Immunohistochemical patterns of Bcl11A expression in classical Hodgkin lymphoma and correlations with survival. (A,B) The usual pattern of BCL11A positivity in cHL tissues. The immunostaining is located mainly in the nucleus of reactive small lymphocytes surrounding Reed-Sternberg cells (arrows). Variable numbers of positive plasmacytoid dendritic cells were also observed. The number of positive reactive cells scored as high/score 3 or low/score 1 (A and B, respectively) was strongly correlated with EFS in the whole population of 143 informative patients (different from those analyzed by DNA microarrays), as shown by Kaplan-Meier estimates (D). Among these patients, Bcl11A positivity has also a significant prognostic value in the subgroup of patients with an international prognostic score of 2 or less (E) and in patients with an IPS more than 2 (F) as shown by Kaplan-Meier estimates of EFS. Panel C illustrates an infrequent pattern of Bcl11A expression in cHL tissues, with a positive signal located in neoplastic Reed-Sternberg cells (). This latter pattern was not statistically correlated with survival. Panels A-C correspond to a 40×/0.75 objective lens (×400 magnification).