Flow cytometric measurement of phosphorylated STAT5 in AML: Lack of specific association with FLT3 internal tandem duplications

Pallis, Monica; Seedhouse, Claire; Grundy, Martin; Russell, Nigel

Abstract

STAT5 phosphorylation has been noted in 69–95% of AML cases by Western blotting. We used flow cytometry to measure phosphorylated STAT5 on a semi-quantitative scale. The method was validated on K562 cells, which constitutively express phosphorylated STAT5, but lose this when BCR-abl tyrosine kinase activity is blocked by STI571. Phosphorylated STAT5 was found to measure 2.22±0.09 relative fluorescence units (RFU) falling to 0.925±0.005 RFU in the presence of STI571. Phosphorylated STAT5 expression was 0.99 to 2.09 RFU in 28 primary AML samples. There was no logical cut-off point between positive and negative fluorescence. FLT3 internal tandem duplications, found in 11/28 samples, were not significantly associated with the level of phosphorylated STAT5 expression. We conclude that STAT5 phosphorylation can be measured sensitively by flow cytometry in AML and that its expression should not be dichotomised as present or absent.

Citation

Pallis, M., Seedhouse, C., Grundy, M., & Russell, N. (2003). Flow cytometric measurement of phosphorylated STAT5 in AML: Lack of specific association with FLT3 internal tandem duplications. Leukemia Research, 27(9), 803-805. https://doi.org/10.1016/S0145-2126%2803%2900012-2

• Journal Article Type: Article
• Acceptance Date: Dec 21, 2002
• Online Publication Date: Feb 18, 2003
• Publication Date: 2003-09
• Deposit Date: Apr 5, 2024
• Journal: Leukemia Research
• Print ISSN: 0145-2126
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 27
• Issue: 9
• Pages: 803-805
• DOI: https://doi.org/10.1016/S0145-2126%2803%2900012-2
• Keywords: AML, Phosphorylated STAT5, FLT3 ITD
• Public URL: https://nottingham-repository.worktribe.com/output/32755133
• Publisher URL: https://www.sciencedirect.com/science/article/pii/S0145212603000122?via%3Dihub