Interphase cytogenetic abnormalities in chronic lymphocytic leukemia may predict response to rituximab

Select cytogenetic abnormalities such as del(17)(p13.1) and del(11)(q22-q23)predict rapid disease progression and inferior survival in chronic lymphocytic leukemia (CLL). We sought to determine the impact of the four most common interphase cytogenetic abnormalities in 28 CLL patients relative to response to three-times-a-week rituximab therapy. Abnormalities were noted in 25 of the 28 patients to include del(13)(q14.3) [n = 16 (57%)], del(11)(q22.3) [n = 10 (36%)], +12 [n = 6 (21%)], del(17)(p13.1) [n = 5 (18%)], and normal [n = 3 (11%)]. Only a minority of each of these occurred as sole abnormalities. To categorize patients into one specific group, we used the hierarchical order del(17)(p13.1) > del(11)(q22.3) > trisomy 12 > del(13)(q14.3) to prioritize. Response to rituximab was noted to vary by cytogenetic group: del(17)(p13.1), 0% [n = 5]; del(11)(q22.3), 66% [n = 9]; del(13)(q14.3), 86% [n = 7]; +12, 25% [n = 4], and normal, 0% [n = 3]. Response was significantly lower (P = 0.05) in patients with del(17)(p13.1) as compared with those with other abnormalities. These data suggest that interphase cytogenetics in CLL may be predictive of a response to rituximab therapy and provide support for additional studies validating risk-adapted therapy in this disease.