Jevremović, Dragan

Abstract Background Central nervous system involvement in multiple myeloma (CNS-MM) is a rare but highly aggressive manifestation. Limited data exists regarding its incidence, biology, treatment patterns, and outcomes. A deeper understanding of the features unique to CNS-MM will help inform risk stratification and management strategies. Methods We conducted a retrospective study of CNS-MM patients at our institution between January 2000 and December 2023. We identified 305 MM patients with pathology-proven extramedullary disease (EMD). CNS involvement was defined as the presence of parenchymal (brain or spine) or leptomeningeal involvement by MM. Univariate analysis was performed to compare the clinical characteristics between EMD patients with and without CNS-MM. Results Out of 305 patients with EMD, we identified 22 patients with CNS-MM. Common symptoms prompting evaluation of CNS-MM were headaches (32%), numbness or tingling (32%), weakness (27%), confusion (23%), falls (23%), and visual disturbances (14%). Among these patients, 17 (77%) had detectable disease in cerebrospinal fluid (CSF), 12 (55%) in the brain parenchyma, 4 (18%) in the spinal cord parenchyma and 6 (27%) in the leptomeninges. Of the CNS-MM patients, the median age at diagnosis of MM was 58.3 years and the median time to CNS-MM involvement was 16.2 months, with 3 (14%) patients having CNS involvement at diagnosis. The predictors of CNS-MM development were high-risk cytogenetics (OR 2.9, p=0.04) and presence of additional visceral organ involvement outside of the CNS (OR 3.4, p=0.03). EMD was multifocal in 20 CNS-MM patients (83%) and visceral organ involvement [most commonly lymphadenopathy (27%), solid organ (18%) and pleural fluid (14%)] was present in 14 (64%) of these patients, compared to 54% in EMD patients without CNS-MM. High-risk cytogenetics [del(17p), 1q gain/amplification, t(4;14), t(14;16), t(14;20)] were seen in 16 (73%) patients, most commonly 1q gain or amplification (40%), t(4;14) (23%), and del(17p) (18%). Five (23%) exhibited a double-hit profile. In comparison, 113 (40%) EMD patients without CNS-MM had high risk cytogenetics. The median overall survival (OS) from diagnosis of CNS-MM was 6 months (95%CI:1.26-36) compared to 15.6 months (95%CI: 12-18) from diagnosis of EMD in EMD patients without CNS-MM (p=0.05). Median OS from diagnosis of MM in the CNS-MM cohort was 36 months (95%CI: 22.8-NA) compared to 55.2 months (95%CI: 45.6-68.4) in EMD patients without CNS-MM (P=0.11). When excluding CAR-T or bispecific therapy recipients, median OS from diagnosis of MM for CNS-MM was 22 months versus 48 months in EMD patients without CNS-MM (P=0.02). Overall response rate in our CNS-MM cohort with first treatment for EMD was 32% compared to 48% in EMD patients without CNS-MM (p=0.04). In patients with CNS-MM, median progression-free survival (PFS) from CNS-MM diagnosis was 3.3 months (95%CI: 0.8-12) versus 3.9 months (95%CI: 3-5.1) in EMD patients without CNS involvement (p=0.2). Six (27%) CNS-MM patients received CAR-T; 3 received cilta-cel, 2 received ide-cel and one received a BCMA CAR-T on trial. Bispecific therapy was used in 4 (18%) patients, with 2 receiving Teclistamab and 2 Talquetamab. Three (14%) CNS-MM patients received both CAR-T and bispecific therapy. The median PFS on CAR-T therapy was 10.5 (95%CI: 5.6-NA) months and 12.7 (95%CI: 10.2-NA) months on bispecific therapy. The median OS from diagnosis of CNS-MM for patients who received CAR-T or bispecific therapy was 36 months (95%CI: 14.0-NA), compared to 1.2 months (95%CI: 0-14.4) for those who did not (p=0.002). Six (27%) patients with CNS-MM, all of whom had CSF involvement of disease, received intrathecal therapy; methotrexate in 3, cytarabine in 2, and one receiving both. Two of these patients demonstrated improvement in cerebrospinal fluid findings following intrathecal chemotherapy, in conjunction with other therapies. Patients who received intrathecal chemotherapy had a median OS measured from development of EMD of 10.8 (95%CI: 3.6-NA) months, compared to 15 months (95%CI: 4.8-NA) in those without IT chemotherapy (p=0.59). Conclusion Central nervous system involvement in MM is relatively uncommon and associated with dismal outcomes. High-risk cytogenetics and involvement of other visceral sites are associated with a higher risk of CNS involvement. Intrathecal therapy offers limited value and immune effector therapies represent efficacious options for treatment.

