Blocking antibody against the follistatin protein results in an increased tumor proliferation. Co-cultures of tumor N29 (A) and N32 (B) together with irradiated NPC (HiB5/ST14A), were treated by adding an antibody targeting the follistatin protein. Cells were seeded together and allowed to attach before addition of the antibodies. The plates were pulsed with 3H-thymidine after 3 days in culture and cell division was measured as the amount of incorporated 3H-thymidine. White bars show the proliferation of NPC + tumor control cultures and black bars show the proliferation after the addition of follistatin antibody. Mean ± stdev: Statistical analysis was made using t-test and Mann Whitney Wilcoxon rank sum test * P < 0.05.