The oral, highly selective Bcl2 inhibitor venetoclax has substantially improved the therapeutic landscape of chronic lymphocytic leukemia (CLL). Despite the remarkable response rates in patients with relapsed/refractory (R/R) disease, acquired resistance is the leading cause of treatment failure, with somatic BCL2 mutations being the predominant genetic drivers underpinning venetoclax resistance. To assess the correlation between disease progression and the most common BCL2 mutations G101V and D103Y, sensitive (10⁻⁴) screening for the most common BCL2 mutations G101V and D103Y was performed in 67 R/R CLL patients during venetoclax single-agent or venetoclax–rituximab combination therapy. With a median follow-up time of 23 months, BCL2 G101V and D103Y were detected in 10.4% (7/67) and 11.9% (8/67) of the cases, respectively, with four patients harboring both resistance mutations. Ten out of eleven patients carrying BCL2 G101V and/or D103Y experienced relapse during the follow-up period, representing 43.5% of the cases (10/23) showing clinical signs of disease progression. All BCL2 G101V or D103Y variants were detected in patients receiving venetoclax as a continuous single-agent treatment while these mutations were not observed during or after fixed-duration venetoclax therapy. Targeted ultra-deep sequencing of BCL2 uncovered three additional variants in four patient samples obtained at relapse, suggesting convergent evolution and implying a cooperating role of BCL2 mutations in driving venetoclax resistance. This cohort is the largest R/R CLL patient population reported to date in which BCL2 resistance mutations were investigated. Our study demonstrates the feasibility and clinical value of sensitive screening for BCL2 resistance mutations in R/R CLL.

TP53 aberrations predict chemoresistance and represent a contraindication for the use of standard chemoimmunotherapy in chronic lymphocytic leukaemia (CLL). Recent next‐generation sequencing (NGS)‐based studies have identified frequent low‐burden TP53 mutations with variant allele frequencies below 10%, but the clinical impact of these low‐burden TP53 mutations is still a matter of debate. In this study, we aimed to scrutinise the subclonal architecture and clinical impact of TP53 mutations using a sensitive, NGS‐based mutation analysis in a ‘real‐world’ cohort of 901 patients with CLL. In total, 225 TP53 mutations were identified in 17.5% (158/901) of the patients; 48% of these alterations represented high‐burden mutations, while 52% were low‐burden TP53 mutations. Low‐burden mutations as sole alterations were identified in 39% (62/158) of all mutated cases with 82% (51/62) of these being represented by a single low‐burden TP53 mutation. Patients harbouring low‐burden TP53 mutations had significantly lower time to first treatment compared to patients with wild‐type TP53. Our study has expanded the knowledge on the frequency, clonal architecture, and clinical impact of low‐burden TP53 mutations. By demonstrating that patients with sole low‐burden TP53 variants represent more than one‐third of patients with TP53 mutations and have an increased risk for treatment initiation, our findings strengthen the need to redefine the threshold of TP53 variant reporting to below 10% in the routine diagnostic setting.

In recent years, targeted therapies have become the standard of care for refractory/relapsed mantle cell lymphoma (MCL). Although the mutational profile of MCL has been extensively studied, there is a lack of understanding of resistance mechanisms and genetic factors that impact the response to novel treatments. Since patients relapsing on targeted treatment experience poor clinical outcomes, understanding the genetic foundation of resistance mechanisms in MCL is essential. In this study, we aimed to scrutinize the copy number profile and clonal dynamics of double‐resistant MCL patients treated sequentially with Bruton's tyrosine kinase inhibitor (BTKi) and venetoclax using low‐coverage whole genome sequencing (lcWGS). Samples obtained after systemic therapy showed more copy number alterations (CNAs) (p = 0.039; Wilcoxon) compared to samples collected before treatment initiation. Patients showing early progression on BTKi demonstrated CNAs affecting cytobands encompassing the coding regions of NOTCH1, TRAF2, BIRC2, BIRC3, and ATM. A deletion in chromosome 9p21.3 was identified in two out of three venetoclax‐resistant patients. For patient MCL2, progressing on ibrutinib but showing venetoclax resistance, a 9p21.3 deletion was found throughout the disease course, with acquired SMARCA4‐del(19)(p13.3–q13.11) and DLC1–del(8)(p23.2–q11.1) observed at relapse, highlighting their role in disease progression and therapy resistance. Using lcWGS, an innovative genome‐wide approach, this study revealed novel putative primary and acquired resistance mechanisms in BTKi and venetoclax double‐resistant MCL patients. © 2025 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

"Az immunglobulin-nehézláncgén variábilis régió (IGHV) mutációs státuszának meghatározása új generációs szekvenálással krónikus limfocitás leukémiában" published on 15 Dec 2023 by Akadémiai Kiadó.

"Konferenciabeszámoló: ERIC PRECEPTORSHIP (Realizing precision medicine in CLL: Why and how)" published on 03 Jun 2024 by Akadémiai Kiadó.

"Újdonságok a CLL, az FL és a DLBCL kezelésében és diagnosztikájában" published on 18 Jul 2023 by Akadémiai Kiadó.