Publication Date:
2018-11-29
Description:
Background: Somatic driver mutations in hematopoietic cells may lead to clonal hematopoiesis of indeterminate potential (CHIP). In patients with lymphoma CHIP has been associated with increased risk of therapy-related myeloid neoplasms (tMN) and inferior survival after autologous stem cell transplantation as demonstrated in a large single center study and in a case-control study (Gibson CJ et al., JCO 2017 and Berger G et al., Blood 2018). Here, we investigated the clinical impact of clonal hematopoiesis in a nation-wide population-based cohort of Danish lymphoma patients undergoing autologous transplant with prospective data from four national patient registries. Methods: Patients with lymphoma who had undergone leukapheresis at all danish transplant centers from 2000 to 2012 were identified. DNA and RNA was extracted from mobilized peripheral blood products. Targeted sequencing of all samples was performed using an Illumina TruSeq Custom Amplicon panel (Illumina, San Diego, CA, USA) designed to cover 〉95% of mutations associated with CHIP (ASXL1, ASXL2, BCOR, BRCC3, CBL, CREBBP, DNMT3A, ETV6, GNB1, IDH1, IDH2, JAK2, KRAS, NRAS, PPM1D, RAD21, SF3B1, SRSF2, TET2, TP53). To allow detection of low-level mutations and secure variant calling, unique molecular identifiers (UMI's) were used. Filtering of variants was done by stringent criteria consistent with earlier studies. Assessment of mutations was performed blinded to the patients' clinical data. Prospective clinical patient data was obtained for all patients from four national registries, including the Danish Lymphoma Registry (diagnosis, involvement, lymphoma treatment, relapse and death), the Danish National Patient Registry (hospital admission diagnoses and treatments), the Danish Cancer Registry (primary and secondary cancer diagnoses) and the Danish Pathology Database (histopathological examinations and diagnoses), respectively. Results: Samples from 574 patients were included. The median age was 55.5 years (IQR: 45.3 - 62.2) and the median follow-up time for survivors was 9.2 years (IQR: 7.1 - 11.2). The lymphoma subtypes were typical of patients selected for autologous transplantation; diffuse large B-cell lymphoma (191 pts), follicular lymphoma (102 pts), mantle cell lymphoma (88 pts), Hodgkin's lymphoma (80 pts), peripheral T-cell lymphoma (77 pts) and other histologies (36 pts). Of the 574 patients analyzed, 191 (33.3%) of the patients had somatic mutations meeting CHIP criteria (total mutations called=210). The most commonly mutated genes were DNMT3A (n=59, 28%), TET2 (n=48, 23%), PPM1D (n=34, 16%), ASXL1 (n=21, 10%) and TP53 (n=18, 8%). As expected CHIP mutations were more frequent in patients above 60 years (p=0.002). Prevalence of CHIP was associated with an inferior overall survival (p=0.004) and event-free survival (p=0.03). It was also associated with increased risk of biopsy-confirmed tMN (p=0.03) and higher probability of receiving blood transfusions after autologous transplant (p=0.027). Especially patients with mutations in DNA damage response genes PPM1D and TP53 (found in 48 pts, 8.3%) had a significantly increased risk of adverse outcomes. Both overall survival and event-free survival were significantly poorer with the presence of DNA damage pathway mutations (p
Print ISSN:
0006-4971
Electronic ISSN:
1528-0020
Topics:
Biology
,
Medicine
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