Background

Transforming growth factor (TGF)-b1 has pleiotropic effects in cancer. In the early stages of breast cancer, TGF-b may be responsible for immune tolerance through the activation of T-Regulatory cells (TR). On the other hand, in the late stages of disease, it may induce angiogenic factors [vascular endothelial growth factor (VEGF), interleukin-8 (IL-8) (in Bonnomet J Mammary Gland Biol Neoplasia 2010); and IL-17 (Pickens J Immunol 2010)], and epithelial to mesenchymal transition (EMT) which may lead to an increase in the number of circulating tumor cells (CTC) (Kim, Cell 2009). Therefore, we investigated the possible correlation between TGF-b1, CTC count, angiogenic factors and T-cell function of patients with locally advanced or metastatic breast cancer.

Methods

As an interim analysis of an on-going prospective study, sera and peripheral blood mononuclear cells (PBMC) were collected from breast cancer patients starting a new line of therapy. At analysis, study enrollment included 78 patients with breast cancer [19 with locally advance disease (LABC), 23 with non-metastatic inflammatory breast cancer (IBC), and 32 with metastatic disease (MBC) including 19 with IBC features], and 28 healthy donors (HD). Serum TGF-b1, VEGF, and IL-8 levels were measured by Milliplex Luminex kits (Millipore, Billerica, MA). CD4+CD25+CD127dim TR cells were enumerated in whole blood by FACS (BD Biosciences, San Jose, CA). PBMC were used to study the ability of T cells to synthesize cytokines following activation of the T-cell receptor by immobilized anti-CD3 antibodies. CTC were enumerated by CellSearch (Veridex, Raritan,

NJ). The Spearman Rho was calculated for nonparametric correlations and the Mann-Whitney U test was used to determine significant differences between median values.

Results

LABC patients and HD had a median serum TGF-b1 that was significantly higher than that of MBC patients (P = 0.042). There were statistically significantly positive correlations between serum TGF-b1 and the number of CD4+ T cells (rho = .226, P = .029) and IL-10 produced by %CD4+ (rho = .388, P = .002) and %CD8+ (rho = .459, P < .001) T cells. Furthermore, there was a positive correlation between serum TGF-b1 and the % of CD8+, but not CD4+, T cells that produced IL-17 (rho = .250, P = .022). Serum TGF-b1 levels did not correlate with either % or number of TR cells. Although serum TGF-b1 level of MBC patients was independent of CTCs (24.4 ng/mL vs. 24.0 ng/mL, P = .317), MBC patients with CTC had significantly higher serum levels of angiogenic factors such as VEGF (530 ng/mL vs. 240 ng/mL, P=0.037) and IL-8 (45.6 pg/ml vs. 20.0 pg/ml P= .006) than those of patients with no CTC. Even so, MBC patients with or without CTC have similar % of CD4 and CD8 T-cell subsets that could be activated to produce IFN-g, IL-2, TNF-a, IL-17, or IL-10. Conclusion:

The concomitant presence of elevated serum TGF-ß1 levels and IL-10 producing T cells suggest immune suppression could facilitate disease progression of breast cancer. T-cell function is independent of CTC in MBC patients; however, serum VEGF and IL-8 levels were significantly elevated in MBC patients with CTC suggesting that vascular changes can facilitate tumor dissemination.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P3-02-07.