Abstract

Many kinds of genetic changes have been known to be associated with malignant lymphoma and bcl-2, p53 and c-myc are some examples. We investigated the expression of p53 and c-myc protein in follicular and diffuse B cell lymphoma by immunohistochemistry to study the possible role of these proteins in the lymphomagenesis and transformation of the tumor. The rearrangement of bcl-2 oncogene and the immunoglobulin heavy chain gene was searched for in those cases by polymerase chain reaction(PCR). Paraffin-embedded tissues of fifteen follicular lymphomas and 14 diffuse lymphoma cases were used. The results of immunohistochemical staining are summarized as follows: 1) p53 positivity is significantly higher in diffuse lymphoma than in follicular lymphoma(P=0.001); 2) c-myc expression is not increased in diffuse lymphoma compared with follicular lymphoma; 3) PCNA index is significantly higher in diffuse lymphoma than in follicular lymphoma(P=0.03) but there was no statistically significant correlation between PCNA index and p53 positivity(P=0.44); 4) Eight out of 14 cases of follicular lymphoma and 12 of 14 cases of diffuse lymphoma showed rearrangement of the immunogloblulin heavy chain gene; 5) bcl-2 oncogene rearrangement was identified in only one case of follicular lymphoma and all the diffuse type lymphomas were negative in bcl-2/IgH rearrangement. In conclusion, assuming that the follicular pattern of B-cell lymphoma often transforms to diffuse type in later stages, c-myc over-expression might be an earlier event than p53 mutation in the process of tumor progression in B-cell lymphoma. bcl-2/IgH gene rearrangement in follicular lymphoma is a rare finding in Korea compared to that of Western countries.

• Keywords: p53;c-myc;bcl-2;PCNA;Lymphoma;