CNA Landscape of HER2-Negative Breast Cancer in Anthracycline-Based Neoadjuvant Chemotherapy Regimens

Critical evaluation of how and when to include anthracyclines in preoperative chemotherapy is becoming more relevant in an era when the molecular genetic approach not only allows for the development of biologically targeted therapeutics, but also implies the ability to select the patients likely to benefit from certain cytotoxic agents. Changes in the copy number aberration (CNA) landscape of luminal B HER2- negative (HER2-) breast cancer (BC) during anthracycline-based neoadjuvant chemotherapy (NAC) regimens were studied in order to identify groups of potential CNA markers of objective response and CNA markers for predicting the development of hematogenous metastasis. Comparison of CNA frequencies depending on the response to NAC showed that objective response was observed in a larger number of deletions in the 11q22.3 and 11q23.1 loci (p = 0.004). Comparison of CNA frequencies in groups of patients after treatment showed that hematogenous metastasis was observed with a greater number of amplifications in the 9p22.2 locus (p = 0.003) and with a greater number of deletions in the 9p21.3 locus (p = 0.03). Potential predictive CNA markers of objective response and prognostic CNA markers of hematogenous metastasis in anthracycline- based NAC regimens have been identified.

MALAT1 Long Non-coding RNA and Its Role in Breast Carcinogenesis

Our genome consists not only of protein-coding DNA, but also of the non-coding part that plays a very important role in the regulation of all cellular processes. A part of the non-coding genome comes with non-coding RNAs (ncRNAs), and disruption of the functional activity of these RNAs may be associated with oncogenesis in various cancer types. There exist two types of ncRNAs: small and long non-coding RNAs, which are classified according to their transcript length. Long non-coding metastasis-associated lung adenocarcinoma transcript 1, MALAT1 RNA (NEAT2), is a long non-coding RNA of particular interest. The aforementioned transcript takes part in the regulation of numerous cellular processes and pathogenesis of different malignant tumors, including breast tumors. This review focuses on experimental and clinical studies into the role of MALAT1 in carcinogenesis and the progression of breast cancer.

Expression heterogeneity of ABC-transporter family genes and chemosensitivity genes in gastric tumor, carcinomatosis and lymph node metastases

Introduction. Metastatic tumors (particularly gastric cancer) have been found to be characterized by heterogeneity between the primary tumor and metastases. This type of heterogeneity comes to the fore when treating primary-metastatic forms of tumor and is an important reason for the low effectiveness of their treatment. In this regard, comparative analysis of ABC-transporter gene expression and chemosensitivity genes will allow to characterize to a certain extent the resistance and sensitivity of primary tumor, carcinomatosis and metastases to therapy and provide the basis for personalized treatment approach.Aim. To evaluate expression heterogeneity of ABC-transporter genes and chemosensitivity genes in gastric tumor, carcinomatosis and lymph node metastases.Materials and methods. Overall 41 patients with disseminated gastric cancer stage IV with carcinomatosis of peritoneum were included in the investigation. All patients underwent surgery according to Roux palliative gastrectomy. After surgery patients underwent chemotherapy depending on indications. RNA was isolated using RNeasy Plus mini kit (Qiagen, Germany). The expression level of ABC transporter genes (ABCB1, ABCC1, ABCC2, ABCC5, ABCG1, ABCG2) and chemosensitivity genes (BRCA1, RRM1, ERCC1, TOP1, TOP2α, TUBβ3, TYMS, GSTP1) was assessed by reverse transcription polymerase chain reaction (RT-PCR) in primary tumor, carcinomatosis and lymph node metastases.Results. The expression levels of the genes under study were shown to vary widely. For ABC transporter genes, ABCG1 (3.1 ± 1.1; max 32.0), ABCG2 (7.9 ± 2.3; max 54.1), ABCG2 (9.6 ± 3.8; max 101.0) were the most expressed genes in gastric tumor tissue, carcinomatosis and lymph node metastasis, respectively. Hyperexpression among chemosensitivity genes at all three sites was characteristic only of TOP2α (17.2 ± 6.0; max. 161.9; 10.8 ± 4.1; max. 105.1; 35.3 ± 0.8; max. 439.6, respectively). We found that TOP2α and BRCA1 gene expression levels were higher in lymph node metastasis compared with gastric tumor tissue and carcinomatosis (at p = 0.005 and p = 0.001). Whereas ABCC1 gene expression was statistically significantly higher in carcinomatosis (p = 0.03).Conclusion. Thus, a high level of expression heterogeneity is observed in gastric cancer, which affects the expression patterns of various genes in different localizations. The expression profile can be used to determine the level of heterogeneity and approach to personalized therapy tactics.

