Abstract:
The hypermethylation of p16ink4a and
p15ink4b genes have been described as an inactivating
mechanism alternative to deletions and mutations that
accounts for a relatively high proportion of cancers,
including non-Hodgkin's lymphomas (NHLs). To investigate
whether detection of abnormal methylation could have
clinical applications in the management and follow-up of
lymphomas, we have analysed the behaviour and evolution
of p16ink4a and p15ink4b methylation in 13 NHL cases
undergoing chemotherapy. All cases were also analysed for
the presence of monoclonal rearrangements of immunoglo bulin or T-cell receptor genes. Six patients showed methyla tion in at least one of these genes at diagnosis, whereas in
two other cases methylation appeared during the treatment.
The other five cases were always unmethylated. Methylation
was detected when any histological or molecular evidence of
disease was present, suggesting a good correlation between
methylation and disease. In some cases, we were able to
detect methylation in patients at complete remission and
without evidence of monoclonal cell population, indicating
a high sensitivity of the PCR to detect methylation. These
results suggest that p16ink4a and p15ink4b methylation
could be good markers of disease and could be helpful in
identifying lymphoma patients at risk of relapse.
