Plasma TGF-β1-related survival of postmenopausal metastatic breast cancer patients

Abstract

A pilot study was conducted to assess whether plasma levels of transforming growth factor-β (TGF-β1) might facilitate biological subgrouping of postmenopausal metastatic breast cancer patients, and, accordingly, its applicability in clinical oncology. This study included 29 postmenopausal metastatic breast cancer patients. Plasma TGF-β levels were detected by enzyme-linked immunosorbent assay (ELISA). Estrogen and progesterone receptors were assayed by radioligand binding, in accordance with the recommendation of the EORTC. Concentrations of 17-β estradiol were determined by using ELISA-microwell method (DIALAB). Overall survival was followed for 24 months for each individual patient. Stratification of the patients by ER/PR status showed that 14 patients with estrogen receptor-negative, progesterone receptor-negative carcinomas displayed a statistically significant increase in plasma TGF-β levels when compared to plasma TGF-β levels of 6 patients with ER-positive, PR-positive carcinomas (P=0.04). In this study, 7 out of 14 patients with negative receptors’ status had no plasma TGF-β values overlapping with patients having positive receptors’ status. The TGF-β1 cut-off value was defined as the highest plasma TGF-β level of ER-positive, PR-positive patients: 3.28 ng/ml. This plasma TGF-β cut-off value defined low-risk subgroup of 19 patients (≤ 3.28 ng/ml) and high-risk subgroup of 10 patients (>3.28 ng/ml) (P=0.047). Plasma TGF-β1-related survival was independent of the classical prognostic factors of metastatic breast cancer. Accordingly, a clinical significance of elevated plasma TGF-β levels may be suggested.