Philadelphia chromosome-negative chronic myelogenous leukemia with rearrangement of the breakpoint cluster region. Long-term follow-up results.
BACKGROUND
Five to 10% of patients with chronic myelogenous leukemia (CML) do not have the Philadelphia chromosome (Ph), but one-third of them have rearrangements of the breakpoint cluster region (BCR-positive).


METHODS
The authors analyzed the characteristics, treatment response, and prognosis of 23 patients with BCR-positive, Ph-negative CML, and compared them with patients with Ph-positive CML, Ph-negative BCR-negative CML and chronic myelomonocytic leukemia (CMML) treated during the same period.


RESULTS
Seventeen patients had early chronic phase CML, 3 had late chronic phase, 2 had accelerated phase, and 1 had blastic phase. The median age was 44 years (range, 14-71 years), median platelet count was 402 x 10(9)/l, and median leukocyte count was 86 x 10(9)/l. Fourteen of the 17 patients with early chronic phase CML received alpha-interferon; 12 (86%) achieved complete hematologic remission. Median survival in chronic phase CML was 60 months (range, 3-90+ months). Patients with Ph-negative BCR-positive CML and those with Ph-positive CML had similar characteristics and outcome. Compared with patients with Ph-negative BCR-negative CML and CMML, patients with Ph-negative BCR-positive CML and Ph-positive CML were significantly younger, had a significantly higher incidence of leukocytosis, thrombocytosis, and peripheral and marrow basophilia, and a significantly lower incidence of anemia, thrombocytopenia, marrow blast percent, and peripheral and marrow monocytosis. The median survival was 60 months for Ph-negative BCR-positive CML, 73 months for Ph-positive CML, 25 months for Ph-negative BCR-negative CML, and 9 months for CMML (P < 0.001). When analyzed adjusting for their stage, patients classified with Ph-negative BCR-positive CML. Stage I disease had a significantly better survival than did patients with Ph-negative BCR-negative CML (P < 0.02).


CONCLUSIONS
Patients with Ph-negative BCR-positive CML are similar to those with Ph-positive CML and should be treated with the same approaches.
Cortes
J E
JE
Department of Hematology, University of Texas M.D. Anderson Cancer Center, Houston 77030.
Talpaz
M
M
Beran
M
M
O'Brien
S M
SM
Rios
M B
MB
Stass
S
S
Kantarjian
H M
HM
D000293:Adolescent; D000328:Adult; D000368:Aged; D001772:Blood Cell Count; D005500:Follow-Up Studies; D015321:Gene Rearrangement; D006801:Humans; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000097:blood / Q000235:genetics / Q000401:mortality; D054438:Leukemia, Myeloid, Chronic, Atypical, BCR-ABL Negative / Q000097:blood / Q000235:genetics / Q000401:mortality*; D015466:Leukemia, Myeloid, Chronic-Phase / Q000235:genetics / Q000401:mortality* / Q000628:therapy; D008875:Middle Aged