On 2014 Aug 07, Madhusudana Girija Sanal commented:

This is an interesting observation. There is another aspect. It is known that platelets carry serotonin and they play an important role in distributing extra-neural serotonin.Platelet depletion impairs liver regeneration. Lesurtel M et al reported in 2006 that platelet-derived serotonin mediates liver regeneration (Science. 2006 Apr 7;312(5770):104-7.). Another paper by Paulose and others, back in 1998 reported increased mitotic activity in liver cells in-vitro in response to serotonin. (Hepatology. 1998 Jan;27(1):62-6.). It is therefore possible that platelets may play a role in hepatocellular carcinoma-proliferation and metastasis. Thus, serotonin may have an additional role different from the growth factors such as PDGF in liver cancer secreted by platelets. However, I doubt if this has some direct clinical implication in the management of this cancer considering its extremely dynamic nature.

On 2014 Aug 07, Madhusudana Girija Sanal commented:

This is an interesting observation. There is another aspect. It is known that platelets carry serotonin and they play an important role in distributing extra-neural serotonin.Platelet depletion impairs liver regeneration. Lesurtel M et al reported in 2006 that platelet-derived serotonin mediates liver regeneration (Science. 2006 Apr 7;312(5770):104-7.). Another paper by Paulose and others, back in 1998 reported increased mitotic activity in liver cells in-vitro in response to serotonin. (Hepatology. 1998 Jan;27(1):62-6.). It is therefore possible that platelets may play a role in hepatocellular carcinoma-proliferation and metastasis. Thus, serotonin may have an additional role different from the growth factors such as PDGF in liver cancer secreted by platelets. However, I doubt if this has some direct clinical implication in the management of this cancer considering its extremely dynamic nature.