In vitro modeling of tumor interclonal interactions using breast cancer cell lines

AIM

To study the peculiarities of ecological relationships of breast cancer (BC) cell lines MCF-7, BT-474 and MDA-MD-231 under co-culturing conditions.

MATERIALS AND METHODS

Three BC cell lines: luminal A - MCF-7, luminal B - BT-474 and triple-negative - MDA-MD-231 were co-cultured pairwise. Immunocytochemistry was used to differentiate the cell lines in the wells. The effect of the cell-free culture medium on the growth rate of the alternate cell line in the pair was also evaluated.

RESULTS

It was shown that when BT-474 cells were co-cultured with MCF-7 and BT-474 cells were co-cultured with MDA-MD-231, two types of ecological interactions could be observed: commensalism and amensalism, respectively. While the cells do not interact with each other in contact, the supernatants of single cultures of MCF-7 and MDA-MD-231 exert the same effect on BT-474 as co-cultivation of BT-474 with these cells.

CONCLUSIONS

The paracrine mechanism of intercellular interaction between different human BC cell lines has been demonstrated. The models used in population ecology can be applicable to identify the types of interaction between cell lines.

NF-kB as a potential prognostic marker and a candidate for targeted therapy of cancer

The NF-kB1 gene belongs to the family of transcription factors that are involved in the regulation of a wide range of biological reactions. It has been established that NF-kB1 plays an important role in the regulation of immune responses, but more and more studies indicate that this gene is involved in the processes of oncogenesis and DNA repair. The product of this gene regulates the expression of genes involved in the development and progression of cancer. In recent years, numerous studies have been aimed at elucidating the functional consequences of the activation of NF-kB1, as well as its signaling mechanisms. In this regard, NF-kB1 is an interesting therapeutic target for a possible personalized approach in the treatment of cancer. This article provides an overview of modern clinical studies of the NF-kB1 gene, which acts as a predictive and prognostic marker in the treatment of cancer.

[Viral co-infection with head and neck tumors]

The review is devoted to assessing the prevalence of human papillomavirus (HPV) in combination with other viral agents for head and neck tumors (HNT). HPV is recognized as an etiological factor in the development of cervical cancer, but there is evidence that it may be involved in carcinogenesis in other locations, in particular the upper respiratory tract. However, HPV is not the most important factor in tumor growth and progression. Recently, many researchers have reported the presence of concomitant co-infection, affecting tumor progression. Of all the studies analyzed, only 3 studies showed the absence or low rates of co-infection in HNT: from the Czech Republic (0%), China (0.6%) and Japan (3%). Most often, HPV infection was detected together with the Epstein-Barr virus (EBV) - from 12.5 to 34.1% of cases. In Russia, the prevailing combination of viral co-infection was a combination of EBV and cytomegalovirus (9.5%) and a combination of EBV and herpes simplex virus (6.7%). Thus, the degree of incidence of HPV in HNT varies greatly, and the mechanisms of coinfection are poorly understood, which raises the question of whether HPV and concomitant infection can be involved in tumor progression. This makes further research in this direction relevant and promising.

Genome-wide association study of loss of heterozygosity and metastasis-free survival in breast cancer patients

One of the factors providing the diversity and heterogeneity of malignant tumors, particularly breast cancer, are genetic variations, due to gene polymorphism, and, especially, the phenomenon of loss of heterozygosity (LOH). It has been shown that LOH in some genes could be a good prognostic marker.

AIM

To perform genome-wide study on LOH in association with metastasis-free survival in breast cancer.

MATERIALS AND METHODS

The study involved 68 patients with breast cancer. LOH status was detected by microarray analysis, using a high density DNA-chip CytoScanTM HD Array (Affymetrix, USA). The Chromosome Analysis Suite 3.1 (Affymetrix, USA) software was used for result processing.

