Essential thrombocythemia with the Philadelphia chromosome and BCR-ABL gene rearrangement. An entity distinct from chronic myeloid leukemia and Philadelphia chromosome-negative essential thrombocythemia.
A 64-year-old woman presented with a platelet count of 3,225 x 10(9)/L. Bone marrow morphology showed massive megakaryocytic hyperplasia; cytogenetic studies showed the presence of the Philadelphia chromosome (Ph). The presence of a rearrangement involving the major breakpoint cluster region (mbcr) on chromosome 22 was confirmed by Southern blotting techniques. A diagnosis of Ph positive essential thrombocythemia (ET) was made. Such cases constitute less than 5% of patients with ET and it has been proposed that they be considered examples of chronic myelogenous leukemia (CML) because of a shared propensity to progress to blast crisis. An argument is presented for retaining Ph positive ET as an entity separate from Ph negative ET and Ph positive CML.
LeBrun
D P
DP
Department of Laboratory Haematology, Sunnybrook Medical Centre, Toronto, Ontario, Canada.
Pinkerton
P H
PH
Sheridan
B L
BL
Chen-Lai
J
J
Dubé
I D
ID
Poldre
P A
PA
D015139:Blotting, Southern; D001853:Bone Marrow / Q000473:pathology; D002899:Chromosomes, Human, Pair 9; D004273:DNA, Neoplasm / Q000235:genetics; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology; D008875:Middle Aged; D011505:Protein-Tyrosine Kinases; D011518:Proto-Oncogene Proteins / Q000235:genetics; D051562:Proto-Oncogene Proteins c-bcr; D013920:Thrombocythemia, Essential / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology; D014178:Translocation, Genetic
D004273:DNA, Neoplasm; D011518:Proto-Oncogene Proteins; D011505:Protein-Tyrosine Kinases; C496613:BCR protein, human; D051562:Proto-Oncogene Proteins c-bcr