title: Retinoblastoma and p53 protein expression in sporadic colorectal cancers.
abstract: OBJECTIVE
  To ascertain if a relationship between retinoblastoma (pRb) and p53 proteins exists in sporadic colorectal carcinomas.
  
  
  METHODS
  Fifty consecutive colectomy specimens for colorectal cancer in patients over the age of 50 and with no family history of cancers in the bowel were examined for immunoexpression of pRb and p53 proteins. These findings were then related to clinicopathological findings. Commercially available monoclonal antibodies to pRb and p53 were used on formalin-fixed, paraffin-embedded tissue.
  
  
  RESULTS
  The most intense pRb immunoexpression was detected in well-differentiated, low-stage cancers. On the other hand, p53 expression was most intense in poorly differentiated, advanced-stage carcinomas. No statistically significant associations were noted with immunoexpression and age, gender or site of lesion.
  
  
  CONCLUSIONS
  This study indicates that there is an inverse relationship between pRb and p53 protein expression in a proportion of sporadic colorectal cancers. Twelve tumours which showed low levels of pRb showed high levels of p53 protein. Similarly, seven tumours with high pRb levels displayed low p53 expression. In terms of immunohistochemical profile, p53-high/pRb-low tumours tended to be poorly differentiated and have advanced stage cancer.
authors.affiliation: Department of Pathology, University of Natal School of Medicine, Durban, South Africa. chettyr@med.und.ac.za
authors.forename: R
authors.initials: R
authors.lastname: Chetty
authors.forename: T
authors.initials: T
authors.lastname: Subramoney
authors.forename: J P
authors.initials: JP
authors.lastname: Singh
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000737:chemistry* / Q000473:pathology; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D016160:Retinoblastoma Protein / Q000032:analysis*; D016159:Tumor Suppressor Protein p53 / Q000032:analysis*
chemical_list: D016160:Retinoblastoma Protein; D016159:Tumor Suppressor Protein p53