Detection of chromosomal abnormalities by G-banding and prognostic impact in follicular lymphoma in the rituximab era

Disease-specific cytogenetic abnormalities involving BCL2 gene rearrangement frequently co-exist with other cytogenetic abnormalities, contributing to disease progression in follicular lymphoma (FL). In the present study, we retrospectively investigated the prognostic impact of BCL2-unrelated cytogenetic abnormalities in FL. Of 139 consecutively diagnosed patients with FL at two independent institutes, metaphase spreads of tumor cells were obtained for use in G-banding analysis in 77 patients. The recurrent additional cytogenetic abnormalities included chromosome gains +5 (n = 8), +7 (n = 16), +12 (n = 10), and +X (n = 12), and losses −8 (n = 7), −13 (n = 12) −15 (n = 7), and 6q− (n = 7). While −15 was associated with shorter progression-free survival (PFS) in all 77 analyzed patients with evaluable G-banding results (p = 0.04), this negative impact was not evident in 42 patients treated using an R-CHOP-like regimen as first-line treatment. By contrast, 6q− was predictive for shorter PFS in patients who were initially treated with R-CHOP-like regimens without maintenance therapy (p < 0.01), while this negative impact was not evident in all 77 patients with evaluable G-banding results. These results suggest the presence of a molecular region in chromosome 6q that is responsible for the shorter PFS following R-CHOP-like chemotherapy.