EFFECT OF MAST-CELL PRODUCTS AND HISTAMINE ON THE PROLIFERATIVE BEHAVIOR OF HUMAN-MELANOMA AND CARCINOMA-CELLS INVITRO

The functional importance of mast cells in modifying tumour cell behav iour has long been recognised and recent evidence suggests that mast c ell: tumour interactions contribute to the growth and development of s pecific cancers. We have used in vitro studies to examine such interac tions in relation to tumour cell proliferation. Soluble mast cell prod ucts (MCP) were prepared from Furth mastocytoma cells at 10(6) cells/m l. The addition of MCP (10% v/v) to cultures of human melanoma cells ( SK23 and DX3.LT5.1), breast carcinoma cells (8701-BC) and normal skin fibroblasts resulted in increased rates of cell proliferation. Althoug h histamine H-2 receptors are expressed by the melanoma cells, the add ition of exogenous histamine (5 and 25 muM) had no effect on the proli ferative rate of the human melanoma cell lines, or on carcinoma cells derived from breast and prostate. The data indicate that exogenous his tamine was not mitogenic for three tumour cell cultures and that other factors derived from mast cells appear to be essential for the increa sed proliferative response.