Tumor epithelial cells (TEpCs) and spindle-shaped stromal cells, not associated with the vasculature, of patients with early breast cancer express osteoprotegerin (OPG), tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), receptor activator of nuclear factor kappa B ligand, stromal cell derived factor-1, interleukin-6, macrophage colony stimulating factor, chemokine (C-C motif) ligand-2 (CCL-2) and their receptors at significantly higher levels compared with non-neoplastic breast tissues. We evaluated the clinicopathological significance of these ligands and receptors in TEpC and spindle-shaped stromal cells, not associated with the vasculature, to determine their impact on prognosis of patients with early-stage breast cancer. We conducted immunohistochemical analyses of protein expression in primary tumors of patients with early breast cancer and analyzed their association with standard prognostic parameters and clinical outcomes, including local relapse, metastatic recurrence, disease-free survival (DFS), metastasis-free survival (MFS), and overall survival (OS). Elevated levels of TRAIL-R3 and chemokine (C-C motif) receptor 2 (CCR-2) in TEpCs and OPG and CCL-2 in stromal cells were significantly associated with a higher risk of metastasis (p = 0.032, p = 0.003, p = 0.038, and p = 0.049; respectively). Moreover, high expression of TRAIL-R3 and CCR-2 in TEpCs was associated with shorter DFS, MFS, and OS. High TRAIL-R3 expression in TEpCs was an independent prognostic factor for DFS and OS, and high CCR-2 expression in these cells was an independent prognostic factor for MFS. High levels of TRAIL-R3 and CCR-2 expression in TEpCs identified patients with early breast cancer with poor outcomes.

Introduction: Bone metastasis is one of the causes that mainly decrease survival in patients with advanced breast cancer. Therefore, it is essential to find prognostic markers for the occurrence of this type of metastasis during the early stage of the disease. Currently, cancer-associated fibroblasts, which represent 80% of the fibroblasts present in the tumor microenvironment, are an interesting target for studying new biomarkers and developing alternative therapies. This study evaluated the prognostic significance of the CD105 expression in cancer-associated fibroblasts in early breast cancer patients.Methods: Immunohistochemistry was used to assess CD105 expression in invasive ductal breast carcinomas (n = 342), analyzing its association with clinical and pathological characteristics.Results: High CD105 expression in cancer-associated fibroblasts was associated with an increased risk of metastatic occurrence (p = 0.0003), particularly bone metastasis (p = 0.0005). Furthermore, high CD105 expression was associated with shorter metastasis-free survival, bone metastasis-free survival, and overall survival (p = 0.0002, 0.0006, and 0.0002, respectively). CD105 expression also constituted an independent prognostic factor for metastasis-free survival, bone metastasis-free survival, and overall survival (p = 0.0003, 0.0006, and 0.0001, respectively).Discussion: The high CD105 expression in cancer-associated fibroblasts is an independent prognostic marker for bone metastasis in early breast cancer patients. Therefore, the evaluation of CD105(+) CAFs could be crucial to stratify BCPs based on their individual risk profile for the development of BM, enhancing treatment strategies and outcomes.

Bone metastasis is a leading cause of reduced survival in patients with advanced breast cancer. Therefore, identifying prognostic markers for bone metastasis at early disease stages is crucial. Microcalcifications are common findings in mammographic imaging and often serve as early diagnostic indicators. Certain types of microcalcifications have been linked to unfavorable genetic and molecular tumor profiles and are associated with poor prognosis. In particular, calcifications located within large ducts—such as casting-type, duct-centric patterns—have been described as independent markers of adverse outcome when compared to tumors with other calcification types or without calcifications. This study evaluated the prognostic significance of anarchic microcalcifications, defined as calcifications with irregular borders and/or disorganized patterns, in patients with early-stage breast cancer. Hematoxylin and eosin staining was used to assess the presence of these microcalcifications in invasive ductal carcinoma samples (n = 350). Their association with clinical and pathological characteristics was analyzed, including local relapse and bone metastasis occurrence. The presence of tumor microcalcifications was significantly associated with an increased risk of local relapse (p = 0.0360) and bone metastasis (p = 0.0020). Moreover, patients with microcalcifications exhibited shorter local relapse-free survival and bone metastasis-free survival (p = 0.0080 and p = 0.0020, respectively). Importantly, multivariate analysis confirmed that microcalcifications were an independent prognostic factor for both outcomes (p = 0.0150 and p = 0.0020, respectively). These findings suggest that the presence of tumor microcalcifications may serve as an independent prognostic marker for bone metastasis in early-stage breast cancer. Incorporating the evaluation of microcalcifications into routine pathological assessments could improve prognostic precision and support personalized treatment strategies. Further research is needed to elucidate the molecular mechanisms underlying the association between tumor microcalcifications and breast cancer progression.

