Relationship between histopathological features of chemotherapy treated retinoblastoma and P-glycoprotein expression

Background: P‐glycoprotein (P‐gp) has been identifiedas a possible mediator of chemoresistance in retinoblastoma. Theaim of this study was to determine the expression of P‐gp in retinoblastomatreated with chemotherapy prior to enucleation. Methods: Seventeen enucleated specimens of retinoblastomafro...

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Published in:	Clinical & experimental ophthalmology Vol. 33; no. 3; pp. 279 - 284
Main Authors:	Souza Filho, João P, Martins, Maria C, Caissie, Amanda L, Torres, Virginia LL, Fernandes, Luiza HCF, Erwenne, Clelia M, Burnier Jr, Miguel N
Format:	Journal Article
Language:	English
Published:	Oxford, UK Blackwell Science Pty 01-06-2005
Subjects:	Antineoplastic Combined Chemotherapy Protocols - therapeutic use ATP-Binding Cassette, Sub-Family B, Member 1 - metabolism Brachytherapy Carboplatin - administration & dosage chemotherapy Child, Preschool Combined Modality Therapy Etoposide - administration & dosage Female histopathology Humans Immunoenzyme Techniques immunohistochemistry Infant Male Neoplasm Invasiveness P-glycoprotein Retinal Neoplasms - drug therapy Retinal Neoplasms - metabolism Retinal Neoplasms - pathology retinoblastoma Retinoblastoma - drug therapy Retinoblastoma - metabolism Retinoblastoma - pathology Vincristine - administration & dosage
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Summary:	Background: P‐glycoprotein (P‐gp) has been identifiedas a possible mediator of chemoresistance in retinoblastoma. Theaim of this study was to determine the expression of P‐gp in retinoblastomatreated with chemotherapy prior to enucleation. Methods: Seventeen enucleated specimens of retinoblastomafrom 16 patients were studied. Nine had been treated with chemotherapyalone, and eight had been treated with chemotherapy and other formsof local treatment. Tumour differentiation as well as choroidaland optic nerve invasion were assessed. P‐gp immunohistochemicalstaining was performed and evaluated as negative, low or high. Results: Histopathological assessment of thecases showed that 14 of 17 eyes (82.3%) had viable retinoblastomacells. Nine retinoblastomas were considered regressed with a well‐differentiatedcomponent, five regressed retinoblastomas had viable cells withpoor differentiation and three retinoblastomas had regressed leavingno viable cells. Sixteen of 17 retinoblastomas were P‐gp positive.In the one case with optic nerve invasion and the three cases with massivechoroidal invasion, P‐gp expression was found in invading retinoblastomacells. Conclusion: Almost all retinoblastomas expressedP‐gp. High levels of P‐gp expression might play a role in chemotherapyresistance of retinoblastoma or, conversely, chemotherapymight induce P‐gp expression. These results might have an impacton management of bilateral retinoblastoma.
Bibliography:	istex:3B20B54165718BADDBF77075D04568CDD7B426AA ArticleID:CEO991 ark:/67375/WNG-6QSXRLWC-D ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	1442-6404 1442-9071
DOI:	10.1111/j.1442-9071.2005.00991.x