Additional sex combs like transcriptional regulator 1 (official symbol ASXL1) is a gene that codes for a chromatin-binding
protein. Normal ASXL1 plays a role in
embryonic development (Gene 2014). ASXL1 mutations are observed
primarily in myelodysplastic syndromes, but they are also observed in colorectal and
endometrial cancers (COSMIC).
Suggested Citation: Strickland, S., A. Kim. 2015. ASXL1. My Cancer
(Updated December 4).
Last Updated: December 4, 2015
ASXL1 in Myelodysplastic Syndromes
ASXL1 mutations occur in 15.8% of MDS (COSMIC). ASXL1 and EZH2 mutations—both genes that code for
chromatin-modifying proteins—are most often observed in refractory cytopenia with
multilineage dysplasia (RCMD) and refractory anemia with excess blasts (RAEB), two subtypes
of MDS associated with higher risk (Cazzola, Della Porta, and Malcovati
2013). ASXL1 mutations, 70% of which are frameshift mutations (Thol et al.
2011), result in loss of ASXL1 expression, which ultimately results in loss of
polycomb repressive complex 2 (PRC2)-mediated gene repression. PRC2 normally represses the
expression of several leukemogenic genes. This loss promotes myeloid transformation and
et al. 2012).
ASXL1 mutations are a prognostic biomarker,
associated with shorter overall survival (Bejar et al.
2011; NCCN 2014; Thol et al.
Suggested Citation: Strickland, S., A. Kim. 2014. ASXL1 in Myelodysplastic
Syndromes. My Cancer Genome https://www.padiracinnovation.org/content/disease/myelodysplastic-syndromes/asxl1/
(Updated September 30).
Last Updated: September 30, 2014
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