Abstract Background: Isocitrate dehydrogenase (IDH) mutations are frequently implicated in the development of acute myeloid leukemia (AML). In a recent study (Salman MY, Blood Adv 2025), it was reported that IDH2 mutation subtypes, R140 and R172, may respond differently to intensive chemotherapy. In this study, we evaluated mid-cycle and end-of-cycle bone marrow blast responses in AML patients with IDH2 R140, IDH2 R172, and IDH1 R132 mutations, aiming to determine whether these subtypes exhibit different response dynamics. Methods: We reviewed the charts of AML patients diagnosed at Mayo Clinic, Rochester, between the years 2016 - 2023 that had available next generation sequencing (NGS) data. Institutional review board approval was obtained. All data were recorded at the time of AML diagnosis. Patients without molecular data or not treated with intensive chemotherapy (7+3 or CPX-351) were excluded from this study. Bone marrow blast percentages were assessed at mid-induction (days 14-21) and end of cycle (counts recovery). Blast clearance dynamics and complete remission rates were compared across IDH mutation subgroups and correlated with outcomes. GraphPad Prism 10.0.0 was used for statistical analysis. Results: Out of 381 AML patients, 31 had IDH2 mutations (23 with R140 and 8 with R172), and 8 had IDH1 mutations (all R132). Among patients with IDH2 mutations, those with R172 had numerically higher median mid-cycle bone marrow blast percentage compared to R140 (10% vs. 4%, p = 0.37). There was no significant difference in mid-cycle blast percentages between patients with IDH1 and IDH2 mutations (4.5% vs. 4%, p = 0.8). At mid-cycle, 68% of patients with IDH2 R140 had blast counts <5%, compared to 38% of those with IDH2 R172, suggesting a trend for faster mid-cycle clearance in the R140 group, though not statistically significant (OR 3.57, p = 0.2). In a broader comparison, 60% of IDH2-mutated patients and 50% of IDH1-mutated patients achieved blast clearance (blasts <5%) at mid-cycle, though not statistically significant (p = 0.7). At the end of the induction, patients with IDH2 R140 had significantly lower median bone marrow blast percentages compared to those with R172mutations (2% vs. 4%, p = 0.01). Similarly, patients with IDH1 mutations showed low blast counts compared to the IDH2 group (1.5% vs. 3%, p = 0.1). A higher proportion of IDH2 R140 patients achieved blast clearance compared to those with R172 mutations (100% vs. 75%, p = 0.06), while proportion of patients who achieved blast clearance were similar between IDH1 and IDH2 patients (87.5% vs 93.1%, P = 0.5). Analysis of overall complete remission rates (including both complete remission [CR] and CR with incomplete hematologic recovery [CRi]) within the IDH2-mutated group showed a higher rate in patients with the R140 mutation compared to those with R172 (87% vs. 75%), though the difference was not statistically significant (p = 0.5). When comparing IDH1- and IDH2-mutated patients, overall complete remission rates were 75% and 84%, respectively, with no significant difference observed (p = 0.6). Kaplan–Meier analysis of time to end-of-induction blast clearance revealed no statistically significant difference between IDH2 R140 and R172 patients (median time to clearance: 31 vs. 37 days, p = 0.3). Similarly, no difference was observed between IDH1 and IDH2-mutated patients (33 vs. 31 days, p = 0.9). Overall survival analyses showed no significant difference between IDH2 R140 and R172 groups (median 66.8 months vs not reached, P = 0.4). Likewise, no difference was observed between IDH1 and IDH2 patients (44.4 months vs not reached, P = 0.7), indicating similar overall survival across mutation subtypes. Conclusion: IDH2-R140 was associated with more effective blast cytoreduction following intensive induction compared to IDH2-R172. Although not statistically significant, IDH2 R172consistently showed trends toward higher blast percentages, delayed response, and lower overall complete remission rates. These findings align with the recent study reporting significantly slower blast reduction and delayed response in R172-mutated AML. Also, no significant differences were found between IDH1- and IDH2-mutated patients in terms of response kinetics or overall survival. Together, these findings highlight potential biological differences among IDH mutation subtypes that may impact treatment response and require further investigation in larger prospective cohorts.

