title: BCL2 gene abnormalities define distinct clinical subsets of follicular lymphoma.
abstract: OBJECTIVE
  Follicular lymphoma (FL) arising primarily in the skin has recently been proposed as a distinct entity on the basis of a low incidence of t(14;18)(q32;q21) and bcl-2 expression, with a very high percentage of patients surviving more than 5 years. However, cases of t(14;18)(q32;q21)-positive primary cutaneous FL (PCFL) and examples of t(14;18)(q32;q21)-negative FL at nodal and other extranodal sites, are well documented. The aim of this study was to test the hypothesis that there is a subtype of FL lacking t(14;18)(q32;q21), which preferentially involves certain sites but is not restricted by anatomical location.
  
  
  RESULTS
  A cohort of 47 stage 1 FL was stratified according to the presence or absence of t(14;18)(q32;q21) using conventional cytogenetics, polymerase chain reaction and interphase fluorescence in situ hybridization. Compared with t(14;18)(q32;q21)-positive cases, FL lacking the translocation were less likely to express CD10 or bcl-2 (P<0.01), made up a significantly greater proportion of cases arising at extranodal sites (P<0.001) and had a significantly better overall and disease-specific 5-year survival (P<0.01).
  
  
  CONCLUSIONS
  These results support the concept of a subtype of FL lacking t(14;18)(q32;q21), characterized by low-intensity bcl-2 expression, a predilection for extranodal sites, particularly the skin, and a more favourable outcome than t(14;18)(q32;q21)-positive FL.
authors.affiliation: Department of Pathology, Western General Hospital, Edinburgh, and Division of Pathology and Neuroscience, University of Dundee, UK. john.goodlad@luht.scot.nhs.uk
authors.forename: J R
authors.initials: JR
authors.lastname: Goodlad
authors.forename: P J
authors.initials: PJ
authors.lastname: Batstone
authors.forename: D A
authors.initials: DA
authors.lastname: Hamilton
authors.forename: N M
authors.initials: NM
authors.lastname: Kernohan
authors.forename: D A
authors.initials: DA
authors.lastname: Levison
authors.forename: J M
authors.initials: JM
authors.lastname: White
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002869:Chromosome Aberrations; D002883:Chromosomes, Human, Pair 14 / Q000235:genetics; D002887:Chromosomes, Human, Pair 18 / Q000235:genetics; D005260:Female; D019254:Genes, bcl-2; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008224:Lymphoma, Follicular / Q000145:classification* / Q000235:genetics* / Q000401:mortality; D008297:Male; D008875:Middle Aged; D015260:Neprilysin / Q000096:biosynthesis; D016133:Polymerase Chain Reaction; D011379:Prognosis; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis; D016019:Survival Analysis; D014178:Translocation, Genetic
chemical_list: D019253:Proto-Oncogene Proteins c-bcl-2; D015260:Neprilysin