PLK1 and acute lymphoblastic leukemia: Additionally, a quantitative phosphoproteomic comparison of T-ALL PDXs treated with a BCL2 inhibitor or vehicle control revealed several proteins (Fig. 3C), such as Nucleolin (NCL) and Intraflagellar Transport 81 (IFT81, also known as ICE1), which have been reported as PLK1 substrates [40–43].