Abstract Introduction: The ZRSR2 gene, located at Xp22.2, encodes a protein component of the RNA spliceosome. Alterations in ZRSR2 have been reported in various myeloid neoplasms (MN) and their precursors. They are frequently accompanied by other co-mutations, most commonly TET2. Isolated ZRSR2 mutations, however, are less commonly encountered and their clinicopathologic features have not been well documented. Aim: To describe the clinicopathologic features of MN and their precursors with isolated ZRSR2 mutations. Methods: Next-generation sequencing (NGS) was performed on peripheral blood (PB) or bone marrow (BM) samples from patients with confirmed/suspected MN using a 35-47 gene MN-targeting NGS panel. MN and clonal cytopenia of undetermined significance (CCUS) cases with isolated likely pathogenic/pathogenic (LP/P) ZRSR2 mutations were identified. Pathology diagnoses were rendered following the 2022 WHO/ICC classification and the slides were reviewed by three pathologists. Electronic medical records were reviewed for collection of relevant laboratory data. This study was approved by our institution's Institutional Review Board. Results: Of 164 ZRSR2-mutated cases, 10 cases with isolated LP/P mutations in ZRSR2 were identified. Patients were all male, with a median age 69.5 years. Three patients were diagnosed with CCUS, five with myelodysplastic syndrome (MDS), one with chronic myelomonocytic leukemia (CMML, MDS/MPN) and one with mixed phenotype acute leukemia (MPAL). Six patients had additional variants of undetermined significance (VUS) detected in ASXL1, CALR, EZH2, IDH2 and TET2. The other four patients had no additional variants identified by NGS but had cytogenetic abnormalities. One patient with MPAL had MECOM and IGH gene rearrangements detected on cytogenetic analysis. All patients had macrocytic anemia. One CMML patient with accompanying VUS in TET2 also had absolute monocytosis. BM cellularity and erythroid and granulocytic morphology were variable, ranging from unremarkable to left-shifted and dysplastic morphology. Nine (90%) cases showed atypical megakaryocyte morphology, characterized by hypolobated forms and osteoclast-like forms with separated and eccentrically located nuclear lobes. Interestingly, this megakaryocytic morphology was also observed in CCUS cases, albeit with lower frequency, below the 10% threshold necessary for the diagnosis of MDS. Megakaryocyte distribution was normal. Conclusions: Isolated LP/P ZSRS2 mutations are seen in a spectrum of myeloid neoplasms, including CCUS. They show a strong association with macrocytic anemia and megakaryocytic atypia/dysplasia. The presence of additional cytogenetic alterations and variants of undetermined significance is a confounding factor in determining the role of ZRSR2 mutations in driving the pathogenesis and morphologic features of these diseases.

