Recent progress in the
Nerve Growth Factor (
NGF) research has shown that this factor acts not only outside its classical domain of the peripheral and central nervous system, but also on non-neuronal and
cancer cells. This latter observation has led to divergent hypothesis about the role of
NGF, its specific distribution pattern within the tissues and its implication in induction as well as progression of
carcinogenesis. Moreover, other recent studies have shown that
NGF has direct clinical relevance in certain human brain
neuron degeneration and a number of human ocular disorders. These studies, by suggesting that
NGF is involved in a plethora of physiological function in health and disease, warrant further investigation regarding the true role of
NGF in
carcinogenesis. Based on our long-lasting experience in the physiopathology of
NGF, we aimed to review previous and recent in vivo and in vitro
NGF studies on
tumor cell induction, progression and arrest. Overall, these studies indicate that the only presence of
NGF is unable to generate cell
carcinogenesis, both in normal neuronal and non-neuronal cells/tissues. However, it cannot be excluded the possibility that the co-expression of
NGF and pro-carcinogenic molecules might open to different consequence. Whether
NGF plays a direct or an indirect role in cell proliferation during
carcinogenesis remains to demonstrate.