The p27 Kip1 Colorimetric Cell-Based ELISA Kit is a convenient, lysate-free, high throughput and sensitive assay kit that can detect p27Kip1 protein expression profile in cells. The kit can be used for measuring the relative amounts of p27Kip1 in cultured cells as well as screening for the effects that variuos treatments, inhibitors (ie siRNA or chemicals), or activators have on p27Kip1.