Heterogeneity of Stemlike Circulating Tumor Cells in Invasive Breast Cancer.

The presence of stem and epithelial-mesenchymal-transition (EMT) features in circulating tumor cells (CTCs) determines their invasiveness, adaptability to the microenvironment, and resistance to proapoptotic signals and chemotherapy. It also allows them to fulfil the role of metastatic "seeds". We evaluated the heterogeneity of stem CTCs by their CD44, ALDH1, and CD133 expression depending on N-cadherin expression in breast-cancer patients. A total of 38 female patients were selected for this study. CTC phenotypes were determined by flow cytometry before any type of treatment. Multiplex immunofluorescence was used for the evaluation of tumor-cell heterogeneity in primary lesions. In patients who had CD44-CD24- CTCs, a subset of cells with the expression of other stem-cell markers (CD133 and ALDH1) were detected. Expression of CD133 and/or ALDH1 may be associated with expression of N-cadherin: all populations of N-cadherin+ CTCs demonstrate stem features; in the absence of N-cadherin expression, true nonstem (CD44-CD24-CD133-ALDH1-) cells are found. The heterogeneity of stem marker expression in CTCs was observed regardless of N-cadherin expression. In our study, stromal cell-derived factor-1 (SDF-1) receptor expression in CTCs did not depend on stemlike traits, but was instead associated with N-cadherin expression. Subpopulations of tumor cells, detected both in tumors and blood, were identified. Breast cancer was characterized by pronounced interpersonal and intrapersonal heterogeneity of CTCs by the presence and combination of various stem features and N-cadherin expression. To complete the characterization of stemlike features of CTCs, we suggest the simultaneous use of the three stem markers.

Genome-wide methylotyping resolves breast cancer epigenetic heterogeneity and suggests novel therapeutic perspectives.

Aim: To provide a breast cancer (BC) methylotype classification by genome-wide CpG islands bisulfite DNA sequencing. Materials & methods: XmaI-reduced representation bisulfite sequencing DNA methylation sequencing method was used to profile DNA methylation of 110 BC samples and 6 normal breast samples. Intrinsic DNA methylation BC subtypes were elicited by unsupervised hierarchical cluster analysis, and cluster-specific differentially methylated genes were identified. Results & conclusion: Overall, six distinct BC methylotypes were identified. BC cell lines constitute a separate group extremely highly methylated at the CpG islands. In turn, primary BC samples segregate into two major subtypes, highly and moderately methylated. Highly and moderately methylated superclusters, each incorporate three distinct epigenomic BC clusters with specific features, suggesting novel perspectives for personalized therapy.

Heterogeneity of Circulating Tumor Cells in Neoadjuvant Chemotherapy of Breast Cancer.

The biological properties of circulating tumor cells (CTCs), and their dynamics during neoadjuvant chemotherapy are important, both for disease progression prediction and therapeutic target determination, with the aim of preventing disease progression. The aim of our study was to estimate of different CTC subsets in breast cancer during the NACT (neoadjuvant chemotherapy). The prospective study includes 27 patients with invasive breast cancer, T2-4N0-3M0, aged 32 to 60 years. Venous heparinized blood samples, taken before and after biopsy, after each courses of chemotherapy (on days 3-7), and before surgical intervention, served as the material for this study. Different subsets of circulating tumor cells were determined on the basis of the expression of EpCAM, CD45, CD44, CD24, and N-Cadherin using flow cytometry. As the result of this study, it has been observed that significant changes in the quantity of the different subsets of circulating tumor cells in patients' blood were observed after carrying out the 3rd course of NACT. NACT causes significant changes in the quantity of six CTC subsets, with various combinations of stemness and epithelial-mesenchymal transition (EMT) properties.

Relationship between the expression of phosphorylated heat shock protein beta-1 with lymph node metastases of breast cancer.

BACKGROUND: Heat shock protein beta-1 (HspB1) is a chaperone of the sHsp (small heat shock protein). The common functions of sHsps are chaperone activity, inhibition of apoptosis, regulation of cell development, and cell differentiation, take part in signal transduction. OBJECTIVE: To study the intracellular localization of phosphorylated features and non-phosphorylated forms of HspB1 in primary breast cancer cells and to evaluate their relationship with regional lymphatic metastasis. MATERIAL AND METHODS: Tumor biopsies of breast tissue were collected from 100 patients with a confirmed diagnosis of invasive carcinoma, nonspecific type, between the ages of 31-80 years. Immunohistochemistry was used to determine the intracellular localization of phosphorylated and non-phosphorylated forms of HspB1. RESULTS: The result of this study showed that biopsies from patients with lymph node metastasis exhibited significantly higher levels of phosphorylated forms of HspB1 in the nucleus and cytoplasm compared with the group without lymph node metastasis. Analysis showed that the expression of phosphorylated forms of the chaperone HspB1 correlates with the amount and percentage of lymph node metastases affected. CONCLUSION: The nuclear expression of phosphorylated and non-phosphorylated forms of the chaperone HspB1 is a marker of tumor cells associated with lymphatic metastasis of breast cancer.