Figure 1.

The current model of FL development. Follicular lymphoma biological complexity is depicted as resulting from a multihit pathway escalating along B cell differentiation stages over years/decades. Several premalignant intermediates have been identified or inferred as “precursors” or “CPC,” each of which could be at the origin of relapses. Characterizing such different CPC flavors (molecular/phenotypic/functional) is a current major challenge in the field. The arrows depict the supposed trajectory of follicular lymphoma precursor cells along the normal B cell differentiation path. BM = bone marrow; CPC = committed precursor clones; GC = germinal center; FL = follicular lymphoma; FLLC = follicular lymphoma like cells; ISFN = in situ follicular neoplasia; LN = lymph node; tFL = transformed follicular lymphoma.