{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,12,12]],"date-time":"2025-12-12T05:21:42Z","timestamp":1765516902114,"version":"3.48.0"},"reference-count":29,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2025,12,10]],"date-time":"2025-12-10T00:00:00Z","timestamp":1765324800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["CIMB"],"abstract":"<jats:p>Chronic lymphocytic leukemia (CLL) is the most common leukemia in Western countries, and B-cell receptor (BCR) pathway inhibitors such as idelalisib and ibrutinib are currently established therapies for CLL. Although effective, these drugs frequently lead to resistance, but the mechanisms are still not fully understood. Activation-induced cytidine deaminase (AID) is a B-cell enzyme essential for antibody diversification. However, it can also introduce off-target mutations, leading to genomic instability. This study investigates whether treatment with BCR pathway inhibitors increases AID activity in CLL and whether this activity contributes to the development of drug resistance. Peripheral blood samples from CLL patients were collected before and after treatment with idelalisib or ibrutinib. Targeted sequencing was used to identify mutations in known AID off-target genes. Concurrently, AID-wild type (AID-WT) and AID-knockout (AID-KO) CLL cell lines were established and subsequently exposed to escalating doses of BCR pathway inhibitors to develop drug-resistant models. In patient samples, treatment with BCR pathway inhibitors was associated with an increase in AID-dependent mutations in off-target genes, including BCL2, MYC, and IRF8. The in vitro models efficiently recapitulated the patients\u2019 data, as only AID-WT CLL cells accumulated mutations in the same AID off-target genes after drug exposure. However, no mutations were detected in genes that could mediate drug resistance. We conclude that BCR pathway inhibitors enhance AID mutational activity in CLL, but this does not appear to be directly involved in driving drug resistance. AID-targeted loci may nonetheless serve as biomarkers for monitoring genomic instability during treatment and inform further study.<\/jats:p>","DOI":"10.3390\/cimb47121031","type":"journal-article","created":{"date-parts":[[2025,12,10]],"date-time":"2025-12-10T15:32:17Z","timestamp":1765380737000},"page":"1031","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Evaluation of the Role of AID-Induced Mutagenesis in Resistance to B-Cell Receptor Pathway Inhibitors in Chronic Lymphocytic Leukemia"],"prefix":"10.3390","volume":"47","author":[{"given":"Chiara","family":"Pighi","sequence":"first","affiliation":[{"name":"Department of Molecular Biotechnology and Health Sciences, University of Turin, 10126 Turin, Italy"},{"name":"IRCCS Sacro Cuore Don Calabria Hospital, Department of Pathology, Negrar di Valpolicella, 37024 Verona, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1665-3594","authenticated-orcid":false,"given":"Alessandro","family":"Gasparetto","sequence":"additional","affiliation":[{"name":"Department of Molecular Biotechnology and Health Sciences, University of Turin, 10126 Turin, Italy"},{"name":"Department of Pathology, Children\u2019s Hospital Boston, Harvard Medical School, Boston, MA 02115, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9624-0337","authenticated-orcid":false,"given":"Elisa","family":"Genuardi","sequence":"additional","affiliation":[{"name":"Department of Molecular Biotechnology and Health Sciences, University of Turin, 10126 Turin, Italy"},{"name":"Division of Hematology, A.O.U. Citt\u00e0 della Salute e della Scienza di Torino, 10126 Turin, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0100-1489","authenticated-orcid":false,"given":"Jianli","family":"Tao","sequence":"additional","affiliation":[{"name":"Department of Pathology, Children\u2019s Hospital Boston, Harvard Medical School, Boston, MA 02115, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Qi","family":"Wang","sequence":"additional","affiliation":[{"name":"Department of Pathology, Children\u2019s Hospital Boston, Harvard Medical School, Boston, MA 02115, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2592-8724","authenticated-orcid":false,"given":"Candida","family":"Vitale","sequence":"additional","affiliation":[{"name":"Department of Molecular Biotechnology and Health Sciences, University of Turin, 10126 Turin, Italy"},{"name":"Division of Hematology, A.O.U. Citt\u00e0 della Salute e della Scienza di Torino, 10126 Turin, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1589-1195","authenticated-orcid":false,"given":"Valentina","family":"Griggio","sequence":"additional","affiliation":[{"name":"Department of Molecular Biotechnology and Health Sciences, University of Turin, 10126 Turin, Italy"},{"name":"Division of Hematology, A.O.U. Citt\u00e0 della Salute e della Scienza di Torino, 10126 Turin, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4198-9620","authenticated-orcid":false,"given":"Rocco","family":"Piazza","sequence":"additional","affiliation":[{"name":"Department of Medicine and Surgery, University of Milano-Bicocca, 20126 Milan, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Sabino","family":"Ciavarella","sequence":"additional","affiliation":[{"name":"Hematology Unit, Oncology Department, IRCCS Istituto Tumori \u201cGiovanni Paolo II\u201d, 70124 Bari, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Marta","family":"Coscia","sequence":"additional","affiliation":[{"name":"Hematology Division, ASST Sette Laghi, Ospedale di Circolo, 21100 Varese, Italy"},{"name":"Department of Medicine and Surgery, University of Insubria, 21100 Varese, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9711-1502","authenticated-orcid":false,"given":"Simone","family":"Ferrero","sequence":"additional","affiliation":[{"name":"Department of Molecular Biotechnology and Health Sciences, University of Turin, 10126 Turin, Italy"},{"name":"Division of Hematology, A.O.U. Citt\u00e0 della Salute e della Scienza di Torino, 10126 Turin, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6203-7966","authenticated-orcid":false,"given":"Alberto","family":"Zam\u00f2","sequence":"additional","affiliation":[{"name":"Institute of Pathology, University of W\u00fcrzburg, 97080 W\u00fcrzburg, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1324-1431","authenticated-orcid":false,"given":"Claudia","family":"Voena","sequence":"additional","affiliation":[{"name":"Department of Molecular Biotechnology and Health Sciences, University of Turin, 10126 Turin, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1564-8531","authenticated-orcid":false,"given":"Roberto","family":"Chiarle","sequence":"additional","affiliation":[{"name":"Department of Molecular Biotechnology and Health Sciences, University of Turin, 10126 Turin, Italy"},{"name":"Department of Pathology, Children\u2019s Hospital Boston, Harvard Medical School, Boston, MA 02115, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2025,12,10]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"334","DOI":"10.1182\/bloodadvances.2020003423","article-title":"Overcoming Resistance to Targeted Therapies in Chronic Lymphocytic Leukemia","volume":"5","author":"Mato","year":"2021","journal-title":"Blood Adv."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"284","DOI":"10.3324\/haematol.2019.241539","article-title":"Comparative Analysis of Targeted Novel Therapies in Relapsed, Refractory Chronic Lymphocytic Leukemia","volume":"106","author":"Eyre","year":"2020","journal-title":"Haematologica"},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Ondrisova, L., and Mraz, M. 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