A surrogate molecular approach for the detection of Philadelphia chromosome–like B‐acute lymphoblastic leukemia.

Background: Philadelphia chromosome (Ph)–like B‐acute lymphoblastic leukemia (B‐ALL) is a clinically significant, high‐risk genetic subtype of B‐ALL cases. There are few data on the incidence, characterization, and treatment outcomes of Ph‐like ALL cases from low‐ and middle‐income countries. There is a pressing need to establish a well‐organized/cost‐effective approach for identifying Ph‐like ALL instances. Methods: Multiplex reverse transcriptase polymerase chain reaction, nCounter NanoString, and fluorescence in situ hybridization were used to detect and characterize Ph‐like ALL cases among recurrent genetic abnormalities (RGA)neg B‐ALL cases. At the end of induction therapy, flow cytometry‐minimal residual disease (MRD) assay was used to quantify MRD positivity in Ph‐like ALL cases. Results: Of 130 newly diagnosed B‐ALL cases, 25% (BCR::ABL1), 4% (ETV6::RUNX1), 5% (TCF3::PBX1), 2% (KM2TA::AFF1), and 65% RGAneg B‐ALL cases were revealed by multiplex reverse transcriptase polymerase chain reaction. Among RGAneg B‐ALL cases, 24% Ph‐like ALL cases using nCounter NanoString were identified, with 48% CRLF2high cases with 45% CRLF2::P2RY8 and 18% CRLF2::IGH rearrangements(∼r) revealed by fluorescence in situ hybridization. In 52% of CRLF2low cases, 17% ABL1 and JAK2∼r 8% EPOR::IGH & PDGRFB∼r were identified. Ph‐like ALL cases had higher total leukocyte count (p <.05), male preponderance (p <.05), and high MRD‐positivity/induction failure compared with RGAneg B‐ALL cases. Furthermore, in Ph‐like ALL cases, 11 significant genes using quantitative polymerase chain reaction were identified and validated. CRLF2, IGJ, CEACAM6, MUC4, SPATS2L and NRXN3 genes were overexpressed and show statistical significance (p <.05) in Ph‐like ALL cases. Conclusions: This study showed the high incidence of Ph‐like ALL cases with kinase activating alterations and treatment outcomes from low‐ and middle‐income region. Furthermore, a surrogate cost‐effective multiplex panel of 11 overexpressed genes for the prompt detection of Ph‐like ALL cases is proposed. Plain Language Summary: Identification of recurrent gene abnormalities (RGA)neg B‐acute lymphoblastic leukemia (B‐ALL) cases using multiplex‐reverse transcriptase polymerase chain reaction.Identification and characterization of Philadelphia (Ph)–like ALL cases using nCounter NanoString gene expression profiling and fluorescence in situ hybridization.Furthermore, Ph‐like ALL cases were characterized according to CRLF2 expression and kinase‐activating genomic alterations. Minimal residual disease of Ph‐like ALL cases were quantified using flow cytometry‐minimal residual disease assay.A surrogate molecular approach was established to detect Ph‐like ALL cases from low‐ and middle‐income countries. A surrogate approach for the rapid baseline detection of Philadelphia chromosome (Ph)–like acute lymphoblastic leukemia cases, followed by its kinase gene alterations. Early detection of Ph–like acute lymphoblastic leukemia cases is extremely important to start personalized treatments to improve the overall survival/outcomes of these cases. [ABSTRACT FROM AUTHOR]