ynergistically, for example, GLP-1 and GIP [70] or Tα1 and GM-CSF [71]. Alternatively, the biologically active protein/peptide can be linked via the PAS sequence to a targeting domain such as the arginylglycylaspartic acid peptide RGD peptide which binds to integrins αVβ3 and αVβ5 in order to enhance tumor penetration and accumulation. In