Abstract CT077: Potential utility of minimal residual disease (MRD) to identify relapse in pediatric and young adult (AYA) B-cell acute lymphoblastic leukemia (B-ALL) patients treated with tisagenlecleucel

Author(s):  
Michael A. Pulsipher ◽  
Xia Han ◽  
Máire Quigley ◽  
Gabor Kari ◽  
Susana Rives ◽  
...  
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Stephanie L. Rellick ◽  
Gangqing Hu ◽  
Debra Piktel ◽  
Karen H. Martin ◽  
Werner J. Geldenhuys ◽  
...  

AbstractB-cell acute lymphoblastic leukemia (ALL) is characterized by accumulation of immature hematopoietic cells in the bone marrow, a well-established sanctuary site for leukemic cell survival during treatment. While standard of care treatment results in remission in most patients, a small population of patients will relapse, due to the presence of minimal residual disease (MRD) consisting of dormant, chemotherapy-resistant tumor cells. To interrogate this clinically relevant population of treatment refractory cells, we developed an in vitro cell model in which human ALL cells are grown in co-culture with human derived bone marrow stromal cells or osteoblasts. Within this co-culture, tumor cells are found in suspension, lightly attached to the top of the adherent cells, or buried under the adherent cells in a population that is phase dim (PD) by light microscopy. PD cells are dormant and chemotherapy-resistant, consistent with the population of cells that underlies MRD. In the current study, we characterized the transcriptional signature of PD cells by RNA-Seq, and these data were compared to a published expression data set derived from human MRD B-cell ALL patients. Our comparative analyses revealed that the PD cell population is markedly similar to the MRD expression patterns from the primary cells isolated from patients. We further identified genes and key signaling pathways that are common between the PD tumor cells from co-culture and patient derived MRD cells as potential therapeutic targets for future studies.


Blood ◽  
2010 ◽  
Vol 115 (18) ◽  
pp. 3763-3771 ◽  
Author(s):  
Peter Rhein ◽  
Rita Mitlohner ◽  
Giuseppe Basso ◽  
Giuseppe Gaipa ◽  
Michael N. Dworzak ◽  
...  

Abstract A consistently increased mRNA expression of the adhesion receptor CD11b is a hallmark of the reported genomewide gene expression changes in precursor B-cell acute lymphoblastic leukemia (PBC-ALL) after 1 week of induction therapy. To investigate its clinical relevance, CD11b protein expression in leukemic blasts has been prospectively measured at diagnosis (159 patients) and during therapy (53 patients). The initially heterogeneous expression of CD11b inversely correlated with cytoreduction rates measured at clinically significant time points of induction therapy in the ALL–Berlin-Frankfurt-Münster 2000 protocol. CD11b positivity conferred a 5-fold increased risk of minimal residual disease (MRD) after induction therapy (day 33) and of high-risk group assignment after consolidation therapy (day 78). In the multivariate analysis CD11b expression was an independent prognostic factor compared with other clinically relevant parameters at diagnosis. During therapy, CD11b expression increased early in most ALL cases and remained consistently increased during induction/consolidation therapy. In more than 30% of MRD-positive cases, the CD11b expression on blast cells exceeded that of mature memory B cells and improved the discrimination of residual leukemic cells from regenerating bone marrow. Taken together, CD11b expression has considerable implications for prognosis, treatment response monitoring, and MRD detection in childhood PBC-ALL.


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