RAISED ENDOTHELIN-1 LEVELS IN PATIENTS WITH COLORECTAL LIVER METASTASES

Background Endothelin 1 (ET-1), a vasoconstrictor peptide, has been im plicated as a tumour growth stimulator and angiogenesis factor. Method s To assess the involvement of ET-1 in colorectal cancer, immunoelectr on microscopy for ET-1 was performed in colorectal liver metastases an d normal liver (n = 6). ET-1 plasma levels were measured by radioimmun oassay in patients with colorectal cancer, with (n = 18) and without ( n = 12) liver metastases, and in controls (n = 22). Results In normal liver, ET-1 was present in endothelial cells; in tumour, it was observ ed in endothelial cells, tumour cells and myofibroblasts. Mean(s.d.) p lasma ET-1 levels were 2.75 (1.37) pg/ml in controls, 4.53(1.61) pg./m l in patients with colorectal liver metastases (P = 0.001) and 3.92(1. 32) pg/ml in patients without metastases (P = 0.02). Conclusion ET-1 w as present in various cell types within colorectal liver metastases an d raised levels were found in the plasma of patients with colorectal c ancer. ET-1 may not only modulate tumour vascular tone but also act on tumour growth and angiogenesis, both locally and systemically.