HISTAMINE CONTENT IN COLORECTAL-CANCER - ARE THERE SUFFICIENT LEVELS OF HISTAMINE TO AFFECT LYMPHOCYTE FUNCTION

Histamine has been found to stimulate growth of colorectal cancer in v itro and ill vivo. Histamine has also been found to inhibit lymphocyte activity ill vitro at concentrations greater than 10(-7) M. The aim o f our study was to determine if the histamine concentrations in human colorectal cancer mere sufficient to achieve these effects. We measure d the histamine content in 31 colorectal cancer specimens using a radi oenzymatic assay. Results were expressed as mu g histamine per gram of fresh tissue weight, Recovery and reproducibility studies were also c arried out. The median histamine concentration in colorectal cancer ti ssue mas 8.4 mu g/g [7.6 x 10(-5) M], ranging from 0.3 mu g/g to 20.6 mu g/g. The high concentration of histamine in colon cancer is enough to be locally immunosuppressive.