title: Clinicopathological parameters and expression of P-glycoprotein and MRP-1 in retinoblastoma.
abstract: OBJECTIVE
  The immunohistochemical expressions of two multidrug resistance proteins, P-glycoprotein (P-gp) and multidrug resistance-related protein-1 (MRP-1), were studied in retinoblastoma and the correlations with the clinicopathological parameters were assessed.
  
  
  METHODS
  Sixty-five enucleated eyes containing retinoblastoma were included in the study. Following hematoxylin-eosin staining, tumor differentiation, presence of choroidal invasion, optic nerve invasion, retinal invasion, necrosis and presence of calcification were evaluated with the light microscope. P-gp and MRP-1 expressions were evaluated immunohistochemically.
  
  
  RESULTS
  Fifty-three eyes were enucleated primarily and 12 eyes were operated after failure of chemotherapy. P-gp and MRP-1 expressions were positive in 69.3 and 73.4% of specimens, respectively. There was no statistically significant relationship between the expressions of P-gp and MRP-1, and tumor differentiation, presence of tumor invasion or treatment with chemotherapy.
  
  
  CONCLUSIONS
  Retinoblastoma intrinsically expresses both P-gp and MRP-1 and their expressions are not related to tumor differentiation. The expressions of P-gp and MRP-1 do not seem to be induced by chemotherapy and are not related to the degree of tumor invasion.
authors.affiliation: Department of Ophthalmology, Hacettepe University School of Medicine, Ankara, Turkey.
authors.forename: Günhal
authors.initials: G
authors.lastname: Kamburoğlu
authors.forename: Hayyam
authors.initials: H
authors.lastname: Kiratli
authors.forename: Figen
authors.initials: F
authors.lastname: Söylemezoğlu
authors.forename: Sevgül
authors.initials: S
authors.lastname: Bilgiç
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D015353:Eye Enucleation; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D008297:Male; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000378:metabolism*; D019572:Retinal Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology*; D012175:Retinoblastoma / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology*
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D027425:ATP-Binding Cassette, Sub-Family C Proteins; C421109:multidrug resistance-associated protein 1