Overexpression of MDR-related p170 glycoprotein in chronic myeloid leukemia.
METHODS
Philadelphia (Ph) positive chronic myeloid leukemia (CML) cannot be induced into a true remission with conventional chemotherapy. Blast cells and precursors obtained from 51 Ph+ CML cases were assayed for expression of the multidrug resistance (MDR)-associated glycoprotein (p170) by immunocytochemistry (APAAP) with the MRK-16 monoclonal antibody.


CONCLUSIONS
Positive cells were found in 11/17 cases in chronic phase (65%), in 4/8 cases in accelerated phase, and in 23/26 cases in blastic phase (89%). The proportion of positive cells, which ranged between less than 1% and 95%, was higher in blastic phase (mean 32 +/- 29.9) than in chronic phase (mean 3 +/- 5.3) (p = 0.006). These findings show that p170 overexpression is common in Ph+ CML, especially after progression to blastic phase, and suggest that p170-related MDR may contribute significantly to treatment failure.
Michelutti
A
A
Department of Morphologic and Clinical Research, Udine University School of Medicine, Italy.
Michieli
M
M
Damiani
D
D
Melli
C
C
Geromin
A
A
Russo
D
D
Fanin
R
R
Baccarani
M
M
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000096:biosynthesis*; D018432:Drug Resistance, Multiple / Q000502:physiology; D006801:Humans; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000097:blood*; D008970:Molecular Weight; D012189:Retrospective Studies
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1