RESUMEN
There has been a controversy about the predictive value of tissue-TMB-H for immune checkpoint inhibitors (ICIs) with limited data regarding blood-TMB (bTMB) in GI tumors. We aim to evaluate the predictive value of bTMB compared with MSI-H in GI tumors. Patients with unresectable/metastatic GI cancer, harboring either MSS with bTMB-H (≥10 mut/Mb) or dMMR/MSI-H who received ICI were included. We compared ICIs' efficacy between MSS-bTMB-H (N=45) versus MSI-H (N=50) in GI tumors. Ninety-five patients were identified with the majority having colorectal (49.5%) or esophagogastric (34.7%) cancers. MSS-bTMB-H group had more esophagogastric cancer and later-line ICI recipients, with no significant differences in other known prognostic variables. At a median follow-up of 9.4 months, MSI-H group showed superior ORR (58.0% vs. 26.7%), DCR (84.0% vs. 42.2%), DoR (not-reached vs. 7.6 mo), PFS (22.5 vs. 3.8 mo), and OS (Not-reached vs. 10.1 mo) compared with MSS-bTMB-H. Multivariable analysis showed that MSI-H was an independent favorable factor over MSS-bTMB-H for PFS (HR=0.31, CI 0.15-0.63, P=0.001) and OS (HR=0.33, CI 0.14-0.80, P=0.014). MSI-H group showed favorable outcomes compared with MSS-bTMB-16+ (ORR: 58.0% vs. 26.9%; DCR: 84.0% vs. 42.3%; PFS:22.5 vs. 4.0 mo) and MSS-bTMB-20+ (ORR: 58.0% vs. 31.6%; DCR: 84.0% vs. 42.1%; PFS:22.5 vs. 3.2 mo). There was no difference between MSS-bTMB10-15 compared with MSS-bTMB-16+ in ORR, DCR, and PFS, or between MSS-bTMB10-19 compared with MSS-bTMB20+. Regardless of bTMB cutoff at 10, 16, or 20, bTMB-H did not appear to be a predictive biomarker in MSS GI tumors in this retrospective analysis.
RESUMEN
Myeloid neoplasms arise from preexisting clonal hematopoiesis (CH); however, the role of CH in the pathogenesis of acute lymphoblastic leukemia (ALL) is unknown. We found that 18% of adult ALL cases harbored TP53, and 16% had myeloid CH-associated gene mutations. ALL with myeloid mutations (MyM) had distinct genetic and clinical characteristics, associated with inferior survival. By using single-cell proteogenomic analysis, we demonstrated that myeloid mutations were present years before the diagnosis of ALL, and a subset of these clones expanded over time to manifest as dominant clones in ALL. Single-cell RNA sequencing revealed upregulation of genes associated with cell survival and resistance to apoptosis in B-ALL with MyM, which responds better to newer immunotherapeutic approaches. These findings define ALL with MyM as a high-risk disease that can arise from antecedent CH and offer new mechanistic insights to develop better therapeutic and preventative strategies. SIGNIFICANCE: CH is a precursor lesion for lymphoblastic leukemogenesis. ALL with MyM has distinct genetic and clinical characteristics, associated with adverse survival outcomes after chemotherapy. CH can precede ALL years before diagnosis, and ALL with MyM is enriched with activated T cells that respond to immunotherapies such as blinatumomab. See related commentary by Iacobucci, p. 142.