Abstract Background Extramedullary disease (EMD) in multiple myeloma (MM) represents an aggressive phenotype with poor outcomes. We performed single-cell RNA sequencing (scRNA-seq) on clonal plasma cells (CPCs) from EMD tissue, solitary plasmacytomas (SPM), and bone marrow aspirates (BMAs) from patients with MM to identify transcriptional states unique to EMD. Methods We processed FFPE tumor samples from EMD and SPMs and cryopreserved CD138+ BMAs from MM, using the 10x Genomics FLEX platform. Cells/nuclei were fixed, hybridized with Human WTA probes, pooled, and sequenced (10,000–40,000 cells/library) on NovaSeq X. After removing low quality cells, data was normalized and integrated using RPCA in Seurat. Plasma cell identity was assigned via Cellarium and canonical markers. Clonality was inferred by light chain restrictions and refined via random forest modeling. Cell cycle effects were regressed out to reduce proliferation bias. Results We analyzed 128, 908 CPCs from 16 samples [8 EMD (62, 669 CPCs), 4 SPM (20, 607 CPCs), 4 BMA (45, 632 CPCs)] and identified eight transcriptionally distinct cell clusters. Differential expression and pathway comparisons were performed between EMD/SPM/BMA within each of these clusters. Integration of gene expression and pathway analyses revealed consistent upregulation of cell cycle and E2F pathways in EMD. We identified two highly proliferative cell cycle clusters (Cluster 2 with S-phase genes and Cluster 4 with a G2/M transcriptional program) that were expanded in EMD compared to BMA and SPM. Cluster 0 comprised a quiescent CPC population enriched for RNA processing pathways alongside downregulation of ER stress and autophagy. EMD cells demonstrated suppressed interleukin signaling [fold change (FC) –33.8), and class I MHC antigen processing (FC –23.5) relative to BMA, suggestive of an immune suppressive transcriptional program. Angiogenesis-related genes [VEGFA (log2FC 2.4), ADM2 (log2FC 2.2)] and EZH2 [log2FC 2.1; q<0.0001)] were upregulated in EMD. Compared to SPM, EMD plasma cells in this cluster demonstrated marked downregulation of CD74 (log2FC –2.6; q<0.0001), a key modulator of MHC class II antigen presentation. Cluster 1 comprised of metabolically stressed secretory CPCs and displayed downregulation of early growth response pathways in EMD compared to BMA, concurrent with upregulation of E2F signaling. Suppression of IL-2/STAT5, IL-6/JAK/STAT3, and TGF-β pathways in EMD suggests reduced reliance on bone marrow–derived cytokines and impaired immunoregulatory signaling. CD44 was upregulated in EMD versus BMA (log2FC 3.2), consistent with its role in EMD spread and marrow independence. Cluster 3 was enriched for extracellular matrix–interacting plasma cells (COL1A1, MMP2) with upregulated epithelial–mesenchymal transition (EMT) pathways in EMD compared to both BMA (FC 7.5) and SPM (FC 7.07). Cluster 6 was defined by a migratory, motility-primed plasma cell population (CD44, AHNAK, LMNA and S100A10). Notably, IL32 was overexpressed in EMD compared to BMA (log2FC 5.1; adj. p = 2.02×10⁻¹⁴), a finding linked to hypoxia-driven proliferation. Compared to SPM, EMD cells also had elevated MYC/E2F activity and DNA repair, hallmarks of a proliferative phenotype. Cluster 5 displayed a strong interferon-stimulated gene signature (ISG15, IFIT1, TNFSF10), with enrichment of type I IFN, JAK–STAT, and TNF pathways. Within this inflammatory cluster, EMD exhibited marked suppression of immune signaling, metabolism (TCA, OXPHOS), and TP53 programs, consistent with an immune-evasive, metabolically suppressed, and deregulated state. Finally, within Cluster 7, a smaller subset defined by NFκB–driven anti-apoptotic transcriptional activity, EMD exhibited significant downregulation of KLF2 (log2FC –3.7; adj. p = 1.77×10⁻²⁷), likely reflecting disruption of the KDM3A–KLF2–IRF4 axis, a transcriptional network critical for bone marrow homing and plasma cell survival. We consistently observed downregulation of the MAPK pathway in EMD compared to BMA, aligning with prior bulk RNA-seq data and contrasting with the near-universal presence of MAPK mutations, highlighting a disconnect between mutational status and pathway activation. Conclusion In the largest yet reported single-cell transcriptional atlas of EMD and SPM, we demonstrate EMD to be highly proliferative with metabolic reprogramming, EMT, and downregulation of key immunologic signaling pathways, indicating immune escape and microenvironmental independence.

