Histidine decarboxylase and tumour growth

A hamster hepatoma was likewise found to be devoid of histidine decarboxylase activity . 

It has been seen that a specific histidine decarboxylase is present in normal mast cells however, since mitoses are never observed in these cells, it is unlikely that the presence of the enzyme is concerned with growth. Moreover, 

Kahlson, Rosengren and Steinhardt in studies of the Landschutz I tumour growing as isolated, free cells in the mouse peritoneal cavity, have found that on the first day of tumour growth the specific histidine decarboxylase activity is high and correlates with the frequency of tumour cell mitosis. However, it is possible that some of this enzyme activity may have been contributed by the peritoneal mast cells of the host. 

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