title: Expression of Fas ligand in retinoblastoma.
abstract: BACKGROUND
  The importance of the Fas-Fas ligand (FasL) mechanism for the immune evasion by tumors provided a strong rationale for the examination of FasL expression in retinoblastoma. In an earlier publication, the authors reported that invasive retinoblastomas decreased Fas expression. Because to the authors' knowledge there is not much information regarding the effect of FasL expression on retinoblastoma, the authors studied the expression of FasL in retinoblastoma and correlated it with invasiveness.
  
  
  METHODS
  Thirty-six archival retinoblastoma specimens were divided into 2 groups. Group A (n = 17) was comprised of specimens from tumors with no invasion and Group B (n = 19) was comprised of specimens from tumors with invasion of the choroid (focal, diffuse), optic nerve (laminar, postlaminar, surgical end), and orbit. Sections were immunostained with a monoclonal antibody to FasL and the immunoreactivity was assessed.
  
  
  RESULTS
  In Group A, FasL was negative in 100% (17 of 17) of the tumor specimens. In Group B, FasL was expressed in 79% (15 of 19) of the tumor specimens (positive in 9 tumors and heterogeneous in 6 tumors). The difference in FasL expression between the two groups was significant (P < 0.001)
  
  
  CONCLUSIONS
  Increased expression of FasL was observed in specimens taken from patients with aggressive tumors. Thus, Loss of Fas and gain of aberrant FasL expression were common features of malignant transformation. The data suggested that the Fas/FasL pathway is potentially immunosuppressive and may be involved in the escape of retinoblastoma cells from immune destruction.
authors.affiliation: Department of Ocular Pathology, Vision Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, India. drkrishnakumar_2000@yahoo.com
authors.forename: Subramanian
authors.initials: S
authors.lastname: Krishnakumar
authors.forename: Mallikarjuna
authors.initials: M
authors.lastname: Kandalam
authors.forename: Adithi
authors.initials: A
authors.lastname: Mohan
authors.forename: Anita
authors.initials: A
authors.lastname: Iyer
authors.forename: Nalini
authors.initials: N
authors.lastname: Venkatesan
authors.forename: Jyotirmay
authors.initials: J
authors.lastname: Biswas
authors.forename: Mahesh Palanivelu
authors.initials: MP
authors.lastname: Shanmugam
mesh_terms: D000293:Adolescent; D002471:Cell Transformation, Neoplastic; D002648:Child; D002675:Child, Preschool; D053222:Fas Ligand Protein; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D008297:Male; D008562:Membrane Glycoproteins / Q000032:analysis*; D009361:Neoplasm Invasiveness; D019572:Retinal Neoplasms / Q000737:chemistry* / Q000276:immunology / Q000473:pathology; D012175:Retinoblastoma / Q000737:chemistry* / Q000276:immunology / Q000473:pathology
chemical_list: C505661:FASLG protein, human; D053222:Fas Ligand Protein; D008562:Membrane Glycoproteins