t(3;5)(q26;q31) H2AFY/MECOM

2018-11-01   Jean Loup Huret 



Review on t(3;5)(q26;q31) H2AFY/MECOM, with data on clinics, and the genes involved.

Clinics and Pathology


Acute myelomonocytic leukaemia (M4-AML)


Only one case to date, a 76-year-old male patient (Han et al., 2018).


He achieved complete remission (CR), but he relapsed and died 10 months after diagnosis.

Genes Involved and Proteins

Gene name
MECOM (Ecotropic Viral Integration Site 1 (EVI1) and Myelodysplastic Syndrome 1 (MDS1-EVI1)
MECOM is a nuclear transcription factor that plays an essential role in the proliferation and maintenance of hematopoietic stem cells and can inhibit myeloid differentiation. Two alternative forms exists, one generated from EVI1, the other MECOM (MDS1 and EVI1 complex locus) through intergenic splicing with MDS1 (myelodysplasia syndrome 1), a gene located 140 kb upstream of EVI1.
Protein description
The protein encoded by this gene is a transcriptional regulator involved in cell differentiation and proliferation, and apoptosis. The encoded protein can interact with transcriptional coactivators (KAT2B (P/CAF), CREBBP (CBP)) and corepressors (CTBP1, HDAC) as well as other transcription factors (GATA1, SMAD3) (de Braekeleer et al., 2012)
Gene name
H2AFY (H2A histone family member Y)
Protein description
H2AFY codes for the proteins MACROH2A1. The first exon is non-coding. Due to alternative exons 6 (coding exons 5), coding for amino acids (aa) 198-226 or 229, there are 2 isoforms. Isoform MacroH2A1.1: 369 aa; 39,1 kDa; Isoform MacroH2A1.2: 372 aa, 39,6 kDa; This protein comprises a histone H2A domain (aa: 2-117; length: 116 aa) with a HA2 signature: AGVIFPV (aa: 19-25), a Lys-rich region (aa: 118-162; length: 45 aa) with a SQ-motif (aa 139-140) which can be phosphorylated by PIKKs, and a macro domain (aa: 184-370; length: 187). Ubiquitination sites are at Lys115, Lys116 and Lys119 (Ogawa et al., 2005). Glycines (Gly224 and Gly314) are required for PAR (poly(ADP-ribose)) binding.
Protein description
MacroH2A1.1 is mainly found in differentiated, non-proliferative tissues, MacroH2A1.1 is upregulated in senescent cells; MacroH2A1.2 is more generally expressed, including in tissues with ongoing cell proliferation (Sporn and Jung 2012).
Protein description
MACROH2A1 regulates gene transcription, DNA damage response, mitochondrial respiration and senescence.
Protein description
Methylations/acetylations MacroH2A1 is found on autosomes as part of facultative heterochromatin and is localized at two functionally distinct chromatin subtypes marked by trimethylation of histone H3 on lysine 27 (H3K27me3) or as part of transcriptionally active euchromatin marked by nine histone acetylations (H2B at K15 and K20; H3 at K4, K14 and K18; H4 at K91; and H2A at K5) where it can either positively or negatively regulate transcription (reviewed in Ruiz and Gamble 2018).
Protein description
MacroH2A1.1-PARP1 axis Stressing signals generated during DNA damage repair, senescence, hormonal response, heat shock, or differentiation promote the binding of MacroH2A1.1 to activated PARP1 (poly(ADP-ribose) polymerase 1), creating the macroH2A1.1-PARP1 axis. MacroH2A1.1 recruit active PARP1 to chromatin and promotes the CREBBP -mediated acetylation of H2B K12 and K120, which either positively or negatively regulates the expression of MacroH2A1-target genes. On the other hand, when MacroH2A1.1 is highly expressed, MacroH2A1.1 can bind and inhibit PARP1 activity Chen et al., 2014; Hurtado-Bagès et al., 2018).
Protein description
MacroH2A1 regulates mitochondrial respiration MacroH2A1.1 reduces nuclear NAD+ consumption through PARP1 inhibition, allowing maintenance of mitochondrial NAD+ pools that are critical for respiration (Posavec Marjanovic et al., 2014).
Protein description
Epithelial-mesenchymal transition MacroH2A1.1 isoform, but not MacroH2A1.2, can suppress EMT induction.
Protein description
Cancer Upregulation of mH2A1 induces SKP2 subsequent CDK8 downregulation contributes to growth defect, G2/M arrest, polyploidy and tumour suppression in breast cancer (Xu et al., 2015). MacroH2A1.2, one of the MacroH2A isoforms (see above), has an intrinsic ability to inhibit breast cancer-derived osteoclastogenesis and prostate cancer-induced osteoclastogenesis. Overexpression of mH2A1.2, but not mH2A1.1, in breast cancer cells significantly increased ERBB2 expression and tumorigenicity (Li et al., 2012). Re-expression of MacroH2A1.1 suppressed cancer cell proliferation, anchorage-independent growth and cell invasiveness in breast cancer, and suppressed metastasis of melanoma through regulation of CDK8. Loss of MacroH2A1.1 was associated with cell growth and metastasis and a worse outcome in colon cancer. Conversely, MacroH2A1.2 levels have been found to be similar in all tumors independently of proliferation (Sporn and Jung 2012). Patients with low MacroH2A1.1 levels in lung tumor samples recur more likely. MacroH2A1 downregulation enhances the stem-like properties of bladder cancer cells. In contrast, in the claudin-low subtype of triple negative breast cancer ( ESR1 -, PGR -, normal ERBB2) presenting a high MacroH2A1.1 mRNA ratio exhibit a poor outcome , through epithelial-mesenchymal transition process towards metastatic development (Lavigne et al., 2014).

