SAG and breast cancer: While the DBA/2 derived Eb T lymphoma cells did not express this SAG, the spontaneous metastatic variant ESb and its adhesion variant ESb-MP expressed endogenous mouse mammary tumour provirus (Mtv)- typical intracisternal A-particles (IAP), Mtv7 orf/SAG message and vSAG7 protein at the cell surface (Schirrmacher et al, 2000).