PMC9523789_01
Morphology, FISH, and karyotyping analysis of the patient's AML bone marrow (BM) sample. (A) Promyelocytes with hypergranulated cytoplasm and invaginated nuclei (Wright-Giemsa-stained BM smear, 1,000x magnification). (B)
PML-RARA fusion signals were not detected by Interphase FISH using PML- RARA dual-color, dual-fusion translocation probes. (C) G-banded karyotype showing 46, XY [20].
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Bone marrow (BM) smear showed the hypercellularity with 41% predominantly abnormal hypergranular promyelocytes without Auer rods ( Figure 1A ). FIP1L1-RARalpha, PLZF-RARalpha, NPM-RARA, NUMA-RARalpha, STAT5-RARalpha, and PRKAR1A-RARalpha. Fluorescence in situ hybridization also failed to detect the PML-RARA fusion gene ( Figure 1B ). Cytogenetic studies did not detect the translocation of t (15;17)(q24;q21) ( Figure 1C ).
Molecular analysis of the CPSF6-RARG fusion. (A) Four fusion genes were found by analyzing RNA-sequencing data of the patient's BM sample using deFuse inspector software. (B) Schematic diagram of CPSF6, RARG, CPSF6-RARG fusion transcript, and the fusion protein of the patient. The breakpoint is indicated by a red line. (C) Sanger sequencing of the PCR product analysis of the CPSF6-RARG fusion transcript junctions revealed a fusion between exon 8 of the CPSF6 gene and exon 4 of the RARG gene.
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After analyzing the data, the patient was shown to have a rare fusion transcript within chromosome 12, in which the exon 8 of CPSF6 was fused to the exon 4 of RARG ( Figures 2A, B ). The PCR product was detected and analyzed by electrophoresis and Sanger sequencing, respectively ( Figure 2C ).