TYPE OF ATM ABERRATION HAS A DIFFERENT IMPACT ON SURVIVAL PARAMETERS IN MANTLE CELL LYMPHOMA

Introduction: The ataxia–telangiectasia mutated (ATM) gene plays an important role in the cellular response to DNA damage. Whether different types of ATM aberrations (mutation and/or deletion of (del)11q) differentially affect survival in mantle cell lymphoma (MCL) has not yet been reported. Methods: We analyzed 160 consecutive MCL patients (pts) treated in two Czech university centers (Prague, Olomouc) from 11/2006 to 12/2021. Both fluorescence in situ hybridization (FISH) and next generation sequencing (NGS, Illumina), were performed in all pts to identify ATM and TP53 gene aberrations on tumoral tissue (peripheral blood, bone marrow); the cutoff value for ATM and TP53 mutation was 3% variant allele frequency. Peripheral blood and/or bone marrow had at least 5% MCL involvement as analyzed by flow cytometry. Variables were compared by chi-squared test. Kaplan-Meier method was used to calculate the probabilities of progression and overall survival (PFS, OS); the log rank test was used for univariate comparisons of survival curves. PFS and OS were calculated from the date of diagnosis. Results: The median age at diagnosis was 67 (30-87) years. All pts had advanced disease (IV). MIPI score was low, intermediate and high in 15.6%, 26.3% and 58.1% pts, respectively. Treatment approaches used were as follows: watch and wait in 5.0%, R-CHOP/R-CHOP-like in 50.6%, intensive R-HDAC-containing in 34.4% and non-anthracycline/palliative regimen in 10.0% of pts. Complete and partial response was achieved in 56.3% and 21.9% of pts, respectively. Stable and progressive disease was observed in 13.1% of pts. Almost 29% of pts underwent autologous stem cell transplant. Sixty percent of pts received rituximab maintenance. Overall, 71 (44.4%) and 68 (42.5%) pts had ATM and TP53 aberration(s) (del/mut/del+mut), respectively. Of these, 20 (12.5%) pts had aberrations in both genes. Disruption of ATM gene was related to B-symptoms (p≤0.005). Age, sex, ECOG PS, cytomorphology, Ki67 index, MIPI and treatment response did not correlate with ATM aberration. With a median follow-up of 3.8 years, 2-year PFS and 2-year OS in all pts was 58.1% and 74.6%, respectively. Median PFS in pts with ATM mutation, ATM deletion and ATM+TP53 aberration was not reached, 3.3 and 0.7 years, respectively (p ≤ 0.005). Median OS in pts with ATM mutation, ATM deletion and ATM+TP53 aberration was not reached, 5.6 and 0.9 years, respectively (p ≤ 0.005). No significant difference in OS was found between ATM mutated and wild-type pts. (Survival graph below) Keywords: aggressive B-cell non-Hodgkin lymphoma, diagnostic and prognostic biomarkers, indolent non-Hodgkin lymphoma The research was funded by: IGA_LF_2023_005, MH CZ DRO-VFN64165, IGA_LF_2023_010, MH_CZ-DRO (FNOL, 00098892) No conflicts of interests pertinent to the abstract.