Result of the Chromosomal Anomaly


5H2AFY-3MECOM. The breakpoint in 5q31.1 was located in intron 5 of H2AFY, and the breakpoint in 3q26 was located in intron 1 of MECOM. H2AFY exon 5 was fused to MECOM exon 2 (Han et al., 2018).

Highly cited references

Pubmed IDYearTitleCitations
296660082018H2AFY is a novel fusion partner of MECOM in acute myeloid leukemia.3


Pubmed IDLast YearTitleAuthors
253061102014MacroH2A1.1 and PARP-1 cooperate to regulate transcription by promoting CBP-mediated H2B acetylation.Chen H et al
296660082018H2AFY is a novel fusion partner of MECOM in acute myeloid leukemia.Han Q et al
303566492018The MacroH2A1.1 - PARP1 Axis at the Intersection Between Stress Response and Metabolism.Hurtado-Bagès S et al
249118732014Increased macroH2A1.1 expression correlates with poor survival of triple-negative breast cancer patients.Lavigne AC et al
225895512012The atypical histone macroH2A1.2 interacts with HER-2 protein in cancer cells.Li X et al
161294142005Histone variant macroH2A1.2 is mono-ubiquitinated at its histone domain.Ogawa Y et al
289912662017MacroH2A1.1 regulates mitochondrial respiration by limiting nuclear NAD(+) consumption.Posavec Marjanović M et al
305101862018MacroH2A1 chromatin specification requires its docking domain and acetylation of H2B lysine 20.Ruiz PD et al
225428482012Differential regulation and predictive potential of MacroH2A1 isoforms in colon cancer.Sporn JC et al
258186432015Skp2-macroH2A1-CDK8 axis orchestrates G2/M transition and tumorigenesis.Xu D et al


Fusion gene



Jean Loup Huret

t(3;5)(q26;q31) H2AFY/MECOM

Atlas Genet Cytogenet Oncol Haematol. 2018-11-01

Online version: http://atlasgeneticsoncology.org/haematological/1837/t(3;5)(q26;q31)