BACKGROUND: The molecular system of receptor activator of nuclear factor kappa- β (RANK) and its ligand (RANKL) plays a role in a variety of physiological and pathological processes. These encompass the regulation of bone metabolism, mammary gland development, immune function, as well as their involvement and tumorigenesis. Nevertheless, limited knowledge exists regarding their function within the tumor microenvironment. METHODS AND RESULTS: We explored the significance of RANK expression in cancer-associated fibroblasts (CAFs) as a prognostic biomarker in early breast cancer patients (BCPs) by immunohistochemistry. Results reveal a significant correlation between high RANK expression in CAFs and an increased risk of metastasis ( p = 0.006), shorter metastasis-free survival (MFS) [ p = 0.007, OR (95%CI) = 2.290 (1.259–4.156)], and lower overall survival (OS) [ p = 0.004, OR (95%CI) = 2.469 (1.343–4.541)]. Upon analyzing the phenotype of CD34(-) CAFs isolated from primary tumors in BCPs, we observed co-expression of RANK with CD105 marker by immunofluorescence and flow cytometry, characteristic of mesenchymal stem/stromal cells (MSCs), suggesting the possible cellular origin. Also RANKL-RANK system increase the OCT-4, SOX-2 and DKK-1 (dickkopf 1) gene expression in CD34(-) CAFs by RT-PCR. Moreover, this system plays a crucial role in the migration of these CD34(-) CAFs. CONCLUSIONS: These results support the clinical relevance of RANK in CAFs and propose its potential as a future therapeutic target in the treatment of early BCPs.

Purpose: Cancer-associated fibroblasts (CAFs) are highly heterogeneous and critically influence breast cancer progression, yet functionally relevant stromal subpopulations remain poorly defined. This study investigates whether CD105 expression distinguishes fibroblast subsets with distinct mesenchymal stem–like properties and tumor-modulating functions within early-stage breast cancer. Methods: CD105(+)/CD34(-) and CD105(-)/CD34(-) fibroblast subpopulations were isolated from primary luminal breast tumors and analyzed for phenotypic, molecular, and functional characteristics, as well as for their effects on breast cancer cell behavior using in vitro assays, including conditioned media (CM) approaches. Results: Both fibroblast subpopulations displayed mesenchymal stem/stromal cell (MSC) characteristics; however, CD105(+)/CD34(-) fibroblasts displayed a more pronounced MSC–like phenotype, with enhanced proliferative capacity, altered oxidative status, and a distinct gene expression and secretory profile. CM from CD105(+)/CD34(-) fibroblasts more strongly promoted migration and proliferation and increased the expression of genes associated with stemness, osteogenic differentiation, bone mineralization, and osteoclastogenesis in luminal and triple-negative human breast cancer cell lines, compared with CM from CD105(-)/CD34(-) fibroblasts. Conclusion: These findings identify CD105 as a potential functional discriminator of breast CAF subpopulations and suggest that CD105(+) fibroblasts may preferentially support tumor progression and the acquisition of bone-related traits. This work provides new insight into CAF heterogeneity and its potential relevance for metastatic progression, and may also guide future therapeutic strategies and research directions.