Immunohistochemical detection of multidrug-resistant protein expression in retinoblastoma treated by primary enucleation.
OBJECTIVE
To compare the expression of multidrug-resistant proteins in retinoblastoma tumors among eyes treated with primary enucleation.


METHODS
A group of 18 patients with unilateral retinoblastoma with advanced intraocular disease was selected for the study. All patients had undergone primary enucleation. A histologic specimen from each patient was retrieved from the pathology archives and a tissue gene microarray was constructed (0.6 x 3-4 mm). Standard immunohistochemical techniques were used to study the tissue microarrays for the expression of the ATP-binding cassette (ABC) transporters: breast cancer resistance protein (BCRP; ABCG2), multidrug-resistant protein 1/P-glycoprotein (MDR1/Pgp; ABCB1), multidrug-resistant-associated protein 1 (MRP1; ABCC1), MRP2 (ABCC2), and MRP4 (ABCC4).


RESULTS
Of the 18 specimens retrieved, 16 had adequate tissue for study. MRP1 was expressed in 8 (50%) of 16 tumors, and MRP2 was expressed in 5 (31%) of 16 tumors. MDR1/Pgp was found in 2 (12%) of 16 retinoblastomas. MRP4 and BCRP were not detected in any of the tumors studied.


CONCLUSIONS
The results show that multiple ABC transporters were present in a cohort of sporadic patients with unilateral retinoblastoma who underwent primary enucleation. Studies are planned of the expression of ABC transporters in eyes treated by chemotherapy and/or radiation as a comparison with this group.
Department of Ophthalmology, University of Tennessee Health Science Center, Memphis, Tennessee, USA. mwilson5@utmem.edu
Matthew W
MW
Wilson
Charles H
CH
Fraga
Christine E
CE
Fuller
Carlos
C
Rodriguez-Galindo
John
J
Mancini
Nikolaus
N
Hagedorn
Markos L
ML
Leggas
Clinton F
CF
Stewart
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism*; D015353:Eye Enucleation; D006801:Humans; D007124:Immunoenzyme Techniques; D026901:Membrane Transport Proteins / Q000378:metabolism; D000089762:Multidrug Resistance-Associated Protein 2; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D019572:Retinal Neoplasms / Q000378:metabolism* / Q000601:surgery; D012175:Retinoblastoma / Q000378:metabolism* / Q000601:surgery
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D026901:Membrane Transport Proteins; D000089762:Multidrug Resistance-Associated Protein 2; D027425:ATP-Binding Cassette, Sub-Family C Proteins; C000715087:ABCC2 protein, human; C421109:multidrug resistance-associated protein 1