The in vitro growth response of primary human colorectal and gastric cancer cells to gastrin.

A series of 31 colorectal and 13 gastric primary human tumours were screened for their growth response to human gastrin-17 in vitro, as assessed by 75Se-seleno-methionine incorporation. Fifty-five percent of colorectal and 69% of gastric tumours showed a significant trophic response to the hormone. The responses were achieved at physiological gastrin concentrations (post-prandial circulating gastrin levels) in 35% of colorectal and 55% of gastric tumours. Lymphocytes from tumour-associated lymph nodes showed no response to the hormone and "normal" mucosal cells (obtained from the resection margin of the surgical specimen) showed lower mean levels of 75Se-seleno-methionine uptake (colorectal: 110%; gastric: 119%, expressed as a percentage of the control) when compared to tumours (colorectal: 151%; gastric: 147%). The small number of well differentiated and/or Dukes' stage A colorectal tumours examined were gastrin-responsive, but all the responsive gastric tumours were poorly differentiated. With respect to ploidy, 89% of diploid and 67% of aneuploid colorectal tumours responded trophically to gastrin. Patients with colorectal or gastric tumours may benefit from treatment with gastrin antagonists.