Proliferation centers in chronic lymphocytic leukemia: correlation with cytogenetic and clinicobiological features in consecutive patients analyzed on tissue microarrays

To better define the significance of proliferation centers (PCs), the morphological hallmark of chronic lymphocytic leukemia (CLL), lymph node biopsies taken from 183 patients were submitted to histopathologic and fluorescence in situ hybridization (FISH) studies using a 5-probe panel on tissue microarrays. Seventy-five cases (40.9%) with confluent PCs were classified as 'PCs-rich' and 108 cases (59.1%) with scattered PCs were classified as 'typical'. Complete FISH data were obtained in 101 cases (55.1%), 79 of which (78.2%) displayed at least one chromosomal aberration. The incidence of each aberration was: 13q-36,7%, 14q32 translocations 30.8%, 11q-24.7%, trisomy 12 19.5% and 17p-15.6%. Five cases showed extra copies of the 14q32 region. The 'PCs-rich' group was associated with 17p-, 14q32/IgH translocation, +12, Ki-67430%. The median survival from the time of tissue biopsy for PCs-rich and typical groups was 11 and 64 months, respectively (P = 0.00001). The PCs-rich pattern was the only predictive factor of an inferior survival at multivariate analysis (P = 0.022). These findings establish an association between cytogenetic profile and the amount of PC in CLL, and show that this histopathologic characteristic is of value for risk assessment in patients with clinically significant adenopathy. Leukemia (2012) 26, 499-508; doi:10.1038/leu.2011.247; published online 23 September 2011