Tissue factor expression as a possible determinant of thromboembolism in ovarian cancer

Abstract

Ovarian cancer, and clear cell carcinoma in particular, reportedly increases the risk of venous thromboembolism (VTE). However, the mechanisms remain unclear. Tissue factor (TF) supposedly represents a major factor in the procoagulant activities of cancer cells. The present study examined the involvement of TF expression in VTE for patients with ovarian cancer. Subjects comprised 32 consecutive patients (mean age 49.8 years) with histologically confirmed ovarian cancer. Presence of VTE was examined using a combination of clinical features, D-dimer levels and venous ultrasonography. Immunohistochemical analysis was used to evaluate TF expression into 4 degrees. Venous thromboembolism was identified in 10 of the 32 patients (31%), including five of the 11 patients with clear cell carcinoma. Tissue factor expression was detected in cancer tissues from 24 patients and displayed significant correlations with VTE development (P=0.0003), D-dimer concentration (P=0.003) and clear cell carcinoma (P<0.05). Multivariate analysis identified TF expression as an independent predictive factor of VTE development (P<0.05). Tissue factor (TF) expression is a possible determinant of VTE development in ovarian cancer. In particular, clear cell carcinoma may produce excessive levels of TF and is more likely to develop VTE.

Figure 1

Immunohistochemical staining of tissue factor in ovarian carcinoma tissues. (A) Negative control, (−); (B) weakly positive (<50% positive tumour cells), (+); (C) moderately positive (⩾50% positive tumour cells with weak intensity), (++); (D) strongly positive (⩾50% positive tumour cells with strong intensity), (+++), based on the proportion of the entire tumour cell population positive for TF. All pictures were taken at original magnification × 200.