Citations

Abstract Lineage switch (LS), defined as the immunophenotypic transformation of acute leukemia, has emerged as a mechanism of relapse after antigen-targeted immunotherapy, which is associated with dismal outcomes. Through an international collaborative effort, we identified cases of LS after a host of antigen-targeted therapies (eg, CD19, CD22, CD38, and CD7), described how LS was diagnosed, reviewed treatment approaches, and analyzed overall outcomes for this form of postimmunotherapy relapse. Collectively, 75 cases of LS were evaluated, including 53 (70.7%) cases of B-cell acute lymphoblastic leukemia (B-ALL) transforming to acute myeloid leukemia (AML), 17 (22.7%) cases of B-ALL transforming to mixed phenotypic acute leukemia (MPAL)/acute leukemias of ambiguous lineage (ALAL), and 5 (6.7%) cases of rare LS presentation (ie, T-cell ALL to AML). An additional 10 cases with incomplete changes in immunophenotype, referred to as “lineage drift” were also described. With a primary focus on the 70 cases of LS from B-ALL to AML or MPAL/ALAL, LS emerged at a median of 1.5 months (range, 0-36.5) after immunotherapy, with 81.4% presenting with LS within the first 6 months from the most proximal immunotherapy. Although most involved KMT2A rearrangements (n = 45, 64.3%), other rare cytogenetic and/or molecular alterations were uniquely observed. Treatment outcomes were generally poor, with remission rates of <40%. The median overall survival after LS diagnosis was 4.8 months. Outcomes were similarly poor for those with rare immunophenotypes of LS or lineage drift. This global initiative robustly categorizes lineage changes after immunotherapy and, through enhanced understanding, establishes a foundation for improving outcomes of LS.

AbstractWith increasing opportunities for minors to undergo genomic testing, factors influencing young people's decision stability and instability regarding genomic testing are unclear. This interpretive description study examines decision stability when adolescents (13–17) and young adults (18–21) decide whether to learn genetic testing results. Adolescents and young adults enrolled in a clinical trial chose whether they wanted to learn genetic testing results and could modify their decisions during a study visit or 2 weeks later. A purposive sample of clinical trial participants was invited to participate in an interview exploring their decision preferences, confidence level, and factors impacting decision stability. Twenty‐two participants chose to learn all (n = 7), some (n = 7), or no genetic test results (n = 8). Perceptions of the impact of personal genetic information on one's quality of life and sense of reproductive goals and responsibilities were driving factors for people who chose to learn no or some genetic results, while curiosity influenced those who chose to learn all. Prior health and healthcare experiences and others' influence also factored into decision‐making about receiving results. Decision stability varied among individuals but increased over time and was positively influenced by parents, baseline decision confidence, and fear of missing out on the opportunity to learn genetic information. Participants felt favorably about the opportunity to change their decision 2 weeks after the study visit. Among study participants, decision stability was high, as was satisfaction with decisions regarding how much personal genetic information to learn. The results suggest that adolescent and young adult genetic research participants may experience high decision stability and confidence in making choices regarding personal genetic testing, especially when a window of opportunity for change is available. Researchers and clinicians should consider the benefits and challenges of offering multiple checkpoints to bolster decision stability.

Using 32 immune cell surface markers, we identified 23 monocyte clusters in murine blood. Diabetic gastroparesis was associated with a significant decrease in two circulating classical monocyte-like clusters and an upregulation of the Ccr2-Ccl2 axis in the gastric muscularis propria, suggesting increased tissue monocyte migration. This study offers new targets by pointing to a possible role for two classical monocyte subsets connected to the Ccr2- Ccl2 axis.

Context.— A monthly pathology journal club has met for 24 years. It was established to help members stay apprised of the literature relevant to diagnostic pulmonary pathology. Objective.— To assess whether the journal club met its goal and to report on opportunities identified for improvement. Design.— To determine whether articles chosen for discussion as opposed to notation were more significant, Scopus citation indices for article types reviewed from January 2007 to November 2023 were compared. A survey of current faculty was undertaken to determine if the club was meeting expectations and to identify improvement opportunities. Results.— Articles from January 2007 to November 2023 included 858 discussed and 3385 noted. Mean (SD) citation count was 103.0 (409.80) for discussion and 64.9 (259.77) for notation articles ( P < .001). The citation count was noticeably right skewed, as articles with high citation counts inflated the mean. Members were mostly satisfied with the way the journal club was structured and managed. Members most valued the summary of the articles, followed by the live discussion. Opportunities for improvement included decreasing the number of journals scanned, decreasing detail in summaries, and using generative artificial intelligence (AI) to facilitate summary generation. A pilot using AI anecdotally reduced preparatory time, but the human-edited summary included more specific context, critical commentary, and enhanced take-home messages, providing a more nuanced analysis. Conclusions.— The journal club met its initial goal. Opportunities for improvement have been identified including the use of generative AI to facilitate article summarization.

