Soluble forms of PD-1/PD-L immune checkpoint receptor and ligand in blood serum of breast cancer patients: association with clinical pathologic factors and molecular type of the tumor.

Results of enzyme-linked immunosorbent assay of the soluble forms of PD-1/PD-L immune checkpoint receptor and ligand (sPD-1 and sPD-L1) in pretreatment blood serum of 88 breast cancer patients at various disease stages aged 30-83 years are presented. The control group included 55 practically healthy women aged 19-82 years. Serum sPD-1 and sPD-L1 levels in breast cancer patients highly significantly (p<0.0001) differ from control and these changes are opposite: soluble receptor level is more than 6-fold decreased, while soluble ligand concentration - 5.5 fold increased. Both markers separately, as well as their ratio demonstrate very high sensitivity (94-100%) and specificity (95-100%) in relation to healthy control. No statistically significant associations of sPD-1 and sPD-L1 levels with clinical stage, individual TNM system criteria, tumor histological structure, grade, receptor status, and molecular type were established. In particular, no significant peculiarities of the markers' levels in triple negative breast cancer successfully treated with anti-PD-1/PD-L1 preparations were revealed. Long-term follow-up and dynamic studies of sPD-1 and sPD-L1serum levels in the course of treatment are required for evaluation of their independent from clinical and morphological factors prognostic significance and the possibility of application as low invasive tests for prediction and monitoring of corresponding targeted therapy efficiency.

Prognostic Molecular and Biological Characteristics of Phyllodes Tumors of the Breast.

Prognosis for some histological variants of a rare breast disease, phyllodes tumors, is evaluated. The prognostic potential of some molecular biological factors significantly correlating with breast cancer prognosis is evaluated on a unique clinical material (244 cases with benign, intermediate, and malignant phyllodes tumors). The development of benign phyllodes tumor relapse directly correlated with the number of G0/1-phase cells and inversely correlated with the number of cells in the G2+M and S phases. The level of steroid hormone receptors in phyllodes tumors cannot serve as a prognostic marker predicting the disease course. The presence of somatic mutations of TP53 gene and loss of heterozygosity of specific intragenic loci in the tumor correlate with the development of disease relapse (p<0.05).

Molecular Pathway Activation Markers Are Associated with Efficacy of Trastuzumab Therapy in Metastatic HER2-Positive Breast Cancer Better than Individual Gene Expression Levels.

Increased expression or amplification of HER2 receptor tyrosine kinase gene ERBB2 is well-known and widely used as a prognostic biomarker of breast cancer (BC) response to the targeted treatment with trastuzumab and its analogs. Considering that part of the BC patients overexpressing HER2 does not respond to trastuzumab, clinical trial NCT03521245 was initiated to identify additional gene expression and molecular pathway activation response biomarkers to trastuzumab treatment in HER2-positive BC. Using RNA sequencing gene expression in 23 formalin-fixed, paraffin embedded HER2 positive BC tissue blocks from patients who either responded or not responded to trastuzumab treatment was profiled. Differentially regulated genes and molecular pathways were identified in the groups of trastuzumab responders and non-responders. These results were next compared with the 42 previously published BC trastuzumab responder and non-responder RNA sequencing profiles from the clinical trials NCT00513292 and NCT00353483. No correlation was observed between the response status and the expression levels of ERBB2 gene in the HER2 positive BC samples. Analysis of the differentially expressed genes and molecular pathways in the combined dataset revealed 15/27 commonly up/down regulated genes and 15/25 pathways, respectively. However, only the intersection of molecular pathways upregulated in trastuzumab responders vs non-responders was statistically significantly enriched compared to the random expectation model. A classifier built using the most significantly upregulated molecular pathway - cAMP Pathway Protein Retention - demonstrated the best performance for prediction of the HER2 positive BC response to trastuzumab for both our experimental and previously reported data. This pathway also predicted time to recurrence in the combined dataset with Log-rank p-value 0.041.

Polyoxidonium® Activates Cytotoxic Lymphocyte Responses Through Dendritic Cell Maturation: Clinical Effects in Breast Cancer.

