One of the important reasons for the ineffectiveness of chemotherapy in breast cancer (BC) is considered to be the formation of a multidrug resistance phenotype in tumour cells, which is caused by the expression of energy-dependent ABC transporters. The aim of this work was to assess chromosomal aberrations and the level of transcripts of all 49 known ABC transporter genes in breast tumours. Materials and Methods. The study included 129 patients with breast cancer. A microarray study of all tumour samples was carried out on microchips. Results. This study established that the presence of a deletion in genes ABCB1, ABCB4, ABCB8, ABCC7, ABCC11, ABCC12, ABCF2, and ABCG4 is associated with an objective response to treatment (p ≤ 0.05). A decrease in the expression of genes was associated with a good response to chemotherapy, whereas an increase in expression caused the progression and stabilization of the tumour. Analysis of metastatic-free survival rates showed that the presence of ABCB1/4 and ABCC1/6 deletions was associated with 100% survival (log-rank test p = 0.01 and p = 0.03). Conclusions. The study showed that the aberrant state of ABC transporter genes, as well as a decrease in the expression of these genes, is a predictor of the effectiveness of therapeutic treatment and a potential prognostic marker of metastatic survival.

Increasingly, many researchers are focusing on the sensitivity in breast tumors (BC) to certain chemotherapy drugs and have personalized their research based on the assessment of this sensitivity. One such personalized approach is to assess the chemotherapy’s gene expression, as well as aberrations in the number of DNA copies—deletions and amplifications with the ability to have a significant effect on the gene’s activity. Thus, the aim of this work was to study the predictive and prognostic significance of the expression and chromosomal aberrations of eight chemosensitivity genes in breast cancer patients. Material and methods. The study involved 97 patients with luminal B breast cancer IIB–IIIB stages. DNA and RNA were isolated from samples of tumor tissue before and after treatment. Microarray analysis was performed for all samples on high-density microarrays (DNA chips) of Affymetrix (USA) CytoScanTM HD Array and Clariom™ S Assay, human. Detection of expression level of seven chemosensitivity genes—RRM1, ERCC1, TOP1, TOP2a, TUBB3, TYMS, and GSTP1—was performed using PCR real-time (RT-qPCR). Results. The expression of the RRM1 (AC scheme), TOP2α, TYMS, and TUBB3 genes in patients with an objective response to treatment (complete and partial regression) is higher than in patients with stabilization and progression (p < 0.05). According to our results, the presence of a high level of GSTP1 in a tumor biopsy is associated with the low efficiency of the NAC CP scheme (p = 0.05). The presence of RRM1 deletion is associated with complete and partial regression, as for the TOP1 and TUBB3 genes (p < 0.05). Higher rates of metastatic survival are associated with a high level of expression and amplification of the GSTP1 gene (log-rank test p = 0.02 and p = 0.05). Conclusion. Thus, a complex assessment of the chemotherapy’s gene expression is important not only for understanding the heterogeneity and molecular biology of breast cancer but also to obtain a more accurate disease prognosis.

Background: The aim of this study was to evaluate data over the past 25 years to assess the prevalence of the virus in patients with bladder cancer and to evaluate the association between human papillomavirus (HPV) and bladder cancer risk. Main text: Major databases were searched for published studies from October 1995 to May 2022. The present study evaluated the prevalence of HPV in patients with bladder cancer and the prevalence according to patients' ethnicity. The incidence of HPV in bladder cancer patients varies widely, ranging from complete absence of the virus in tissues to 64.6%. The meta-analysis was performed using Meta-Essentials_1.5 software. Begg’s and Egger’s methods were used to assess publication bias. Cochran’s Q test was used to assess heterogeneity and the I2 index was employed for calculating the variation in the pooled estimations. Conclusions: A weak association of HPV infection with the risk of bladder cancer was found. The risk of bladder cancer with HPV infection has clear ethnic characteristics and is statistically significant in Arabs and Asians.

Background: the present study aims to prove or disprove the hypothesis that the state of copy number aberration (CNA) activation of WNT signalling pathway genes accounts for the ability of differentiated tumour cells to emerge from postchemotherapy shock. Methods: In the first step, the CNA genetic landscape of breast cancer cell lines BT-474, BT-549, MDA-MB-231, MDA-MD-468, MCF7, SK-BR-3 and T47D, which were obtained from ATCC, was examined to rank cell cultures according to the degree of ectopic activation of the WNT signalling pathway. Then two lines of T47D with ectopic activation and BT-474 without activation were selected. The differentiated EpCAM+CD44-CD24-/+ cells of these lines were subjected to IL6 de-differentiation with formation of mammospheres on the background of cisplatin and WNT signalling inhibitor ICG-001. Results: it was found that T47D cells with ectopic WNT signalling activation after cisplatin exposure were dedifferentiated to form mammospheres while BT-474 cells without ectopic WNT-signalling activation did not form mammospheres. The dedifferentiation of T47D cells after cisplatin exposure was completely suppressed by the WNT signalling inhibitor ICG-001. Separately, ICG-001 reduced, but did not abolish, the ability to dedifferentiate in both cell lines. Conclusions: these data support the hypothesis that the emergence of differentiated tumour cells from postchemotherapy shock after chemotherapy is due to ectopic activation of WNT signalling pathway genes.

The aim of the study was mammosphere assay optimization for quantifcation of IL6-induced stemness in differentiated (СD44^– ) T47D breast cancer cells.Material and Methods. The effect of three commonly used cell-detaching methods (TrypLE, accutase, cell scrapper) at various confuence (40–50 % and 70–80 %) on cell viability, phenotypic profle and mammosphere formation was tested. The cell viability was examined using AnnexinV/propidium iodide assay. The phenotypic profle was analyzed by fow cytometry with fuorescent markers CD24 and CD44.Results. Detachment of the cells using scrapper led to substantial increase in early apoptotic and late apoptotic cells in comparison with TrypLE and accutase. Dissociation with TrypLE reduced the percentage of detected CD44⁺ positive cells, whereas accutase saved the surface marker. The number of mammosphere and their diameter did not differ between groups. Incubation of differentiated (CD44^– CD24⁺) T47D cells with IL-6 for 24 hours resulted in an appearance of CD44⁺CD24⁺ and CD44⁺CD24^–/low subpopulation. Furthermore, the differentiated cells after 24 hours of IL6 exposure formed 3 times more mammospheres compared to the control.Conclusion. Usage of cells with confuence of no more than 80 % and accutase for detachment of cells is recommended for mammosphere assay. Incubation of CD44^– CD24⁺ T47D cells with IL6 for 24 hours is suffcient for stimulation of stemness plasticity.

It is known that currently PARP inhibitors are actively used in the treatment of tumors of the female reproductive system. A large number of studies have been presented demonstrating the effectiveness of PARP inhibitors in the treatment of BRCA-associated ovarian cancer. It was found that mutations in the BRCA1 and BRCA2 genes are also characteristic of breast cancer (BC). However, PARP inhibitors are rarely used in clinical practice in the treatment of BC. So far, only olaparib has become the first PARP inhibitor approved for the treatment of metastatic BC. This review presents data over the past ten years showing the high efficiency of PARP inhibitors in the treatment of malignant neoplasms of the mammary gland. In 7 of 28 studies analyzed, positive results were achieved with combined treatment with chemotherapeutic drugs and PARP inhibitors. So, for example, in two studies in the treatment of BRCA-associated BC, the response to treatment in patients was 72.5–73.2 %. Thus, PARP inhibitors are of great interest and are of practical value in the treatment of patients with BC.