Abstract Background: ASXL1 is one of the three most frequently mutated genes in age-related clonal hematopoiesis (CH), with the others being DNMT3A and TET2. CH frequently progresses to myeloid malignancies including chronic monomyelocytic leukemia (CMML), and is also strongly associated with inflammatory cardiovascular disease and all-cause mortality in humans. DNMT3A and TET2 regulate DNA methylation and demethylation pathways respectively, and loss-of-function mutations of both genes reduce DNA methylation in heterochromatin. In contrast, the mechanisms that connect mutant ASXL1 and CH are not yet fully understood. ASXL1 is a regulatory component of the ASXL1-BAP1 deubiquitinase complex, which removes ubiquitin from mono-ubiquitinated H2A lysine 119 (H2AK119Ub). Recurrent frameshift and nonsense ASXL1 mutations in CH and CMML generate C-terminally truncated proteins that improve BAP1 enzymatic activity. Methods: To relate ASXL1 mutations to CH, we performed the protein immunoprecipitation followed by a mass spectrum to identify proteins interacting with mutant ASXL1. Utilizing a heterozygous Asxl1 mutant knock-in mouse model to recapitulate ASXL1-driven clonal hematopoiesis, we characterized alterations in histone modifications within expanded myeloid populations using CUT&RUN, with Drosophila S2 cells as spike-ins for normalization. Differential gene expression and transposable elements (TEs) activity were quantified in ASXL1-mutant chronic myelomonocytic leukemia (CMML) patients using RNA sequencing (RNA-seq) to assess the broader impact of ASXL1 mutations on transcriptional regulation. Results: Here we show that ASXL1 mutant proteins interact with the EHMT1-EHMT2 methyltransferase complex, which generates H3K9me1 and me2, the latter a repressive modification in constitutive heterochromatin. Compared to cells from age-matched wildtype mice, we found that expanded myeloid cells from old Asxl1 mutant mice display genome-wide decreases of H3K9me2, H3K9me3 and H2AK119Ub as well as an associated increase in expression of transposable elements (TEs) and satellite repeats. Increased TE expression was also observed in monocytes from ASXL1-mutant CMML patients compared to monocytes from healthy controls. Our data suggest that mutant ASXL1 proteins compromise the integrity of both constitutive and facultative heterochromatin in an age-dependent manner, by reducing the levels of H3K9me2/3 and H2AK119Ub. This increase in TE expression correlated with increased expression of nearby genes, including many interferon-inducible (inflammation-associated) genes (ISGs). Conclusion: Our findings provide new insights into how ASXL1 gain-of-function mutations might contribute mechanistically to the progression of CH and myeloid malignancies in aging. We show that even heterozygous expression of truncated ASXL1 proteins can lead to reduced levels of heterochromatin-associated histone modifications, weakening heterochromatin integrity and promoting increased expression of transposable elements that are normally silenced in heterochromatin. Citation Format: Zhen Dong, Hugo Sepulveda, Leo Josue Arteaga Vazquez, Mrinal Patnaik, Samuel A Myers, Anjana Rao. A mutant ASXL1-EHMT complex contributes to heterochromatin dysfunction in clonal hematopoiesis and chronic monomyelocytic leukemia [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: DNA Methylation, Clonal Hematopoiesis, and Cancer; 2025 Feb 1-4; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2025;85(3 Suppl):Abstract nr B001.

131 Background: KRAS G12C mutations occur in 3%–4% of CRC cases and are associated with poor prognosis. In the phase 1/2 KRYSTAL-1 study (NCT03785249), at a median follow-up of 11.9 months (mo), Ada (irreversible inhibitor of KRAS G12C ) in combination with Cetux (anti-EGFR antibody) demonstrated promising clinical activity (objective response rate [ORR] of 34% per blinded independent central review [BICR] and 43% per investigator [INV]) and was well tolerated in patients (pts) with previously treated KRAS G12C -mutated mCRC. Based on these findings, Ada + Cetux was granted accelerated approval in the United States for these pts. Here, we present longer-term follow-up analyses from this study. Methods: Adults with previously treated KRAS G12C -mutated mCRC and ECOG performance status of 0 or 1 were treated with Ada (600 mg BID) in combination with Cetux (400 mg/m 2 followed by 250 mg/m 2 QW or 500 mg/m 2 Q2W) until disease progression, unacceptable toxicity, withdrawal of consent, or death, in separate phase 1 and phase 2 cohorts. Primary endpoints were safety (phase 1) and ORR per BICR (phase 2). Secondary endpoints were duration of response (DOR), progression-free survival (PFS), overall survival (OS), and safety (phase 2). Results: A total of 94 pts received Ada + Cetux. The median number of prior lines of systemic therapy was 3 (range, 1–9); 23 pts (24%) had received ≥ 4 prior lines of systemic therapy. The most frequent sites of metastases at baseline were the lung (71%) and liver (64%). At a median follow-up of 20.4 mo, ORR per INV was 43% (95% CI 32–53) and all were partial responses; median DOR was 5.9 (95% CI 5.5–7.6) mo. Disease control rate per INV was 86% (95% CI 78–92). Median PFS per INV was 6.9 (95% CI 5.9–7.4) mo; 6- and 12-mo PFS rates were 61% and 19%, respectively. Median OS was 16.0 (95% CI 13.3–18.8) mo; 6- and 12-mo OS rates were 88% and 66%, respectively. Any-grade treatment-related adverse events (TRAEs) were reported in 100% of pts, 28% of which were grade 3/4. TRAEs led to discontinuation in 10% of pts. Efficacy analyses by BICR, subgroup analyses, and additional safety results will be presented. Conclusions: In heavily pretreated pts with KRAS G12C -mutated mCRC, Ada + Cetux continued to demonstrate clinically meaningful activity and tolerable safety with longer follow-up. These updated results are consistent with those from the primary analysis and constitute the longest duration of follow-up for dual KRAS G12C /EGFR blockade in this setting. Efficacy of second-line Ada + Cetux vs chemotherapy in KRAS G12C -mutated mCRC is being investigated in the phase 3 KRYSTAL-10 study (NCT04793958). Clinical trial information: NCT03785249 .

