Acute Promyelocytic Leukemia with i(17)(q10)

Abstract

We herein report a rare chromosomal abnormality observed in an acute promyelocytic leukemia (APL) patient. She had several APL derivative clones including a clone with i(17)(q10) abnormality, which consists of two kinds of structural abnormalities, a cryptic translocation of t(15;17) and an isochromosome of 17q. Although an obvious microscopic t(15;17) change was not observed on either arms of the isochromosome, PML/RARα fusion signals were detected on an interphase fluorescence in situ hybridization analysis. By several cytogenetic analyses of her bone marrow cells, it was confirmed that the i(17)(q10) clone was derived from the classic t(15;17) clone via another intervening clone, cryptic t(15;17).

Acute promyelocytic leukemia with torque teno mini virus (TTMV)::RARAfusion: an approach to screening and diagnosis

“…26 APL infrequently demonstrates iso(17q) or idic(17p11), where it usually co-occurs with t(15;17) resulting in an additional copy of PML::RARA but can also be an isolated finding associated with a cryptic PML::RARA . 27–29 Interestingly, two of the described cases of APL with TTMV:: RARA fusion demonstrate iso(17q) or idic(17p), suggesting that this may represent a characteristic chromosomal abnormality. Indeed, several cases of AML with promyelocytic features, iso(17q), and no detectable PML::RARA have been described, possibly representing APL with unidentified TTMV:: RARA fusions.…”

“…A final objective was to assemble and characterize a TTMV::RARA contig or contigs. To this end, various assemblers including TRINITY 21 (version 2.5.1) for RNA data and VELVET 22 (version 1.2.10 using k-mer lengths of [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] for DNA data were applied to paired-end reads with a blastn alignment of either read of the pair to TTMV, supplemented by paired-end reads where at least one read of the pair had a partial local alignment to the approximate RARA breakpoint cluster region but without a supplementary, secondary, or primary alignment resolving the 5' or 3' part of the read. The resulting contigs were then aligned to TTMV by blastn and locally aligned to the human genome by bwa mem or blat in order to maximally characterize the fusion event.…”