This characterises TrkAIII SH-SY5Y cells as type I tumour cells, sensitive to TRAIL-induced apoptosis through the extrinsic pathway [14, 19, 20, 25], with the intrinsic pathway blocked by constitutive Bcl-2, Bcl-xL and Mcl-1 expression (this study and 49). The gene discussed is BCL2; the disease is neoplasm.