TP53 mutations and IGHV in naïve chronic lymphocytic leukemia: retrospective analysis of data from a Spanish collaborative network

This retrospective study involving 225 centers assessed TP53 and IGHV molecular status and stereotyped BcR IG subsets in a large cohort of patients with CLL in Spain using data from the RED53 project. Three analytical reference centers determined the mutational status of treatment-naïve CLL patients requiring treatment following the ERIC guidelines between May 2016 and March 2021. Of 1097 patients included (58.4% men), 90.8% had unmutated TP53 . Of the 100 patients (9.2%) with mutated TP53 , most (97.0%) had single-hit TP53 mutations, of which 88.3% were pathogenic. IGHV-UM mutational status (57.8%) was slightly more common than IGHV-M (33.2%). Of patients with mutated TP53 , 66.7% had IGHV-UM and 30.0% IGHV-M. Stereotyped Ig BCR subsets were identified in 9.2% of patients, with the most frequent being CLL#1 (23.2%), CLL#2 (24.0%), and CLL#6 (10.7%). The frequencies of TP53 and IGHV mutations were similar to those reported in other international series. The RED53 project enabled molecular testing to be incorporated into routine practice to guide treatment decisions.