ASS1 and breast cancer: The BxPC-3 (primary pancreatic cancer), SW1990 (spleen metastatic pancreatic cancer), BT474 (breast cancer), and HepG2 (HCC) cells expressed high levels of ASS mRNA and the PANC-1 (primary pancreatic cancer), MIA PaCa-2 (primary pancreatic cancer), and MDA-MB-231 (breast cancer) cells expressed low levels of ASS relative to MCF-7 cells (Figure 1A).