In situ localization of tumor cells associated with the epithelial-mesenchymal transition marker Snail and the prognostic impact of lymphocytes in the tumor microenvironment in invasive ductal breast cancer

Cancer Stem Cells and Circulatory Tumor Cells Promote Breast Cancer Metastasis

Breast cancer (BC) is a highly metastatic, pathological cancer that significantly affects women worldwide. The mortality rate of BC is related to its heterogeneity, aggressive phenotype, and metastasis. Recent studies have highlighted that the tumor microenvironment (TME) is critical for the interplay between metastasis mediators in BC. BC stem cells, tumor-derived exosomes, circulatory tumor cells (CTCs), and signaling pathways dynamically remodel the TME and promote metastasis. This review examines the cellular and molecular mechanisms governing the epithelial to mesenchymal transition (EMT) that facilitate metastasis. This review also discusses the role of cancer stem cells (CSCs), tumor-derived exosomes, and CTs in promoting BC metastasis. Furthermore, the review emphasizes major signaling pathways that mediate metastasis in BC. Finally, the interplay among CSCs, exosomes, and CTCs in mediating metastasis have been highlighted. Therefore, understanding the molecular cues that mediate the association of CSCs, exosomes, and CTCs in TME helps to optimize systemic therapy to target metastatic BC.

Exosomes and Their Role in Cancer Progression

Exosomes from extracellular vesicles can activate or inhibit various signaling pathways by transporting proteins, lipids, nucleic acids and other substances to recipient cells. In addition, exosomes are considered to be involved in the development and progression of tumors from different tissue sources in numerous ways, including remodeling of the tumor microenvironment, promoting angiogenesis, metastasis, and invasion, and regulating the immune escape of tumor cells. However, the precise molecular mechanisms by which exosomes participate in these different processes remains unclear. In this review, we describe the research progress of tumor cell-derived exosomes in cancer progression. We also discuss the prospects of the application of exosomes combined with nanoengineered chemotherapeutic drugs in the treatment of cancer.

Mesenchymal Stem Cells, Immune Cells and Tumor Cells Crosstalk: A Sinister Triangle in the Tumor Microenvironment

Mesenchymal Stem Cells [MSCs] are a heterogeneous population of fibroblast-like cells which maintain self-renewability and pluripotency. Many studies have demonstrated the immunomodulatory effects of MSCs on the innate and adaptive immune cells. As a result of interactions with tumor cells, microenvironment and immune-stimulating milieu, MSCs contribute to tumor progression by several mechanisms, including sustained proliferative signal in cancer stem cells [CSCs], inhibition of tumor cell apoptosis, transition to tumor-associated fibroblasts [TAFs], promotion of angiogenesis, stimulation of epithelial-mesenchymal transition [EMT], suppression of immune responses, and consequential promotion of tumor metastasis. Here, we present an overview of the latest findings on Janusfaced roles that MSCs play in the tumor microenvironment [TME], with a concise focus on innate and adaptive immune responses.

A simple technique to construct tissue macroarrays

AIMS

In the diagnostic or research field, there is a need that the histopathological evaluation provides as much information as possible, with the shortest time and lowest cost. The development of the tissue microarray (TMA) technology has significantly facilitated and accelerated studies with tissue analyses using in situ technologies. Nevertheless, one of the most recognised limitations of TMA is that the small cores used to construct a TMA may not accurately represent characteristics of the whole tissue specimen. The aim is to present the technical aspects of a simple system to construct tissue macroarrays (TMaAs), its advantages and limitations, and some results of its use in for research purposes.

METHODS

The study presents three possibilities of preparing the specimens with up to 6 mm diameter to be included into the TMaA paraffin block using our method.

RESULTS

With this technique, it was possible to obtain glass slides with multiple whole fragments, which were used in five different studies.

CONCLUSIONS

We presented a method for construction of multi-TMaA paraffin blocks, which is very simple for optimising laboratory techniques requiring paraffin-embedded tissue sections and can be easily implemented in any institution with a histology laboratory.

Morphological Evaluation of Tumor-Infiltrating Lymphocytes (TILs) to Investigate Invasive Breast Cancer Immunogenicity, Reveal Lymphocytic Networks and Help Relapse Prediction: A Retrospective Study

Tumor-infiltrating lymphocytes (TILs) in breast cancer are a key representative of the tumor immune microenvironment and have been shown to provide prognostic and predictive biomarkers. The extent of lymphocytic infiltration in tumor tissues can be assessed by evaluating hematoxylin and eosin (H&E)-stained tumor sections. We investigated tissue microarrays of 31 invasive breast cancer patients, looking at quantity and topological distribution of CD3+, CD8+, CD20+, Ki67+, FoxP3+ TILs and CD3+/FoxP3+, CD8+/FoxP3+ cell ratios. We separately evaluated TILs at the invasive edge and at the center of the tumor, to find any clinical implications of tumor heterogeneity. No statistically significant difference was found in quantity and distribution of both TIL subsets and TIL ratios, by comparing patients who suffered from a local or distant recurrence of the tumor (relapse group: 13 patients) with patients not showing cancer relapse (non-relapse group: 18 patients). In the whole sample, we observed three main statistically significant positive correlations: (1) between CD3+ and CD8+ T-cells; (2) between FoxP3+ and Ki67+ lymphocyte infiltration; (3) between CD3+/FoxP3+ cell ratio (C3FR) and CD8+/FoxP3+ cell ratio (C8FR). Tumor heterogeneity and stronger positive TIL associations were found in the non-relapse group, where both CD3-CD8 and FoxP3-Ki67 inter-correlations were found to be significant at the center of the tumor, while the correlation between C3FR and C8FR was significant at the invasive edge. No correlations between TIL subsets were detected in the relapse group. Our findings suggest the existence of stronger inter-subtype lymphocytic networks in invasive breast cancer not showing recurrence. Further evaluations of clinical and topological correlations between and within TIL subsets are needed, in addition to the assessment of TIL quantification and distribution, in order to follow up on whether morphological evaluation of TILs might reveal the underlying lymphocytic functional connectivity and help relapse prediction.