Changes in histamine synthesis, tissue content and catabolism in human breast cancer

The present study in 10 breast cancer patients supports the concept that newly synthetized, nascent histamine is involved in tumour growth. Histidine decarboxylase (HDC) activity is increased in mammary tumour tissue compared to healthy mammary gland-, skin- and muscle tissue in all but one patient studied. The newly formed histamine is probably not stored in the tumour tissue. Significantly decreased histamine concentrations were measured in parallel samples in the tumour tissue. Moreover, the preliminary results from urinary analysis of histamine and N tau-methylhistamine in 3 of the 10 patients studied showed a significant decline after tumour extirpation compared to preoperative values.