The incidence of the reciprocal translocation
t (14;18)(q32;q21) in follicular lymphoma varies from 50% to
90% in American series. In the largest series from Europe,
the translocation was present in only 21/51 (41%) of cases.
The wide variety in incidence may in part be due to the method
of detection used - usually cytogenetics alone or a
combination of Southern blotting and polymerase chain
amplification (PCR) of DNA extracted from malignant tissue.
The shortcomings of each technique suggest that a combination
of all three may best determine the true incidence of the
This study describes and discusses the cytogenetic
analysis of lymph nodes from seventy two patients with
follicular lymphoma. Forty nine patients also had DNA
extracted from diagnostic specimens for molecular analysis
using both Southern blotting and the polymerase chain
reaction (PCR) to detect t(14;18).
The translocation was found in 76% using a combination
of all three methods. The most common other cytogenetic
abnormalities included +7, +der(18), +18, +21, +X and +8.
Cytogenetics proved the most comprehensive method of
detecting t (14 ; 18 ) and Southern blotting was superior to PCR.
The numerous additional karyotypic abnormalities present
contributed little to the management of patients with
However, molecular methods detected t(14;18) in samples
where karyotyping was unsuccessful and the stability of
t(14;18) as a marker of disease was confirmed by the finding
of molecular evidence of the translocation after analysis of
sequential samples from several patients. The increased
sensitivity of PCR allowed detection of t(14;18) bearing
cells in samples of marrow and peripheral blood stem cell
harvests from patients who were thought by conventional
criteria to be in clinical remission. As treatment of
follicular lymphoma becomes more aggressive, molecular
detection of t(14;18) will become more important in
monitoring of treatment and detection of early relapse.