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THE FREQUENCY OF T(14;18) IN BLOOD LYMPHOCYTES IS STABLE OVER A 2 YEAR PERIOD IN ADULTS
Citation:
Scheerer, J. B., L. Xi, G W. Knapp, W. L. Bigbee, AND J C. Fuscoe. THE FREQUENCY OF T(14;18) IN BLOOD LYMPHOCYTES IS STABLE OVER A 2 YEAR PERIOD IN ADULTS. Presented at Environmental Mutagen Society, San Diego, CA, March 16-21, 2001.
Description:
The Frequency of t(14;18) in Blood Lymphocytes Is Stable over a 2 Year Period in Adults
As part of a multi-endpoint molecular epidemiology study on in utero environmental exposures, umbilical cord and adult blood lymphocytes were examined for the frequency of t(14;18) by a sensitive PCR method. This rearrangement deregulates expression of the anti-apoptotic bcl-2 gene by juxtaposition into the Ig heavy chain locus and may serve as a biomarker of lymphoid cancer risk. Prior work on 34 adults showed that the mean t(14;18) ftequency was 3 x 10-7. In the present study, one adult was found to have a ftequency of>1000 x 10-7. In order to evaluate the stability of the elevated t(14;18) frequency in this individual, blood samples were examined during a 2 year period. Blood samples from 4 other individuals with t(14;18) frequencies 10- to 1000- fold lower were also evaluated. No Statistical heterogeneity among the 4 or 5 samples taken ftom the same individual was found, demonstrating the stability of the t(14;18) ftequency over this time period in a115 individuals. The mean t(14;18) frequencies for the 5 individuals were: 1330 x 10-7, 186 x 10-7,65.6 x 10-7, 10.9 x 10-7, and 0.53 x 10-7. DNA sequencing oftranslocations ftom the individual with the highest t(14;18) ftequency showed clonal expansion ofa single t(14;18). Two hypotheses may explain these data: (1) A translocation occurred in a stem cell resulting in constant production oft(14;18)-containing cells or (2) expansion ofa t(14;18)-containing lymphocyte clone occurred with these cells being relatively long-lived because of the dysregulated bcl-2. In the second hypothesis, the initial clonal amplification is no longer occurring, resulting in a stable level oft(14;18)-containing cells.
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