An excellent correlation (90% concordance) was observed between neoplastic B-cell PD-1 immunohistochemistry positivity and molecularly defined CLL/SLL clonal relatedness in DLBCL-RT.
Conversely, alterations in 3/9 microsatellite repeats were detected in one case of Richter's syndrome which had evolved from a pre-existent B-CLL/SLL phase.