Abstract Background Measurable residual disease (MRD) negativity post- autologous stem cell transplantation (ASCT) in newly diagnosed multiple myeloma (MM) is associated with favorable outcomes and may overcome the adverse impact of high-risk cytogenetic abnormalities (HRCAs). However, as the definition of high risk evolves and MRD emerges as a key endpoint, understanding its prognostic value within individual HRCAs is critical for treatment guidance. Methods We retrospectively included patients with NDMM that underwent an ASCT between September 19, 2016, and October 19, 2023, and achieved MRD negativity on Day 100 post ASCT. The MRD testing was conducted using multiparameter flow cytometry with a sensitivity of 2x10. HRCAs were defined as del(17p), 1q21+ gain or amplification (1q21+), t(4;14), t(14;16), t(14;20) and del(1p) and rest were considered standard risk (SRCA). Patients were grouped by the number of HRCAs (0, 1, ≥2). An adaptation of the recently proposed International Myeloma Society (IMS)/International Myeloma Working Group (IMWG) classification for high-risk disease (TP53 mutation unavailable) was also used. Progression-free survival (PFS), measured from stem-cell infusion to progression or death, was estimated using Kaplan–Meier methodology and compared using log-rank test. Results We identified 386 patients with MRD negativity post ASCT, of which 381 had cytogenetic data available for analysis. The median follow-up for the study cohort was 47.3 months (95% CI: 43.2-50). The median age at the time of ASCT was 65.7 (25.4-79.2) years and 58.3% patients were males. A total of 49% (n=189) patients had standard-risk cytogenetics, 31.4 % (n=121) harbored 1 HRCA, 15.3% (n=59) patients had two HRCAs and 3.1% (n=12) had 3 HRCAs. The individual HRCA by their prevalence were: 1q21+ in 35.5%(n=137), del(17p) in 14.3% (n=55), t(4;14) in 10.9% (n=42), t(14;16) in 5.4% (n=21), del(1p) in 4.2% (n=16), and t(14;20) in 1.04% (n=4) of patients. The most common double-hit lesions were1q21+ gain and/or amplification co-occurring with t(4;14) (33.9%, n=20) and del(17p) with 1q21+ (18.6%, n=11). Despite universal MRD negativity at Day 100, several HRCAs remained prognostically significant for PFS. Patients with del(17p) had worse 3-year PFS (71%) than those without (81%) [hazard ratio (HR)=1.85, 95% CI 1.11–3.07, p = 0.0172], though 3-year OS did not significantly differ at data cutoff (80% vs. 92%, p=0.1176). Presence of 1q21+ was associated with an inferior 3-year PFS (73%) compared to those without [84%, HR: 1.96 (95% CI: 1.25–3.06), p=0.0026], while 3-year OS was similar (88% vs. 91%, HR:1.33 p=0.36). Isolated 1q21+ had inferior PFS with comparable OS when compared to SRCA [3-year PFS of 82% vs. 88% respectively (HR:1.97, p=0.0177)]; 3-year OS was 91% vs. 94% (HR:1.38, p=0.44)]. Among 1q21+ patients, those with co-occurring HRCAs had a 3-year PFS of 66% vs. 81% for isolated 1q21+ (HR: 1.47, p=0.21). Patients with t(4;14) had worse 3-year PFS (64%) vs. 82% in non t(4;14) [HR 2.11(95% CI: 1.21-3.67) p=0.0064], and 3-year OS of 82% compared to 91% [HR 2.14 (95% CI: 1.02–4.49), p=0.038]. Isolated t(4;14) showed a 3-year PFS of 59% vs. 87% in standard-risk (p=0.06), and 3-year OS of 90% vs. 93% [HR 3.29, 95% CI 0.95–11.33, p = 0.06]. The presence of t(14;16), t(14;20), and del(1p) did not significantly affect 3-year PFS (all p>0.1), likely due to small subsets. When patients were grouped by the number of HRCAs, PFS declined with increasing cytogenetic complexity. Compared to standard risk, the 3-year PFS was 77% for 1 HRCA vs [HR = 2.11 (95% CI: 1.29–3.46), p = 0.0027], 67% for ≥2 HRCA [HR = 2.64 (95% CI: 1.53–4.57), p = 0.0005]. Maintenance therapy was used in 98% of patients. Patients with HRCAs received a doublet maintenance compared to SRCA (p<0.0001), even in MRD negative disease post ASCT. Conclusion In patients with certain HRCA, achievement of MRD negativity post-ASCT does not overcome the adverse impact of HRCA on PFS. In our cohort, patients with del(17p), t(4;14), or 1q21+ continued to exhibit significantly shorter PFS despite achieving MRD-negative status. These findings underscore the need for ongoing risk-adapted strategies even in patients with MM who attain MRD-negative state. The OS estimates are immature at this time.

