t(14;18) translocation is the earliet recurrent event giving rise to a BCL2-IGH fusion.
Originates from bone marrow pre-B cells.
Malignant follicular lymphoma clones are derived from the transformation of germinal center B cells in secondry lynphoid organs.
50-70 percent of healthy individuals have low levels of circulating t(14;18) positive cells, but did not develop follicular lymphoma.
BCL2 expression is necessary but not sufficient to tumor progression.
High t(14;18) frequency and bloody and healthy individuals can be predictive biomarkers for follicular lymphoma, may occur years before diagnosis .(Roulland S et al).