Cytogenetic aberrations and their prognostic value in a series of 330 splenic marginal zone B-cell lymphomas: a multicenter study of the Splenic B-Cell Lymphoma Group

We conducted a retrospective collaborative study to cytogenetically characterize Splenic Marginal Zone Lymphoma (SMZL) and ascertain the prognostic value of chromosomal aberrations. Of 330 cases, 72% displayed an aberrant karyotype, 53% were complex while 29% had a single aberration. The predominant aberrations were gains of chromosomes 3/3q and 12q, deletions of 7q and 6q and translocations involving 8q/1q/14q. CD5 expression was detected in 39/158 cases (25%) with available information. The cytogenetic makeup of the CD5+ group differed significantly from that of the CD5- group. Cases with unmutated IGHV genes were significantly associated with deletions of 7q and TP53. A strong association was noted between usage of the IGVH1-2 gene and deletion 7q, 14q alterations and abnormal karyotype. On univariate analysis, patients with >/=2 cytogenetic aberrations, 14q alterations and TP53 deletions had the shortest survival; 7q deletion did not affect survival. On multivariate analysis, cytogenetic aberrations did not retain prognostic significance; the only parameters negatively affecting survival were hemoglobin and age. In conclusion, the cytogenetic profile of SMZL is distinct from that of other B-cell lymphomas. Complexity of the karyotype, 14q aberrations and TP53 deletions are poor prognostic indicators and may be considered together with other clinicobiological parameters to ascertain the prognosis of SMZL.