Trefoil factor 1 as a predictive factor of bone metastases in breast cancer.

Abstract

11022 Background: Patients with breast cancer frequently develop bone metastases, which are responsible for high morbidity and reduced quality of life. The early identification of patients with a high probability of relapsing in this site could be used to select candidates for tailored therapy with bone-specific drugs such as bisphosphonates or RANK-L inhibitors. We aimed to identify a pattern of tissue markers in primary breast cancer that could predict bone metastatization. Methods: Expression of different markers was retrospectively analyzed in frozen breast cancer tissue samples from 90 patients comprising 30 cases with no evidence of disease (NEDP), 30 with bone metastases (BMP) and 30 with visceral metastases (VMP). Eight transcripts were analyzed by Quantitative Real time PCR: trefoil factor 1(TFF1), bone sialoprotein (IBSP), heparanase (HPSE), secreted protein acidic and rich in cysteine (SPARC), connective tissue growth factoe (CTGF), B2 microglobulin (B2M) and receptor activator of Nf-kB (RANK). Immunohistochemistry of TFF1 was performed on a part of the case series. Results: Marker expression analysis in the 3 different subgroups showed at least twofold higher median values of all markers in NEDP and VMP subgroups than in BMP. In particular, TFF1, B2M and CXCR4 levels showed statistically significant values. Median TFF1 value in BMP patients was 430.64 compared to 115.83 and 32.79 in VMP and NEDP, respectively (p=0.0043). Considering markers as dichotomous variables, TFF1 expression in BMP reached 59% compared to 21% and 23 % in NEDP and VMP, respectively (p=0.0022). Univariate analysis confirmed that TFF1 predicted the relapse and also the site of relapse. Immunohistochemistry data on TFF1 revealed that this protein was expressed only by cancer cells. Furthermore, the accuracy of the marker did not change at RNA or protein level, thus excluding a post transcriptional control of the RNA. Conclusions: In this preliminary study we identified a gene expression pattern in primary breast cancer that can identify patients destined to relapse to the bone. In particular, TFF1 would seem to be a suitable marker for bone metastatization and a possible target for the development of new drugs.