title: Expression of pro-apoptotic Bax and anti-apoptotic Bcl-2 proteins in human retinoblastoma.
abstract: BACKGROUND
  Regulation of apoptosis is a complex process that involves a number of genes, including Bcl-2, Bcl-x, Bax and other Bcl-2 family members. The aim of the present study is to assess the expression of Bcl- 2 and Bax in retinoblastoma, and correlate them with clinical and histopathological parameters.
  
  
  METHODS
  The expression of Bcl-2 and Bax proteins were examined using immunohistochemistry, Western blotting and reverse transcriptase-polymerase chain reaction in a series of 60 prospective cases of primary retinoblastoma tissues.
  
  
  RESULTS
  Immunohistochemistry showed expression of Bcl-2 in 40/60 (66.6%), whereas Bax expression was found only in 18/60 (30%) cases, and these correlated with mRNA expression. The Western blotting results also correlated well with the immunohistochemical expression of Bcl-2 (25 kDa) and Bax (21 kDa) proteins. Bcl-2 was expressed in 96% (24/25) of invasive tumours and in 45.7% (16/35) of non-invasive tumours. Expression of Bcl-2 significantly correlated with tumour invasiveness (P = 0.0274) and poor differentiation (P = 0.0163), whereas loss of Bax correlated with massive choroidal invasion and Pathological Tumor-Node-Metastasis (pTNM) (P = 0.0341). However, no correlation was found between Bax and Bcl-2 expression.
  
  
  CONCLUSIONS
  Our findings suggest that these apoptotic regulatory proteins may serve as poor prognostic markers and can be used as a therapeutic target for the treatment of invasive retinoblastoma. Further functional studies are required to explore the role of Bax and Bcl-2 in retinoblastoma.
authors.affiliation: Department of Ocular Pathology, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Lata
authors.initials: L
authors.lastname: Singh
authors.forename: Neelam
authors.initials: N
authors.lastname: Pushker
authors.forename: Neeru
authors.initials: N
authors.lastname: Saini
authors.forename: Seema
authors.initials: S
authors.lastname: Sen
authors.forename: Anjana
authors.initials: A
authors.lastname: Sharma
authors.forename: Sameer
authors.initials: S
authors.lastname: Bakhshi
authors.forename: Bhavna
authors.initials: B
authors.lastname: Chawla
authors.forename: Seema
authors.initials: S
authors.lastname: Kashyap
mesh_terms: D017209:Apoptosis; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism*; D015153:Blotting, Western; D002675:Child, Preschool; D005260:Female; D015870:Gene Expression / Q000502:physiology; D052138:Genes, Neoplasm / Q000502:physiology; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D009363:Neoplasm Proteins / Q000235:genetics; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D019572:Retinal Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D012175:Retinoblastoma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051028:bcl-2-Associated X Protein / Q000235:genetics / Q000378:metabolism*
chemical_list: D014408:Biomarkers, Tumor; D009363:Neoplasm Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D051028:bcl-2-Associated X Protein
keywords: Bax; Bcl-2; apoptosis; immunohistochemistry; retinoblastoma