The importance of t(14;18) reconstruction and better bcl-2/IgH reconstruction in the follow up of minimal residual disease (MRD) in follicular lymphoma (FL) is not clear up to now. Plenty of reasons are responsible for that. Low detection of t(14;18) by primer-specific PCR enables follow up of approximately 60% of patients with FL. Some studies doubt correlation between molecular markers and clinical response. Reconstruction was found in a few other lymphoma types, including non-malignant lymphadenopaties and even in “healthy” individuals with varying detection between 15-50%. There is a question if bcl-2/IgH can be a suitable molecular marker for FL at all. Actually, according to detailed cytogenetic studies, there is an evidence that t(14;18) is sufficiently specific for follicular lymphomas. But original idea of the only two breakpoint regions does not corresponds to reality. While breakpoint on the 14th chromosome is relatively constant, more than one third of breakpoints on 18th chromosome was identified in the region between MBR and MCR. Logically, primer-specific nested PCR for MBR and MCR can not be effective for bcl-2/IgH determination. Some new and more difficult modifications of PCR, as multiplexPCRand long-distance PCR, enable the detection of this reconstruction in 80-100 %. In addition to technical aspects, analysed compartment of residual disease has to be taken into consideration. The most measured compartment is peripheral blood because of it is easy available. There are few data definitely confirming that peripheral blood or bone marrow can reliably reflect disease which originally arise in lymph nodes. Purpose of t(14;18) follow up in MRD in follicular lymphoma is to choose appropriate technology for its detection and then to test optimal compartment for molecular determination.

        Key words: follicular lymphoma, minimal residual disease (MRD), t(14;18), bcl-2/IgH