[BCL-2 gene in lymphocytic malignancy].
In t(14;18) (q32;q21) lymphomas, bcl-2 gene is activated by the juxtaposition of immunoglobulin (Ig) gene. The fused bcl-2-Ig gene generates chimeric mRNAs which consist of bcl-2 at 5' portion and Ig at 3' portion. Chimeric mRNA does not disrupt the bcl-2 coding frame of 239 amino acid polypeptide. Bcl-2-Ig transgenic mice demonstrated the extended B cell survival and the follicular lymphoproliferation, but they did not develop a malignancy until 25 weeks. Ten percent of them, however, developed malignant diffuse large-cell lymphomas after a long latency. Forty percent of these malignancies demonstrated the c-myc rearrangement, indicating that multiple step changes are required for malignant transformation in bcl-2 activated cells. Study on the bcl-2 gene rearrangement in Japanese B cell lymphoma and B-CLL revealed that 10 out of 32 cases of follicular lymphoma (31%), 5 out of 56 cases of diffuse lymphoma (9%) and 2 out of 30 cases of B-CLL (7%) were rearranged. Less frequency of B cell lymphoma, particularly follicular lymphoma in Japan might be partly due to the less bcl-2 involvement than in American cases. The ratio of bcl-2 involvement in B-CLL is not significantly different between Japan and U.S.A.. bcl-2 rearrangement at 5' promoter region is noted for Japanese B-CLL which was demonstrated for American cases. The clinical application of polymerase chain reaction for bcl-2 translocation was also discussed.
Seto
M
M
Laboratory of Chemotherapy, Aichi Cancer Center Research Institute.
Yamamoto
K
K
Osada
H
H
Ueda
R
R
D000818:Animals; D015321:Gene Rearrangement / Q000235:genetics*; D015322:Gene Rearrangement, B-Lymphocyte / Q000235:genetics; D015326:Gene Rearrangement, B-Lymphocyte, Heavy Chain; D005803:Genes, Immunoglobulin; D006801:Humans; D016393:Lymphoma, B-Cell / Q000235:genetics*; D008224:Lymphoma, Follicular / Q000235:genetics; D051379:Mice; D008822:Mice, Transgenic; D009857:Oncogenes; D014178:Translocation, Genetic