Abstract Background Primary plasma cell leukemia (pPCL) is a rare and aggressive variant of multiple myeloma (MM), characterized by the presence of more than 5% circulating plasma cells on a peripheral blood smear. Despite advancements in therapy, including novel agents and autologous stem cell transplantation (ASCT), pPCL remains associated with markedly poorer survival outcomes compared to newly diagnosed MM. Although disease progression is common in pPCL, individual courses vary widely upon relapse and thereafter. We aim to describe the natural history of pPCL, focusing on clinical features and survival outcomes at the time of relapse or disease progression. Methods Patients with pPCL who were followed at our institution's cancer center between 2006-2024 were included for retrospective analysis. The electronic health record was reviewed to provide detailed information on patient demographics, disease characteristics, treatment regimens, and clinical outcomes. Time to next treatment (TTNT) and overall survival (OS) analysis were performed using the Kaplan-Meier method. Statistical analyses were performed using the SAS biostatistical software JMP 17.0.1 (SAS Institute Inc). Results We analyzed a cohort of 106 patients with relapsed pPCL after first-line therapy, all of whom received induction with novel agents. To date, 64 patients (60%) have died. Across the entire cohort, median OS is 39 months (mos) (95% CI: 25-68). 59 patients (56%) were diagnosed after 2015. Baseline FISH cytogenetics were available for 100 patients; 57 (57%) had one or more high-risk cytogenetic abnormality. Nearly all patients (96%) had ≥50% clonal plasma cells on initial bone marrow biopsy. While most patients (n = 61; 58%) were planned to undergo upfront ASCT, 20 (33%) experienced disease progression during induction therapy and required a more intensive salvage regimen (often infusional chemotherapy) prior to ASCT. The median TTNT after first-line therapy (TTNT#1) for the entire cohort was 10.4 mos (95% CI: 8–14). The median TTNT after second-line therapy (TTNT#2) for the entire cohort was 5.7 mos (95% CI: 4.3–7.1). Clinical details at first relapse, prompting initiation of second-line therapy, were available for 91 patients. Of these, 26 patients (29%) had symptomatic relapses—due to CRAB features or extramedullary disease—while 65 patients (71%) experienced asymptomatic biochemical progression. Symptomatic relapses were followed by significantly shorter TTNT#2 (3.9 vs. 7.0 mos; p = 0.039) and inferior OS from the start of second-line therapy (7.5 vs. 31.2 mos; p <0.0001) compared to asymptomatic relapses. The median TTNT#2 for patients who relapsed during induction and received salvage ASCT was 6.9 mos (n=20). In contrast, those treated after relapse with non-ASCT regimens (n = 86) fared worse; those receiving novel agent-based combinations, including doublets, triplets, or quadruplets (n=64) had respective median TTNT#2 of 3.3, 6.0, and 3.3 mos. Patients treated with infusional chemotherapy (n = 9) had the poorest outcomes, with a median TTNT#2 of just 1.4 mos. The median TTNT diminished with each subsequent line of therapy: TTNT#3 (n = 73) was 5.8 mos, TTNT#4 (n = 53) was 4.0 mos, and TTNT#5 (n = 35) was 2.6 mos. Patients with pPCL harboring the t(11;14) cytogenetic abnormality who were treated with venetoclax-based regimens (n = 8) during any line of therapy had a longer corresponding median TTNT of 15.0 mos. Additionally, 23 patients received anti-BCMA CAR-T cell therapy as a post-relapse line of therapy. At last follow-up, 15 of these patients (65%) had not relapsed, and after a median 20.7 mos of follow-up, the median TTNT following CAR-T cell therapy had not yet been reached. Patients who received CAR-T after 1-3 prior lines (n=15) had a median TTNT that was not reached; those who had received 4 or more prior lines (n=8) had a median TTNT of 20 mos. ConclusionsDespite the use of novel agent-based combination regimens and ASCT as first-line therapy, most patients with pPCL eventually experience disease progression. Consistent with MM, symptomatic relapse in pPCL is associated with poorer outcomes compared to asymptomatic biochemical progression. Additionally, the duration of response shortens with each successive line of therapy. Notable exceptions include venetoclax-based regimens in patients with t(11;14), and anti-BCMA CAR-T cell therapies: each appear to confer more durable responses than historical treatments in patients with relapsed pPCL.

