title: pRb2/p130 protein expression and RBL2 mutation analysis in Burkitt lymphoma from Uganda.
abstract: BACKGROUND
  The members of the retinoblastoma protein family, pRb, p107 and pRb2 (p130), are central players in controlling the cell cycle. Whereas disturbed function of pRb is commonly seen in human cancers, it is still an open question whether pRb2 is involved in tumorigenic processes. However, altered subcellular localization of pRb2 and mutations in the pRb2-encoding gene RBL2 have been described for some tumours, including Burkitt lymphomas (BL).
  
  
  METHODS
  We retrieved 51 biopsy specimens of endemic BL cases from Uganda. The expression of pRb2 was determined by immunohistochemistry. Exons 1922 of the RBL2 gene, the region known to contain a nuclear localization signal, were screened for mutations by PCR amplification and direct DNA sequencing.
  
  
  RESULTS
  Nearly all of our cases (84.0%) were positive for pRb2 protein expression although this protein is a marker for growth arrest and Burkitt lymphoma is characterized by a high proliferation rate. Of the positive cases, 73.8% were scored as expressing the protein at a high level. Subcellular pRb2 localization was predominantly nuclear and no cases with expression restricted to the cytoplasm were observed. We did not detect any RBL2 mutations in the part of the gene that encodes the C-terminal end of the protein.
  
  
  CONCLUSIONS
  The majority of endemic BL cases from Uganda express pRb2, but somatic RBL2 mutations affecting the protein's nuclear localization signal appear to be rare.
authors.affiliation: Section for Pathology, the Gade Institute, University of Bergen, Bergen, Norway. skalungi@gmail.com
authors.forename: Sam
authors.initials: S
authors.lastname: Kalungi
authors.forename: Solrun J
authors.initials: SJ
authors.lastname: Steine
authors.forename: Henry
authors.initials: H
authors.lastname: Wabinga
authors.forename: Leif
authors.initials: L
authors.lastname: Bostad
authors.forename: Anders
authors.initials: A
authors.lastname: Molven
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