FAS and breast cancer: The spectrophotometric assay was commonly used to determine the purity of FAS activity during isolation of the enzyme from tissues, such as rabbit mammary gland [70,160], lamb [148], mouse [155], or human [171,172] AT, human [164] or rat [161,173] liver or from cell lines, such as 3T3-F442A [167], BT474, MCF-7, MDA-MB-231 breast cancer cells [168], human adipocytes [170] or HEK293T, HCT116, and ZR-75-30 [169].