Abstract Prognosis in acute myeloid leukemia (AML) patients is influenced by various factors, most importantly, patient clinical status and cytogenetic/molecular abnormalities. Within those factors, elevated lactate dehydrogenase (LDH) is considered a poor prognostic indicator in AML patients. Our study aims at exploring the different factors associated with elevated LDH and their impact on overall survival (OS). After obtaining IRB approval, we reviewed the charts of 381 AML patients diagnosed at Mayo Clinic, Rochester, between the years of 2016 and 2023. All data was recorded at the time of AML diagnosis. Patients with no cytogenetic and molecular data were excluded from this study. LDH levels were recorded if measured within 10 days of diagnosis and treatment for AML was not yet given. Both risk stratification and response evaluation were done following the 2022 European LeukemiaNet (ELN) guidelines. OS was calculated from the date of AML diagnosis to the date of last follow-up or death. We used BlueSky Statistics V 10.3.4 for statistical analysis. We identified 299 patients (78.4%) who had elevated LDH levels (normal ≤ 222 U/L) at the time of diagnosis with a median of 417 U/L (range, 223-7989). The median age for those patients was 68 years (range, 18-94), with 78 (26.1%) of them having a prior myeloid disease (MDS, MPN, or MDS/MPN) before AML diagnosis. By risk stratification, more than half of the patients had an adverse risk profile (n=171, 57.2%), while 71 (23.7%) and 57 (19.1%) had an intermediate and favorable risk, respectively. Most of those patients had an abnormal karyotype (n=204, 68.7%), with complex karyotype (n=103, 34.7%) being the most common abnormality, followed by monosomy 7 (n=50, 16.8%) and trisomy 8 (n=46, 15.5%). Next-generation sequencing (NGS) was performed on 268 (89.6%) patients with elevated LDH, and the most common mutations were TP53 (n=60, 22.3%), FLT3-ITD (n=59, 21.1%), and NPM1 (n=51, 18.5%). TP53 mutations were more common in patients with normal/low white blood cell count (WBC) in contrast with FLT3 and NPM1, which were the most common mutations in patients with high WBC. After grouping the patients according to their LDH levels (group 1: 223-444 U/L, group 2: 444-666 U/L, group 3: > 666 U/L), we found that FLT3-ITD mutations were more likely to occur at higher LDH levels i.e. groups 2 and 3 (p= 0.002). The majority of patients with elevated LDH (n=262, 87.6%) received therapy following diagnosis, with the most common treatment regimens being a combination of a hypomethylating agent and venetoclax (HMA+VEN) (n=97, 37%) and a (7+3)-based induction therapy (n=77, 29.4%). When comparing patients with elevated LDH (n=299, 78.4%) to patients who had non-elevated LDH (n=82, 21.5%), no difference in both median age at diagnosis and risk stratification was found. We noticed an increase in WBC (median, 7.7 vs. 2.1) (p<0.001) along with an increase in peripheral blasts (median, 28% vs. 7%) (p<0.001) in elevated LDH patients. Among patients with non-elevated LDH, 21% (n=17) had a complex karyotype compared to 34.7% (n=103) in the elevated LDH group (p=0.022). The molecular profile was different between the 2 groups, where the most common mutations in patients with non-elevated LDH were IDH2 (n=19, 25.3%), RUNX1 (n=17, 23%), and DNMT3A (n=16, 21.6%). All patients (n=82, 100%) in the non-elevated LDH group received therapy after diagnosis. There was no difference in terms of treatment regimens used between the 2 groups. Moreover, no statistical difference in remission rates after one line of therapy was found between those groups where non-elevated LDH patients had a 65.9% remission rate compared to the 55.3% remission rate in patients with elevated LDH (p=0.098). Patients with elevated LDH had a shorter OS than patients with non-elevated LDH (9.5 vs. 26.4 months, p=0.0008). However, median OS was similar across the different groups of elevated LDH. Using univariate analysis in our cohort (n=381), age, HSCT, risk stratification, FLT3 mutation, and LDH elevation all had an impact on OS. However, when comparing those variables using multivariate analysis, age and FLT3 mutation lost their significance (p-value of 0.25 and 0.84, respectively).Complex karyotype and FLT3 mutations were more common in patients with elevated LDH. These patients tend to have higher WBC and peripheral blasts. Elevated LDH had a negative impact on patients' OS regardless of patients' risk classification.

