Clinical and transcriptomic characterization of patients with chronic lymphocytic leukemia harboring t(14;19): an ERIC study

: In chronic lymphocytic leukemia (CLL), the role of complex karyotype (CK) for prognostic stratification remains a topic of debate, and the impact of specific cytogenetic abnormalities is still unclear. This study aims to investigate the clinical and biological features of CLL with t(14;19)(q32;q13) (tCLL) involving the BCL3 gene. Patients with tCLL were younger and more commonly presented unmutated IGHV gene, subset #8 stereotypy, trisomy of chromosome 12, and complex karyotype than other patients without t(14;19) (oCLL). The presence of t(14;19) was associated with a shorter time to treatment and overall survival compared to oCLL. Gene expression analysis revealed a unique transcriptome profile in tCLL, characterized by the upregulation of BCL3 and the activation of B-cell receptor, PI3K-Akt. Conversely, apoptosis-related pathways were suppressed in tCLL. While the BTK gene was upregulated, the BCL2L11 gene, coding for the pro-apoptotic protein BIM, was downregulated. Notably, patients with tCLL were characterized by a trend (p = 0.058) for a longer time to the next treatment with BTK inhibitors (BTKi) compared to those treated with a venetoclax-based (Ven-based) regimen. We underscore the adverse outcomes of tCLL, its distinct molecular features and gene expression patterns. Therefore, our data suggest that identifying tCLL could help tailor therapeutic approaches.