NGF and hereditary pheochromocytoma-paraganglioma: Interestingly, the increased basal expression and induction of Hsp72 observed in neuron-like SH-SY5Y cells is contrary to the situation of rat pheochromocytoma PC-12 cells differentiated with nerve growth factor which not only showed reduced levels of Hsp72 but also failed to induce Hsp72 upon heat treatment at 42°C for 30 min and 1 h [35].