Histamine in human breast cancer.

Background: Histamine inhibits lymphocyte function in vitro at concentrations of greater than 10(-6) mol/l. The aim of this study was to determine whether histamine concentrations in breast cancers were sufficient to produce an immunological effect.

Methods: Tumour and adjacent normal breast content of histamine was measured using a radioenzymatic assay in 29 patients having surgery for breast cancer.

Results: The median content of histamine in breast cancer tissue was 5.4 (range 0.9-27.3) microg/g (median concentration 4.5 x 10(-5) mol/l), and was significantly greater than that in adjacent breast tissue (P = 0.007).

Conclusion: The concentration of histamine in breast cancer was sufficient to inhibit lymphocyte function and could be locally immunosuppressive.