title: bcl-2 and p53 protein expression in follicular lymphoma.
abstract: Recent studies have shown bcl-2 to be regulated by p53. Other studies have suggested an inverse relationship between p53 and bcl-2 protein expression in breast and colonic cancers and in a variety of subtypes of non-Hodgkin's lymphoma. This study investigates the relationship between bcl-2 and p53 protein expression and the correlation between these findings and the grade and cell type of follicular lymphomas according to the REAL classification. Paraffin-embedded nodal follicular lymphomas (n = 37) were subjected to bcl-2 and p53 immunohistochemistry on tissue sections using a three-step ABC system. Positive immunostaining for both oncoproteins was scored using a three-tiered scale: +, < 10 per cent cells; ++, 10-50 per cent cells; and ++(+), > 50 per cent cells (< 10 per cent was used as a cut-off to define negative tumours). Ninety-seven per cent (36/37) of follicular lymphomas expressed bcl-2 protein in all three grades, manifesting in the small cell (grade 1) through to the large cell (grade 3). p53 protein expression showed a pattern of increasing immunostaining with progression towards the high-grade follicular lymphoma: grade 1 = 6 per cent (1/16); grade 2 = 48 per cent (10/21); grade 3 = 100 per cent (6/6). Five cases comprised varying combinations of grades. This latter finding suggests a role for p53 mutation in the progression/transformation of follicular lymphoma. The mechanism, however, differs from that suggested in breast and colonic cancers, since an inverse relationship between bcl-2 and p53 was not demonstrated in the present study.
authors.affiliation: Department of Anatomical Pathology, School of Pathology, South African Institute for Medical Research, Johannesburg, South Africa.
authors.forename: K
authors.initials: K
authors.lastname: Cooper
authors.forename: Z
authors.initials: Z
authors.lastname: Haffajee
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D015870:Gene Expression; D006801:Humans; D007150:Immunohistochemistry; D008198:Lymph Nodes / Q000473:pathology; D008224:Lymphoma, Follicular / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D012189:Retrospective Studies; D016159:Tumor Suppressor Protein p53 / Q000032:analysis* / Q000235:genetics
chemical_list: D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53