ABSTRACT Light chain multiple myeloma (LCMM) is a subtype of multiple myeloma (MM) characterized by the exclusive production of immunoglobulin light chains and accounts for 15%–20% of newly diagnosed MM. A comprehensive comparison of LCMM with MM producing intact immunoglobulin (non‐LCMM) remains limited. In this retrospective study, we described distinct clinical and cytogenetic features and assessed long‐term outcomes in 852 LCMM patients diagnosed between 01/01/2004 and 12/31/2022, compared with non‐LCMM controls matched for age, sex, and year of diagnosis. On univariable analysis, LCMM patients were more likely to present with elevated creatinine (> 2 mg/dL), beta‐2‐microglobulin ≥ 5.5 mg/L, elevated LDH, hypercalcemia, t(11;14), del(13q), and t(6;14). Conversely, IMS‐IMWG high‐risk disease, hyperdiploidy, t(4;14), and serum albumin < 3.5 g/dL were less common. On multivariable analysis, elevated creatinine (OR: 5.1, 95% CI: 1.2–27, p = 0.04), t(11;14) (OR: 2.6, 95% CI: 1.3–5.2, p = 0.006), and del(13q) (OR: 4.1, 95% CI: 2.1–8.2, p < 0.001) were independently associated with LCMM, while IMS‐IMWG high‐risk disease (OR: 0.3, 95% CI: 0.1–0.8, p = 0.02) and hyperdiploidy (OR: 0.3, 95% CI: 0.1–0.7, p = 0.002) were less frequent. Despite these differences, progression‐free survival with frontline treatment (HR: 0.97, 95% CI: 0.84–1.11, p = 0.63) and overall survival (HR: 0.99, 95% CI: 0.87–1.13, p = 0.94) were similar between LCMM and non‐LCMM patients. This study highlights the distinct clinical and cytogenetic features of LCMM, marked by higher rates of renal failure, t(11;14), and del(13q), lower prevalence of IMS‐IMWG high‐risk disease, and comparable survival outcomes.

Evaluation of T-cell receptor (TCR) β-chain constant region 1 (TRBC1) expression is an alternative T-cell clonality assessment method. However, evaluation of TRBC1 immunohistochemistry (IHC) for distinguishing mycosis fungoides (MF)/Sezary syndrome (SS) from reactive inflammatory infiltrates in skin is incomplete. We evaluated the utility of a novel dual TRBC1-CD3 IHC stain in skin biopsies with MF/SS (n=40), reactive (n=24), or atypical T-cell infiltrates indeterminant for MF/SS (n=9). Twenty of 24 reactive cases showed clear polytypic TRBC1 expression (median percent TRBC1 positivity among CD3-positive T cells [%TRBC1+] 50% in dermis, 42.5% in epidermis among all cases), while 34/40 MF/SS were clearly monotypic (%TRBC1+ either ≤20% or ≥85%) (sensitivity 85.0%, specificity 91.7%, positive predictive value 94.4%, negative predictive value 78.6%). Discordance between TRBC1 expression and diagnosis was associated with few neoplastic/monotypic T cells and/or lack of physical separation between neoplastic and non-neoplastic populations. Among patch/plaque MF/SS, TRBC1 showed similar diagnostic sensitivity (80.0% vs. 86.7%) and high categorical correlation (monotypic vs. not monotypic, 80%) with TCR gene rearrangement results. TRBC1 interpretation was reproducible, with ≥2/3 and 3/3 pathologists rendering identical interpretations in 100% and 86% of cases, respectively, after independent review and 100% agreement following collective review. Digital image analysis confirmed visual %TRBC1+ accuracy ( r =0.9749, P <0.0001). On the basis of these results, we propose %TRBC1+ cutoffs of <25% or >75% for establishing T-cell monotypia in skin. Considering such thresholds, TRBC1-CD3 evaluation facilitated diagnostic refinement in 7/9 (78%) atypical cases. Overall, TRBC1-CD3 IHC clearly and rapidly aids diagnosis of cutaneous T-cell proliferations.