Protein tyrosine phosphatases (PTPases) SHP1 and SHP2 are critical regulators in the intracellular signaling pathways that result in cell responses such as mitosis, differentiation, migration, survival, transformation or death. SHP2 is a signal transducer for several receptor tyrosine kinases and cytokine receptors. A novel SHP2 associated glycoprotein was recently cloned from human, rat, mouse and cattle by several labs and was designated SIRPa (1),SHPS1 , MyD1, BIT and p84. SIRPa is a ne