https://www.selleckchem.com/products/sp2509.html The protocol consists in the dephosphorylation of the Rb-containing protein lysates by treating them with bovine intestinal phosphatase, followed by assessment of the dephosphorylation by immunoblot.In an era of precision medicine important treatment decisions are dictated by expression of clinically informative tumor protein biomarkers. These biomarkers can be detected by immunohistochemistry (IHC) performed in tumor tissue sections obtained from biopsies or resections. Like all experimental procedures, IHC needs optimization for several of its steps. However, the investigator must avoid optimizing the IHC procedure using valuable human biopsy samples which may be difficult to obtain. Ideally, valuable biopsy samples should only be subjected to IHC once the IHC protocol has been optimized. In this chapter, we describe a procedure for IHC optimization using tri-dimensional (3D) cellular spheroids created from cultured cells. In this approach, cultured cells are pelleted into 3D spheroids, which are then processed just like a tissue sample, namely, fixed, embedded, sectioned, mounted on slides, and stained with IHC just like a human tissue sample. These 3D cellular spheroids have a tissue-like architecture and cellularity resembling a tumor section, and both cellular and antigen structure are preserved. This method is therefore acceptable for IHC optimization before proceeding to the IHC staining of human tumor samples.Antibody selection and optimization are crucial to guarantee accurate and reproducible results when using such antibodies for applications such as western blot analysis and immunohistochemistry (IHC). This is especially important when selecting good candidate antibodies that will be used for cancer immunotherapy diagnostics and research. In this chapter, we describe a Western Blot technique as support methodology for the selection and validation of Programmed Cell Death Ligand 1 (PD-L1) antibodies that c