Immunotherapy, which is seen as a major tool for cancer treatment, requires, in some cases, the presence of several agents to maximize its effects. Adjuvants can enhance the effect of other agents. However, despite their long-time use, only a few adjuvants are licensed today, and their use in cancer treatment is rare. Azoximer bromide, marketed under the trade name Polyoxidonium® (PO), is a copolymer of N-oxidized 1,4-ethylenepiperazine and (N-carboxyethyl)-1,4-ethylene piperazinium bromide. It has been described as an immune adjuvant and immunomodulator that is clinically used with excellent tolerance. PO is used in the treatment and prophylaxis of diseases connected with damage to the immune system, and there is interest in testing it in antitumor therapy. We show here that PO treatment for 1 week induced positive pathological changes in 6 out of 20 patients with breast cancer, including complete response in a triple-negative patient. This correlated with an increased tumor CD4+ T-lymphocyte infiltration. The immune effects of PO are associated with myeloid cell activation, and little is known about the action of PO on lymphocyte lineages, such as natural killer (NK) and T cells. We reveal that PO increases T-cell proliferation in vitro without negative effects on any activation marker. PO does not affect dendritic cell (DC) viability and increases the expansion of immature DC (iDC) and mature DC (mDC) at 100 µg/ml, and it stimulates expression of several DC co-stimulatory molecules, inducing the proliferation of allogeneic T cells. In contrast, PO decreases DC viability when added at day 5 post-expansion. PO is not toxic for NK cells at doses up to 100 µM and does not affect their activation, maturation, and cytotoxicity but tends to increase degranulation. This could be beneficial against target cells that show low sensitivity to NK cells, e.g., solid tumor cells. Finally, we have found great variability in PO response between donors. In summary, our in vitro results show that PO increases the number of costimulatory molecules on DC that prime T cells, favoring the production of effector T cells. This may support the future clinical development of PO in cancer treatment.

Analysis of informativeness of immunohistochemical and flow cytometric methods for estrogen receptor α assessment.

Informative capacity analysis of immunohistochemistry (IHC) and flow cytometry (FCM) in the assessment of estrogen receptor α (ERα) expression in breast cancer tissue was performed. Similar frequencies of expression were shown by both methods: 27% of ERα-negative and 73% ERα-positive cases. However, IHC evaluation detected low levels in only 20% of ERα-positive cases, whereas low levels of ERα detected by FCM were 2 times more often (48%). Moreover, FCM revealed positive expression (23-60%) in 33% of IHC ERα-negative cases. Among IHC ER-positive cases, zero ERα expression was detected by FCM in 12.5%. The approaches to minimize errors in routine clinical determination of the estrogen receptor status were proposed.

Vascular endothelial growth factor in the serum of breast cancer patients.

Here we present the results of comparative immunoenzyme assay of the initial serum levels of VEGF in breast cancer patients (stages T1N0M0 and T2N0M0) and apparently healthy women (controls). It was found that VEGF concentrations in the serum of patients with breast cancer stages T1N0M0 and T2N0M0 significantly surpassed the control levels. Increased levels of VEGF surpassing the threshold values were more often observed in patients with T2N0M0 breast cancer compared to patients with T1N0M0 tumor. At the same time, this marker cannot be used in the diagnostics of this disease because in only 21.4% patients serum level of VEGF surpassed the upper boundary for this growth factor observed in the serum of control women. Serum concentration of VEGF in patients with stages T1N0M0 and T2N0M0 breast cancer did not depend on patient's age and reproductive function and receptor status of the primary tumor (estrogen and progesterone receptors), but was closely associated with tumor histogenesis and differentiation degree. Significantly higher levels of VEGF were observed in patients with lobular infiltrative breast carcinoma compared to patients with ductal tumors and in patients with low-differentiated tumors compared to highly and moderately differentiated tumors. High initial concentrations of VEGF (>300 pg/ml) were more often detected in patients with T2N0M0 breast cancer developing relapses within the first 3 years of follow-up compared to patients without relapses during the corresponding period (p=0.001). These findings suggest that serum level of VEGF in patients with T2N0M0 breast cancer before treatment can be used as an additional marker in parallel with standard clinical and morphological signs of the disease for more precise prognosis of early relapse (during the first 3 years of follow-up).