of molecular targets to improve the therapy results. The accessibility to next generation sequencing, a recommended diagnostic method, is limited. We present our experience in the BCR::ABL1-like ALL diagnostics, using a simplified algorithm. RESULTS: Out of 102 B-ALL adult patients admitted to our Department in the years 2008-2022, 71 patients with available genetic material were included. The diagnostic algorithm comprised flow cytometry, fluorescent in-situ hybridization, karyotype analysis and molecular testing with high resolution melt analysis and Sanger Sequencing. We recognized recurring cytogenetic abnormalities in 32 patients. The remaining 39 patients were screened for BCR::ABL1-like features. Among them, we identified 6 patients with BCR::ABL1-like features (15.4%). Notably, we documented CRLF2-rearranged (CRLF2-r) BCR::ABL1-like ALL occurrence in a patient with long-term remission of previously CRLF2-r negative ALL. CONCLUSIONS: An algorithm implementing widely available techniques enables the identification of BCR::ABL1-like ALL cases in settings with limited resources.

Harmonization of Flow Cytometric Minimal Residual Disease Assessment in Multiple Myeloma in Centers of Polish Myeloma Consortium.

Minimal residual disease (MRD) status is now considered as one of the most relevant prognostic factors in multiple myeloma (MM) while MRD negativity became an important endpoint in clinical trials. Here, we report the results of the first study evaluating the reproducibility of high-sensitivity flow cytometry MM MRD assessment in four laboratories in Poland. EuroFlow protocols for instrument setting standardization and sample preparation in MM MRD assessment were implemented in each laboratory. In the inter-laboratory reproducibility study, 12 bone marrow samples from MM patients were distributed and processed in participant laboratories. In the inter-operator concordance study, 13 raw data files from MM MRD measurements were analyzed by five independent operators. The inter-laboratory study showed high 95% overall concordance of results among laboratories. In the inter-operator study, 89% of MRD results reported were concordant, and the highest immunophenotype interpretation differences with regard to expression of CD27, CD45, CD81 were noticed. We confirmed the applicability and feasibility of the EuroFlow protocol as a highly sensitive method of MRD evaluation in MM. Results of our inter-center comparison study demonstrate that the standardization of MM MRD assessment protocols is highly desirable to improve quality and comparability of results within and between different clinical trials.

The diagnostic and prognostic significance of flow cytometric bone marrow assessment in myelodysplastic syndromes according to the European LeukemiaNet recommendations in single-centre real-life experience.

INTRODUCTION: This analysis attempts to determine the diagnostic and prognostic value of bone marrow (BM) evaluation by multiparameter flow cytometry in patients with myelodysplastic syndrome (MDS). MATERIALS AND METHODS: The study group consisted of patients who underwent diagnostic process in the years 2008-2017 due to cytopenia and finally were diagnosed with MDS (n = 71). The comparative group included patients with cytopenia diagnosed in the same period, whose definitive diagnosis was other than MDS (n = 39). Flow cytometric evaluation of BM was performed following the recommendations of the European LeukemiaNet (ELN) in all patients. RESULTS: The median number of immunophenotypic abnormalities found on granulocytes in the MDS group was significantly higher compared to the comparative group [2 (range 0-5) vs 0 (range 0-2); P < .0001]. Similarly, the median Ogata score was significantly higher in the MDS group [2 (range 0-4) vs 1 (range 0-3); P < .0001]. Since the disturbances of the CD11b/HLA-DR and CD11b/CD13 on granulocytes were significantly more common in MDS patients, the Ogata score was extended by these abnormalities, what resulted in its higher diagnostic sensitivity (82%) while preserving high specificity (87%). The positive correlation was found between risk score determined by the Revised International Prognostic Scoring System and the number of the BM immunophenotypic abnormalities (P = .017). CONCLUSIONS: Our results indicate that the diagnostic usefulness of the Ogata score may be increased by including the abnormal expression of CD11b/HLA-DR and CD11b/CD13 on granulocytes. Moreover, our findings suggest the prognostic significance of the number of BM cytometric abnormalities in MDS.

The prognostic significance of surface dipeptidylpeptidase IV (CD26) expression in B-cell chronic lymphocytic leukemia.

A number of factors related to B-cell chronic lymphocytic leukemia (B-CLL) patients' prognosis have been identified. However, still some factors better reflecting disease activity in individual cases are explored. The study aimed to evaluate prognostic significance of dipeptidylpeptidase IV/CD26 expression on B-CLL cells and its relationship with other well established prognostic factors. The study included 94 patients with newly diagnosed B-CLL and involved analysis of clinical, laboratory, flow-cytometry and cytogenetic data. Detailed analysis showed that CD26 expression on B-CLL cells correlates with Rai's clinical stage of the disease at diagnosis (p=0.034), ß2-microglobulin concentration (p=0.012), lactic acid dehydrogenase activity (p=0.045) and absolute lymphocytes' count (p=0.027) in the blood. The multivariate analysis revealed that time to treatment (TTT) was significantly influenced by Rai clinical stage, LDH activity in blood and CD26 expression on B-CLL cell's. Moreover, in the multivariate analysis restricted to the group of patients with documented cytogenetic risk (n=36) CD26 expression, Rai clinical stage and cytogenetic profile remained their independent impact on TTT. The results of our study indicate that the CD26 expression should be incorporated in B-CLL patients risk assessment along with well known prognostic factors, since it seems to have a relationship with the tumor mass and influences TTT.