Protein S in cancer patients with non-metastatic solid tumors

AIMS: To study protein S, as an acute phase protein, for its relationships with C4b-BP (C4BP), fibrinogen and Factor VIII:C in a group of patients with solid tumours, without proven metastases. METHODS: Eighty-one consecutive patients with gastrointestinal or pelvic adenocarcinoma (TNM staging: T1-3, N0-2, M0) and 58 healthy subjects were evaluated for plasma free and total protein S antigen, protein S activity, C4BP, fibrinogen and Factor VIII:C. RESULTS: When compared to the control group, the total protein S, the C4BP, the fibrinogen and the Factor VIII:C mean levels were significantly higher in the cancer group, but there was no significant difference for the free and the functional protein S mean concentrations. In both groups the free protein S was correlated with the functional and the total protein S; moreover the latter was significantly correlated with the C4BP, whereas it was significantly correlated with the fibrinogen and the Factor VIII:C only in the cancer group. In addition, a high correlation was found among the C4BP, the fibrinogen and the Factor VIII:C. CONCLUSIONS: Our data show that in these patients there is an acute phase response and suggest that, in the thrombophilic early cancer screening, determination of free protein S is redundant.