FOS and breast carcinoma: It was reported that AP-1 (FOS and JUN) transcription factor is critical for the growth and proliferation of breast cancer cells47 and is also involved in the stimulation of NF-κβ transactivation activity.48 In erythroid cells, Epo was reported to co- or posttranslationally increase AP-1 activity.49 We therefore performed rHuEpo treatment of MCF-7 and MDA-MB-231 cells in order to assess the effect of rHuEpo treatment on cell proliferation and its potential to synergize with cDDP in suppression of breast cancer cell growth.