Several additional promyelocytic/retinoic acid receptor-alpha (PML/RARalpha) transcripts besides bcr1, bcr2, and bcr3 have been identified in patients with acute promyelocytic leukemia (APL).
We report the case of a 38-year-old man with acute promyelocytic leukemia (APL) showing a distinct breakpoint cluster region 2 (bcr2) variant transcript.
Often bcr1 and bcr2 are reported together; 862 (60%) of 1429 non-Latino APL patients reported in nine studies were either bcr1 or bcr2, compared with 44 (85%) in our 52 Latino patients.
Molecular studies on a large series of APLs revealed great heterogeneity of the PML/RAR alpha transcripts due to: (i) variable breaking of chromosome 15 within three PML breakpoint cluster regions (bcr1, bcr2 and bcr3), (ii) alternative splicings of the PML portion and (iii) alternative usage of two RAR alpha polyadenylation sites.