CA 19-9 monosialoganglioside content of human colorectal tumor cells correlates with tumor cell-induced platelet aggregation

Background: Gangliosides are involved in tumor cell-induced platelet aggregation (TCIPA). CA 19-9 is a monosialoganglioside detected in colon carcinoma cells. Therefore, this study was designed to evaluate whether there was any correlation between the CA 19-9 monosialoganglioside content and TCIPA. Materials and Methods: The CA 19-9 content was determined on gangliosidic extracts of human colorectal tumor cells (GEO, WiDr, DLD-1, MIP) in comparison with the degree of TCIPA. Results: CA 19-9 was detected in all cell lines, except MIP. The mean CA 19-9 content was 10.2, 30.2 and 82.6 U/mu g of sialic acid for GEO, DLD-1 and WiDr, respectively CA 19-9 content directly correlated with TCIPA (p<0.0001). Furthermore, incorporation of exogenous gangliosides in GEO cells resulted in an increase of CA 19-9 content, paralleled by a concomitant increase of TCIPA. Conclusions: The CA 19-9 monosialoganglioside may be involved in platelet/tumor cell interactions thus playing an important role in the haematogenous metastases of colorectal cancer.