[In vitro effect of culture fluids from neoplastic tissues on platelet aggregation. I. Human tumors of the gastrointestinal tract].

The effects on platelet function of culture media from 7 human tumours of the gastroenteric tract have been studied on platelet rich plasma obtained from 28 apparently normal subjects. Platelet aggregation was investigated according to Born's method. Some of the culture media showed an aggregating activity on platelets, while others did not; after dialysis, however, also the last ones aggregated platelets. Furthermore all the media both before and after dialysis were able to increase the platelet response to low doses of ADP (3 microM), and these effects were inhibited by Aspirin (0,1 mM). These results suggest that the tumours investigated release stimulating activities on platelet function and that these interactions can be inhibited pharmacologically.