Significantly different bcl-2 expression profiles in gastric and non-gastric primary extranodal high-grade B-cell lymphomas.
Fifty-five cases of primary extranodal high-grade B-cell non-Hodgkin's lymphoma were investigated for bcl-2 and p53 protein expression as well as for t(14;18) translocations and p53 mutations. Phenotypic and genotypic profiles were compared between tumours of gastric (27 cases) and non-gastric (28 cases) origin. bcl-2 protein expression was significantly lower in gastric (11/27) than in non-gastric (28/28) lymphomas (p<0.0001), while nuclear p53 protein expression did not differ significantly between these two groups. In the stomach, there were no significant differences in either bcl-2 or p53 expression profiles between high-grade lymphomas with (n=14) and without (n=13) evidence of a low-grade component of MALT type. However, secondary high-grade lymphomas showed a significant down-regulation of bcl-2 protein (p<0.0001) and, conversely, an up-regulation of p53 protein (p<0.0001) as compared with their low-grade tumour components. In extranodal high-grade B-cell lymphomas, bcl-2 protein expression was not associated with t(14;18) translocation. Only one gastric lymphoma had a p53 point mutation with potential alteration of the amino acid sequence. These findings indicate that primary gastric high-grade B-cell lymphomas are immunohistologically distinct from primary extranodal high-grade B-cell lymphomas of an origin other than in the stomach.
Cogliatti
S B
SB
Department of Pathology, State Hospital, St. Gallen, Switzerland. sergio.cogliatti@kssg.ch
Griesser
H
H
Peng
H
H
Du
M Q
MQ
Isaacson
P G
PG
Zimmermann
D R
DR
Maibach
R C
RC
Schmid
U
U
D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism*; D002883:Chromosomes, Human, Pair 14; D002887:Chromosomes, Human, Pair 18; D015972:Gene Expression Regulation, Neoplastic; D016158:Genes, p53; D006801:Humans; D007124:Immunoenzyme Techniques; D016393:Lymphoma, B-Cell / Q000235:genetics / Q000378:metabolism*; D008228:Lymphoma, Non-Hodgkin / Q000235:genetics / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism*; D013274:Stomach Neoplasms / Q000235:genetics / Q000378:metabolism*; D014178:Translocation, Genetic; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
D014408:Biomarkers, Tumor; D009363:Neoplasm Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53