It is not surprising to see reduced TGFβ-1 levels in mouse sera by these therapeutic adenoviruses since they all express sTGFβRIIFc that can bind TGFβ-1 and neutralize its downstream signaling events via Type II receptors, but the increase of serum GM-CSF levels are also encouraging because many GM-CSF based treatment strategies are currently used in the clinic or hold promise in clinical trials for several cancer types, including breast cancer. Here, TGFB1 is linked to breast cancer.