 
              Genistein
      Genistein, a phytoestrogen found in soy products, is a highly specific inhibitor of protein tyrosine kinase (PTK)  which blocks the mitogenic effect mediated by EGF on NIH-3T3 cells with IC50 of 12?M or by insulin with IC50 of 19 ?M. 
    
    
      
    
   
               
             
             
             
            