The beta-glucans (beta-G) are polysaccharides produced by various organisms, and sulfation of beta-G renders them more soluble. With the objective to assess the effects of sulfated and non-sulfated beta-G extracted from Agaricus brasiliensis in MCF-7 cells, assays were used to evaluate cytotoxicity, genotoxicity, cell proliferation and mRNA expression. The sulfated and non-sulfated beta-G showed dose-dependent cytotoxicity at concentrations of 5 and 10 mu g/mL, by the MTT assay. However, only cytotoxicity was observed after 24h by the Red Neutral test for sulfated beta-G, with no genotoxicity for either beta-G in comet assay. Proliferation was decreased only at 72h at a concentration of 100 mu g/mL of sulfated beta-G. Treatment with 5 mu g/mL of sulfated beta-G for 6h reduced the expression of pro-apoptotic genes and stress signaling genes, cell cycle arrest, damage and cell migration. The 5 mu g/mL of non-sulfated beta-G for 6h reduced the expression of the stress response gene and signaling damage. These results indicate that the cytotoxicity in the MTT is not cell death, and that, in general, sulfated beta-G have greater cytotoxicity compared to non-sulfated beta-G.