title: Quantitative analysis of apoptosis in retinoblastoma.
abstract: OBJECTIVE
  The rate of apoptosis in retinoblastoma (Rb) and the factors that may influence this rate, such as therapy prior to surgery, amount of necrosis in tumour tissue, differentiation and laterality of the tumour, were investigated.
  
  
  METHODS
  Thirty-one specimens (25 enucleation, six exenteration) with Rb were studied. Prior to final surgery, three patients received systemic chemotherapy, one intravitreal chemotherapy, one transpupillary thermotherapy, one external beam radiotherapy and one high-dose oral methylprednisolone therapy. The apoptotic index (AI,%) was calculated by counting at least 1000 cells under light microscopy (x 100) using TUNEL (terminal deoxynu-cleotidyl transferase-mediated dUTP nick-end labelling) method.
  
  
  RESULTS
  The mean AI was 2.75 plus minus 1.2. No statistically significant association was observed between rate of apoptosis and the presurgical treatment, extent of necrosis, tumour differentiation and laterality.
  
  
  CONCLUSIONS
  Apoptosis is an important mechanism of cell death, and may be a limiting factor for tumour progression. In this study, the rate of apoptosis was not affected by any of the studied parameters.
authors.affiliation: Ocular Oncology Service, Department of Ophthalmology, Hacettepe School of Medicine, Hacettepe University, Ankara, Turkey.
authors.forename: Sinan
authors.initials: S
authors.lastname: Tatlipinar
authors.forename: Figen
authors.initials: F
authors.lastname: Söylemezoglu
authors.forename: Hayyam
authors.initials: H
authors.lastname: Kiratli
authors.forename: Sevgül
authors.initials: S
authors.lastname: Bilgiç
mesh_terms: D017209:Apoptosis; D002648:Child; D002675:Child, Preschool; D004273:DNA, Neoplasm / Q000032:analysis; D015353:Eye Enucleation; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D020287:In Situ Nick-End Labeling; D007223:Infant; D008297:Male; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D019572:Retinal Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D012175:Retinoblastoma / Q000378:metabolism / Q000473:pathology* / Q000601:surgery
chemical_list: D004273:DNA, Neoplasm; D019253:Proto-Oncogene Proteins c-bcl-2