Precision medicine in AML: Function plus -omics is better than either alone

How I treat AML relapse after allogeneic HSCT

ABSTRACT

Allogeneic hematopoietic stem cell transplantation (HSCT) is one of the principal curative approaches in the treatment of acute myeloid leukemia (AML); however, relapse after transplantation remains a catastrophic event with poor prognosis. The incidence of relapse has remained unchanged over the last 3 decades despite an evolving understanding of the immunobiology of the graft-versus-leukemia effect and the immune escape mechanisms that lead to post-HSCT relapse. The approach to posttransplant relapse is highly individualized and is dictated both by disease biology and genomics as well as the patient's clinical status at the time of relapse and the interval between relapse and transplantation. With the help of 3 illustrative cases, we discuss our approach to early, late, and incipient relapse. Current therapeutic strategies incorporate immunosuppression taper when feasible, a variety of targeted and nontargeted chemotherapeutic agents, and consolidative cellular therapies including donor lymphocyte infusions or a second allogeneic transplant. We then summarize evolving frontiers in the treatment and prognostication of relapse, including the critical role of measurable residual disease. Finally, we emphasize enrollment on clinical trials and thoughtful discussions regarding goals of care and supporting frail patients as universal principles that should be incorporated in approaches to treatment of AML relapse after transplantation.

Comparing functional and genomic-based precision medicine in blood cancer patients

Tumor-agnostic precision medicine (PM) strategies promise to support treatment decisions in relapsed/refractory blood cancer patients. Genomic-based PM (gPM) and drug screening-based functional PM (fPM) currently represent the most prominent PM methodologies. In this study, we report the feasibility analysis of the first 55 patients enrolled in the multicentric, randomized controlled EXALT-2 trial (NCT04470947) comparing treatment recommendations of gPM, fPM, and physicians' choice (PC) head to head. In 54 patients (98%), the diagnostic workflow was successfully implemented, resulting in treatment recommendations for 42 patients (76%), of whom 29 (69%) received the suggested individualized treatments. Actionable targets were identified in 65% by gPM and 80% by fPM (64% microscopy-based, 86% flow cytometry-based fPM). The median time to report was shorter for fPM than for gPM testing. The two strategies revealed overlapping drug targets in 60% of cases. Both, gPM and fPM can efficiently be integrated into the clinical routine to guide therapy decisions for the majority of patients.

Integrated analysis and validation reveal CYTH4 as a potential prognostic biomarker in acute myeloid leukemia

Acute myeloid leukemia (AML) is a clonal hematological malignancy with high mortality rates. The identification of novel markers is urgent for AML. Cytohesins are a subfamily of guanine nucleotide exchange factors activating the ADP-ribosylation factor family GTPases. While the important roles of cytohesins have been reported in various cancers, their function in AML remains unclear. The present study aimed to explore the prognostic impact of cytohesin-4 (CYTH4) and the underlying molecular functions. RNA sequencing and AML clinical data were obtained from The Cancer Genome Atlas and Gene Expression Omnibus databases to investigate gene expression and survival. Using the R software, differentially expressed genes were identified between the high- and the low-CYTH4 group. Functional enrichment analysis was conducted by Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, and Gene Set Enrichment Analyses. The CIBERSORTx tool was used to explore the proportions of different immune cell types. The molecular function of CYTH4 was also validated in vitro by examining cell growth, cell cycle, apoptosis and colony-forming ability. CYTH4 was significantly upregulated in AML compared with other cancers and normal tissues. High CYTH4 expression was associated with high white blood count (P=0.004) and higher risk status (P<0.001). Patients with high CYTH4 expression had poor overall survival (OS; HR=2.19; 95% CI, 1.40-3.44; P=0.0006; high vs. low) and event-free survival (EFS; HR=2.32; 95% CI, 1.43-3.75; P=0.0006; high vs. low), and these patients could benefit from transplantation (HR=0.29; 95% CI, 0.18-0.47; P<0.0001; transplantation vs. chemotherapy). Multivariate analysis showed that high CYTH4 expression was independently associated with inferior OS (HR=2.49; 95% CI, 1.28-4.83; P=0.007) and EFS (HR=2.56; 95% CI, 1.48-4.42; P=0.001). Functional analysis showed that CYTH4 was involved in immunoregulation. In vitro validation showed knockdown of CYTH4 adversely affected cell growth and induced cell apoptosis, while overexpression of CYTH4 enhanced cell growth. Taken together, CYTH4 is expressed at high levels in AML and can potentially function as a prognostic biomarker.