INTRODUCTION: Patients with ulcerative colitis (UC) and prior biologic failure may have reduced or delayed efficacy with subsequent advanced therapies. This analysis evaluated the efficacy and safety of ozanimod during the True North (TN) study and its open-label extension (OLE) in biologic-exposed patients with UC. METHODS: TN was a randomized, placebo-controlled 52-week trial (10-week induction, 42-week maintenance period). Eligible patients could enter the OLE. Clinical outcomes were assessed at TN week (W) 10 and W52 and OLE W46 and W94. Symptomatic efficacy was evaluated through induction and in the OLE until W94. Safety was assessed. RESULTS: This analysis included 376 biologic-exposed patients. In the placebo-controlled cohort, more ozanimod-treated patients achieved clinical response than placebo at W10 regardless of the number or type of prior biologics; patients who used 1 vs ≥2 prior biologics achieved higher efficacy rates. Efficacy rates were higher at W52 than W10 and were similar across subgroups regardless of the number or type of prior biologics. Significantly greater proportions of ozanimod vs placebo patients achieved symptomatic response by W5 ( P = 0.0173) and symptomatic remission by W10 ( P = 0.0207). Among biologic-exposed TN W10 ozanimod nonresponders who entered the OLE, 61% achieved symptomatic response with an extra 10 weeks of ozanimod treatment. Ozanimod efficacy was durable for ∼3 years of continuous treatment in biologic-exposed W52 clinical responders who entered the OLE. No new safety signals were observed. DISCUSSION: Ozanimod was effective and safe in biologic-exposed patients with UC, but these patients may require more time to respond to treatment. Clinical trial registry website and trial numbers: ClinicalTrials.gov, numbers NCT02435992 and NCT02531126.

ASXL transcriptional regulator 1 (ASXL1) is one of the three most frequently mutated genes in age-related clonal hematopoiesis (CH), alongside DNA methyltransferase 3 alpha (DNMT3A) and Tet methylcytosine dioxygenase 2 ( TET2) . CH can progress to myeloid malignancies including chronic monomyelocytic leukemia (CMML) and is also strongly associated with inflammatory cardiovascular disease and all-cause mortality in humans. DNMT3A and TET2 regulate DNA methylation and demethylation pathways, respectively, and loss-of-function mutations in these genes reduce DNA methylation in heterochromatin, allowing derepression of silenced elements in heterochromatin. In contrast, the mechanisms that connect mutant ASXL1 and CH are not yet fully understood. CH/CMML-associated ASXL1 mutations encode C-terminally truncated proteins that enhance the deubiquitinase activity of the ASXL-BAP1 “PR-DUB” deubiquitinase complex, which removes monoubiquitin from H2AK119Ub. Here, we show that ASXL1 mutant proteins interact with the euchromatic histone lysine methyltransferases 1 and 2 (EHMT1–EHMT2) complex, which generates H3K9me1 and me2, the latter a repressive modification in constitutive heterochromatin. Compared to cells from age-matched wild-type mice, we found that expanded myeloid cells from old (≥18-mo-old) Asxl1tm/+ mice, a heterozygous knock-in mouse model of CH, display genome-wide decreases of H3K9me2, H3K9me3, and H2AK119Ub as well as an associated increase in expression of transposable elements (TEs) and satellite repeats. Increased TE expression was also observed in monocytes from ASXL1 -mutant CMML patients compared to monocytes from healthy controls. Our data suggest that mutant ASXL1 proteins compromise the integrity of both constitutive and facultative heterochromatin in an age-dependent manner by reducing the levels of H3K9me2/3 and H2AK119Ub. This increase in TE expression correlated with increased expression of nearby genes, including many interferon-inducible (inflammation-associated) genes (ISGs).