Immunoblotting of cell lysates confirmed the presence of fast migrating pRB in such cells and accumulation of a pRB species specifically recognised by an antibody for the underphosphorylated active form of pRB, NP-pRB [22] (Figure 2D), indicating that genuine activation of pRB signalling arises in CCT020312-treated cancer cells. Here, RB1 is linked to cancer.