Soluble type III TGFβ receptor in diagnosis and follow-up of patients with breast cancer

Type III transforming growth factor (TGF) receptor (TGFrIII) modulates TGF superfamily signaling. Its tumor tissue expression is downregulated in human breast cancer. We determined (indirect ELISA) plasma levels of the soluble receptor (sTGFrIII) in 47 women with breast cancer (AJCC stages 0-IIB) (cases) pre-surgery and over two months after the surgery, and in 36 healthy women (controls). Plasma sTBFrIII was lower in cases than in the controls (age-adjusted difference -29.7ng/mL, p<0.001), and discriminated between disease and health (sensitivity and specificity 100% at 16.6ng/mL). With adjustment for age, AJCC stage, lymph node involvement, HER2 and hormone receptor status, higher pre-surgery sTBFrIII was associated with better progression-free survival (HR=0.68, 95%CI 0.49-0.89, p=0.004). An increasing trend in plasma sTBFrIII was observed over 2 months after the surgery (0.6% increase/day, p<0.001), consistently across the patient subsets. Data suggest a high potential of plasma sTBFrIII as a novel diagnostic and prognostic biomarker in breast cancer.