P-glycoprotein expression and multidrug resistance in cutaneous T-cell lymphoma.
Advanced-stage cutaneous T-cell lymphoma (CTCL) is generally resistant to standard chemotherapy. Because P-glycoprotein (P-gp) has been detected in other types of resistant solid tumors, leukemias, and lymphomas, we analyzed P-gp expression in CTCL. Twenty-seven patients with CTCL and circulating Sezary cells in the peripheral blood as observed on a peripheral smear treated at the Yale Photopheresis Center between 1987 and 1993 were identified. Twenty-five of these patients had skin biopsies evaluated for expression of P-gp using JSB-1 (Accurate Chemical), MRK-16 (gift of T. Tsuruo), and UIC-2 (gift of E. Metchner). P-gp expression was considered present if immunoreactivity was noted with two of the three antibodies. Eighteen of 25 patients (72%) evaluated exhibited expression. The patients were treated with various combinations of drugs consisting of topical and systemic steroids electron beam therapy, psoralens in combination with UV light A (PUVA), systemic chemotherapy, and photopheresis before testing the tissue for P-gp expression. Treatment with systemic chemotherapy in P-gp-positive patients produced responses in 3 and no responses in 11 patients (4 were lost to follow-up). Seven patients did not express P-gp: One patient responded to treatment, five did not respond, and one patient was lost to follow-up. These results demonstrate that P-gp is frequently expressed in CTCL. P-gp expression in our study was not a useful predictor of drug resistance.
Jillella
A P
AP
Yale University School of Medicine, Comprehensive Cancer Center, New Haven, Connecticut, USA. AJILLELL@MAIL.MCG.EDU
Murren
J R
JR
Hamid
K K
KK
Longley
B J
BJ
Edelson
R L
RL
Cooper
D L
DL
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000032:analysis*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018432:Drug Resistance, Multiple; D019008:Drug Resistance, Neoplasm; D005260:Female; D006801:Humans; D016410:Lymphoma, T-Cell, Cutaneous / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D008297:Male; D008875:Middle Aged
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1