IFNB1 and cancer: However, the reduced tumorigenic properties in MDA cells after coculture with act hMSCs were partially negated by the IFN-β blockage, which could be due to either (i) the reduced efficacy of the neutralizing antibody over 24 h or (ii) other antitumorigenic factors secreted from act hMSCs during coculture, such as DKK3 as we have shown previously.23 Nevertheless, our result showed that IFN-β is one of the major antitumorigenic factors secreted from act hMSCs by crosstalk with cancer cells.