Aiming at a potential tumor-promoting effect of Pgrn at the cellular level which was recently reported in cholangiocarcinoma [23] and prostate cancer cells [15] we assessed the viability and number of CLL cells cultured for two to five days in the absence or presence of different concentrations (10–1000 ng/ml) of recombinant Pgrn. Here, GRN is linked to prostate cancer.