 This particular initiation factor binds to the PABPI (PolyA binding protein I), which is in turn binds the messenger RNA's poly(A) tail and eIF3, which is bound to the incoming small ribosomal subunit (40S).eIF4G has been implicated in breast cancer.It appears in increased levels in certain types of breast cancer and increases production of mRNAs that contain IRESs; these mRNAs produce hypoxia- and stress-related proteins that encourage blood vessel invasion (which is important for tumorigenesis).