BackgroundToll-like receptors (TLRs) have garnered an extraordinary amount of interest in cancer research due to their role in tumor progression. By activating the production of several biological factors, TLRs induce type I interferons and other cytokines, which drive an inflammatory response and activate the adaptive immune system. The aim of this study was to investigate the expression and clinical relevance of TLR3, 4 and 9 in breast cancer.MethodsThe expression levels of TLR3, TLR4 and TLR9 were analyzed on tumors from 74 patients with breast cancer. The analysis was performed by immunohistochemistry.ResultsSamples of carcinomas with recurrence exhibited a significant increase in the mRNA levels of TLR3, TLR4 and TLR9. Tumors showed high expression of TLRs expression levels by cancer cells, especially TLR4 and 9. Nevertheless, a significant percentage of tumors also showed TLR4 expression by mononuclear inflammatory cells (21.6%) and TLR9 expression by fibroblast-like cells (57.5%). Tumors with high TLR3 expression by tumor cell or with high TLR4 expression by mononuclear inflammatory cells were significantly associated with higher probability of metastasis. However, tumours with high TLR9 expression by fibroblast-like cells were associated with low probability of metastasis.ConclusionsThe expression levels of TLR3, TLR4 and TLR9 have clinical interest as indicators of tumor aggressiveness in breast cancer. TLRs may represent therapeutic targets in breast cancer.

Tumors are infiltrated by macrophages, T and B-lymphocytes, which may favor tumor development by promoting angiogenesis, growth and invasion. The aim of this study was to investigate the clinical relevance of the relative amount of macrophages (CD68+), T-cells (CD3+) and B-cells (CD20+) at the invasive front of breast carcinomas, and the expression of matrix metalloproteases (MMPs) and their inhibitors (TIMPs) either at the invasive front or at the tumor center. We performed an immunohistochemical study counting CD3, CD20 and CD68 positive cells at the invasive front, in 102 breast carcinomas. Also, tissue sections were stained with MMP-2, -9, -11, -14 and TIMP-2 antibodies, and immunoreactivity location, percentage of reactive area and intensity were determined at the invasive front and at the tumor center. The results showed that an increased CD68 count and CD68/(CD3+CD20) ratio were directly associated with both MMP-11 and TIMP-2 expression by mononuclear inflammatory cells at the tumor center (p = 0.041 and p = 0.025 for CD68 count and p = 0.001 and p = 0.045 for ratio, respectively for MMP-11 and TIMP-2). In addition, a high CD68/(CD3+CD20) ratio (>0.05) was directly associated with a higher probability of shortened relapse-free survival. Multivariate analysis revealed that CD68/(CD3+CD20) ratio was an independent factor associated with distant relapse-free survival (RR: 2.54, CI: (1.23–5.24), p<0.01). Therefore, CD68/(CD3+CD20) ratio at the invasive front could be used as an important prognostic marker.

An immunohistochemical study was performed using tissue arrays and specific antibodies against MMPs -1, -2, -7, -9, -11, -13, -14, and TIMPs -1, -2 and -3. More than 5,000 determinations on cancer specimens from 124 patients with invasive breast cancer were performed at the center of the tumor and the invasive front. Immunostaining for MMPs/TIMPs by fibroblasts was evaluated. To identify specific groups of tumors with distinct expression profiles, the data obtained from both fibroblast populations were analyzed by unsupervised hierarchical cluster analysis. Intratumor stromal fibroblasts more frequently showed expression of MMP-2, -7, and -14, and TIMP-3, but less frequently of MMP-9 than fibroblasts at the invasive front. Multivariate analysis showed that a high profile of MMPs and TIMPs staining in both fibroblast populations was the most potent predictor factor of distant metastases, whereas a low staining profile in fibroblasts was associated with a low risk of metastases.

Inflammatory conditions may promote tumor progression and aggressiveness. In previous reports, we found a group of breast cancer tumors characterized by metalloprotease-11 (MMP-11) expression by intratumoral mononuclear inflammatory cells (MICs), which was associated with distant metastasis development. Thus, in the present study we evaluated the relationship between MMP-11 expression by MICs, distant metastasis development, and a wide panel of inflammatory factors in breast carcinoma. In an initial approach, we analyzed 65 factors associated with tumor progression and inflammation, in a tumor population classified in good or bad prognosis, based on MMP-11 expression by intratumoral MICs. The most differentially expressed factors were then analyzed in a wider tumor population classified according to MMP-11 expression by MICs and also according to metastasis development. These analyses were carried out by Real-time PCR. The results showed that of the 65 starting factors analyzed, those related with MMP-11 expression by MICs were: IL-1, −5, −6, −8, −17, −18, MMP-1, TIMP-1, ADAM-8, −10, −15, −23, ADAMTS-1, −2, −15, Annexin A2, IFNβ, Claudin-3, CCL-3, MyD88, IRAK-4 and NFκB. Of them, factors more differentially expressed between both groups of tumors were IL-1, IL-5, IL-6, IL-17, IFNβ and NFκB. Thereafter, we confirmed in the wider tumor population, that there is a higher expression of those factors in tumors infiltrated by MMP-11 positive MICs. Altogether these results indicate that tumors developing worse prognosis and identified by MMP-11 expression by intratumoral MICs, shows an up-regulation of inflammatory-related genes.