RESULTS

13,815 genes were examined, in order to detect LOH. The frequency of LOH varied from 0% to 63%. The association analysis identified four genes: EDA2R, PGK1, TAF9B and CYSLTR1 that demonstrated the presence of LOH associated with metastasis-free survival (log-rank test, p < 0.03).

CONCLUSIONS

The presence of LOH in EDA2R, TAF9B, and CYSLTR1 genes is associated with metastasis-free survival in breast cancer patients, indicating their potential value as prognostic markers.

Natural and Chemotherapy-Induced Clonal Evolution of Tumors

Evolution and natural selection of tumoral clones in the process of transformation and the following carcinogenesis can be called natural clonal evolution. Its main driving factors are internal: genetic instability initiated by driver mutations and microenvironment, which enables selective pressure while forming the environment for cell transformation and their survival. We present our overview of contemporary research dealing with mechanisms of carcinogenesis in different localizations from precancerous pathologies to metastasis and relapse. It shows that natural clonal evolution establishes intratumoral heterogeneity and enables tumor progression. Tumors of monoclonal origin are of low-level intratumoral heterogeneity in the initial stages, and this increases with the size of the tumor. Tumors of polyclonal origin are of extremely high-level intratumoral heterogeneity in the initial stages and become more homogeneous when larger due to clonal expansion. In cases of chemotherapy-induced clonal evolution of a tumor, chemotherapy becomes the leading factor in treatment. The latest research shows that the impact of chemotherapy can radically increase the speed of clonal evolution and lead to new malignant and resistant clones that cause tumor metastasis. Another option of chemotherapy-induced clonal evolution is formation of a new dominant clone from a clone that was minor in the initial tumor and obtained free space due to elimination of sensitive clones by chemotherapy. As a result, in ~20% of cases, chemotherapy can stimulate metastasis and relapse of tumors due to clonal evolution. The conclusion of the overview formulates approaches to tumor treatment based on clonal evolution: in particular, precision therapy, prediction of metastasis stimulation in patients treated with chemotherapy, methods of genetic evaluation of chemotherapy efficiency and clonal-oriented treatment, and approaches to manipulating the clonal evolution of tumors are presented.

Integrative and episomal forms of genotype 16 of human papillomavirus in patients with cervical intraepithelial neoplasia and cervical cancer

The study involved 500 patients with LSIL (low grade squamous intraepithelial lesion), HSIL (high grade squamous intraepithelial lesion), stage I-IV cervical cancer, infected with human papillomavirus (HPV), as well as 235 women without pathological changes in cervical mucosa. The comprehensive survey included colposcopy, cytological and histological analysis, detection and genotyping of high-risk human papillomavirus. Viral load and physical status of HPV16 DNA was evaluated in cases of mono-infection (n = 148). The prevalence of virus-positive cases among the patients with LSIL/NSIL, cervical cancer patients and healthy women was 69.2%, 76.7% and 51.9%, respectively. An association between the severity of disease and high viral load was revealed. The frequency of integrated DNA was strongly increased in patients with a high viral load. The frequency of episomal forms was either reduced or not detecteable in patients with high viral load as compared to patients with low viral load. It is reasonable to suggest that a high HPV16 viral load may cause an increase in the frequency of integration of virus DNA into the cellular/host genome. This suggests that a high HPV16 viral load may be considered as a risk factor for prognosis of cervical intraepithelial neoplasia and cervical cancer.

Comprehensive meta-analytical summary on human papillomavirus association with head and neck cancer

An etiological role of high risk human papillomavirus (HPV) in the development of cervical cancer has been well established. Hence, attention of researchers has been focused on the role of HPV in pathogenesis of other malignancies, such as head and neck cancers. An analysis of epidemiological data on the prevalence of HPV infection among healthy people and patients with precancerous lesions and/or cancer is an important step in understanding the role of HPV in head and neck carcinogenesis. More and more data de-monstrate the impact of HPV infection on disease outcome. HPV-positive patients have been shown to have better responses to radiotherapy and better overall and disease-free survival than HPV-negative patients. This review presents data of the meta-analysis based on a large number of original studies on HPV prevalence in patients with precancerous lesions and in patients with oral, oropharyngeal and laryngeal cancers as well as findings on the impact of HPV infection on survival of these patients.