t(X;17)(p11;q21) BCOR/RARA

2012-01-01   Yukiya Yamamoto 

1.Department of Hematology, Fujita Health University, 1-98 Dengakugakubo, Kutsukake-cho, Toyoake, Aichi 470-1192, Japan

Clinics and Pathology



Very rare. One case has been reported.


A bone marrow sample was markedly hypercellular, containing 83% promyelocytes. Coagulopathy was present with an increased prothrombin time, an activated partial thromboplastin time, decreased fibrinogen, and mildly increased fibrin/fibrinogen degradation products.
Atlas Image
Rectangular cytoplasmic bodies and round inclusions are found in some of hypergranular promyelocytes. May-Giemsa staining.


Bone marrow promyelocytes were strongly positive for Sudan black B, myeloperoxidase staining and naphthol AS-D chloroacetate staining and negative for alpha-naphthyl butyrate staining. Flow cytometric analysis: HLA-DR-/CD13+/CD33+/CD56+.


Conventional chemotherapy plus ATRA achieved complete remission, followed with consolidation therapies. However, 35 months after diagnosis, the patient relapsed and cord blood transplantation was performed with a myeloablative conditioning regimen. After engraftment was achieved, a bone marrow sample showed third CR. The patient demonstrated overt coagulopathy, sensitivity to ATRA, but resistance to arsenic trioxide.


Atlas Image
FISH analysis (Vysis LSI PML/RARA dual color, dual fusion translocation probe, Vysis; Downers Grove, IL). One of the RARA signals (green) is split. PML signals (red) are intact.

Genes Involved and Proteins

Gene name
BCOR (BCL6 corepressor)
Protein description
The BCL6 co-repressor, BCOR, is a ubiquitously expressed nuclear protein which directly interfaces to proto-oncoprotein BCL6. BCOR also associates with HDACs, the polycomb group protein PCGF1/NSPC1 and the histone demethylase FBXL10, which implies that it could suppress gene transcription by epigenetic mechanisms.
Gene name
RARA (Retinoic acid receptor, alpha)
Protein description
Wide expression; nuclear receptor; binds specific DNA sequences: HRE (hormone response elements); ligand and dimerization domain; role in growth and differentiation.

Result of the Chromosomal Anomaly

Atlas Image
Schematic diagram of RARA, BCOR and the BCOR-RARA fusion protein. The break point is indicated by the black line. Ankyrin repeats (ANK).


BCOR cDNA (isoform b; reference NM_001123384) from exons 1 to 12 to be fused to RARA exon 3. Full length chimeric fusion transcripts spanning from the start codon to 4948 nt of BCOR cDNA fused to RARA cDNA from exon 3 to the stop codon. A reciprocal chimeric cDNA of RARA-BCOR was not detected.


BCOR-RARA had a BCORBBD (498~514 aa), three Ankyrin repeats (1410~1509 aa) of BCOR, a DNA binding domain (DBD) derived from RARA (1557~1622 aa) and a ligand binding domain of RARA (1669~1888 aa).

Expression localisation

BCOR-RARA localized as two patterns; (I) diffusely in the nucleus as well as PML-RARA, (II) diffusely in the nucleus and aggregately in the cytoplasm. The subcellular localization of BCOR-RARA was clearly distinguishable from the punctuate pattern shown in the nucleus of BCOR-expressing cells.


BCOR-RARA was found to possess common features with other RARA fusion proteins. These included: (I) the same break point in RARA cDNA; (II) self-association; (III) RXRA is necessary for BCOR-RARA to associate with the RARA responsive element; (IV) action in a dominant-negative manner on RARA transcriptional activation; (V) aberrant subcellular relocalization.

Highly cited references

Pubmed IDYearTitleCitations
208078882010BCOR as a novel fusion partner of retinoic acid receptor alpha in a t(X;17)(p11;q12) variant of acute promyelocytic leukemia.49
257909012015Successful treatment of acute promyelocytic leukemia with a t(X;17)(p11.4;q21) and BCOR-RARA fusion gene.12


Pubmed IDLast YearTitleAuthors
208078882010BCOR as a novel fusion partner of retinoic acid receptor alpha in a t(X;17)(p11;q12) variant of acute promyelocytic leukemia.Yamamoto Y et al


Fusion gene

BCOR/RARA BCOR (Xp11.4) RARA (17q21.2) M t(X;17)(p11;q21)|BCOR/RARA BCOR (Xp11.4) RARA (17q21.2) TIC
Atlas Image
t(X;17)(p11;q12), G-banding.


Yukiya Yamamoto

t(X;17)(p11;q21) BCOR/RARA

Atlas Genet Cytogenet Oncol Haematol. 2012-01-01

Online version: http://atlasgeneticsoncology.org/haematological/1594/t(x;17)(p11;q21)