In P210 (+) chronic myelogenous leukemia (CML), down-regulated PAK1 gene expressions may lead to the suppression of cell proliferation and promotion of apoptosis through phosphorylation of STAT5, with a reverse effect in P190 (+) acute lymphoblastic leukemia(ALL), especially acute B lymphoblastic leukemia (B-ALL).
Two models of leukemia were used, one genetic (conditional alpha4 ablation of BCR-ABL1 [p210(+)] leukemia) and one pharmacological (anti-functional alpha4 antibody treatment of primary ALL).
In this study we adapted the multiplex RT-PCR assay, previously described by Pallisgaard et al., to detect all the most frequent genetic lesions with their characteristic splicing variants occurring in acute lymphoblastic leukemia, such as the MLL/AF4, MLL/ENL, BCR/ABL p190 (e1a2) and p210 (b2a2,b3a2) isoforms, E2A/PBX1, TEL/AML1, SIL/TAL1 and the novel NUP98/RAP1GDS1 transcript, recently described in a T-ALL leukemic subtype.
This observation also confirmed that, as in de novo Ph1-positive ALL, both the P190 and P210 varieties of BCR-ABL mRNA are observed in ALL with late-appearing Ph1.
Finally, the relationship between the two common forms of BCR/ABL, the P190 and P210 configurations, and different disease phenotypes, like CML and Philadelphia (Ph1)-chromosome positive acute lymphoblastic leukemia (ALL), needs to be clarified.
The shorter p190 protein is associated almost only with ALL and AML, while the protein p210 is present in both chronic phase and blast crisis of CML and also in 50% of Philadelphia-positive (Ph1+) ALL.