Prognostic value of proliferation markers expression in breast cancer

Knowledge mapping of AURKA in Oncology：An advanced Bibliometric analysis (1998-2023)

AURKA, also known as Aurora kinase A, is a key molecule involved in the occurrence and progression of cancer. It plays crucial roles in various cellular processes, including cell cycle regulation, mitosis, and chromosome segregation. Dysregulation of AURKA has been implicated in tumorigenesis, promoting cell proliferation, genomic instability, and resistance to apoptosis. In this study, we conducted an extensive bibliometric analysis of research focusing on Aurora-A in the context of cancer by utilizing the Web of Science literature database. Various sophisticated computational tools, such as VOSviewer, Citespace, Biblioshiny R, and Cytoscape, were employed for comprehensive literature analysis and big data mining from January 1998 to September 2023.The primary objectives of our study were multi-fold. Firstly, we aimed to explore the chronological development of AURKA research, uncovering the evolution of scientific understanding over time. Secondly, we investigated shifting trends in research topics, elucidating areas of increasing interest and emerging frontiers. Thirdly, we delved into intricate signaling pathways and protein interaction networks associated with AURKA, providing insights into its complex molecular mechanisms. To further enhance the value of our bibliometric analysis, we conducted a meta-analysis on the prognostic value of AURKA in terms of patient survival. The results were visually presented, offering a comprehensive overview and future perspectives on Aurora-A research in the field of oncology. This study not only contributes to the existing body of knowledge but also provides valuable guidance for researchers, clinicians, and pharmaceutical professionals. By harnessing the power of bibliometrics, our findings offer a deeper understanding of the role of AURKA in cancer and pave the way for innovative research directions and clinical applications.

Prognostic Significance of BIRC5/Survivin in Breast Cancer: Results from Three Independent Cohorts

Simple Summary

Survivin, coded by the BIRC5 gene, is the cell death preventing protein, which is important for cell division in normal and cancer cells. It is intensively studied as a cancer biomarker and target for antitumor therapy. In this study we asked if we could get clinically helpful information on how active BIRC5 is in breast cancer patients? We studied the BIRC5 protein level in tumor samples for breast cancer patients from a West Swedish cohort and its mRNA level in two different public gene expression databases. Survival analysis demonstrated that a higher BIRC5 protein or mRNA level was associated with poor survival in all cohorts and for different cancer subtypes. We show that BIRC5 is a promising independent cancer survival marker.

Abstract

Breast cancer (BC) histological and molecular classifications significantly improved the treatment strategy and prognosis. Inhibitor of apoptosis BIRC5/survivin is often overexpressed in cancers, however, indications of its importance in BC are inconsistent. We integrate BIRC5 protein and mRNA measures with clinical associates and long-term outcome in three independent cohorts Protein levels of BIRC5 were measured in primary lysates of 845 patients of the West Swedish BC cohort (VGR-BC) and linked to 5- and 27-years survival. The results were externally validated in transcriptomic data from METABRIC and SCAN-B cohorts. Survival analysis showed that high levels of BIRC5 were consistently associated with a poor probability of 5-year overall survival. High BIRC5 in VGR-BC contributed negatively to the disease-specific survival at 5 and 27 years. Subsets with different status by ER (estrogen receptor) expression and presence of nodal metastasis supported independent association of high BIRC5 with poor prognosis in all cohorts. In METABRIC and SCAN-B cohorts, high levels of BIRC5 mRNA were associated with the basal-like and luminal B molecular BC subtypes and with increasing histologic grade. BIRC5 is a sensitive survival marker that acts independent of ER and nodal status, and its levels need to be considered when making treatment decisions.

PROGNOSTIC VALUE OF TOPOISOMERASE 2-ALPHA AND B-MYB IN EARLY BREAST CANCER TREATED WITH ADJUVANT CHEMOTHERAPY

Breast cancer is the most common malignancy in females. Despite its well-established prognostic factors, our prognostic ability at an individual patient level remains limited. In this study, the immunohistochemical expression of B-Myb and DNA topoisomerase 2-alpha (Topo2a) was analyzed in primary tumors to identify patients with a higher risk of disease recurrence after adjuvant chemotherapy for early invasive breast cancer. We analyzed a cohort of 215 early invasive breast cancer patients having undergone surgery from 2002 to 2003 at the Zagreb University Hospital Centre, including 153 patients treated with adjuvant chemotherapy. All of them were followed-up prospectively for at least ten years according to routine institutional practice. Statistically significant correlations were found between B-Myb and Topo2a expression levels and particular well-established prognostic factors. B-Myb expression was lower in estrogen receptor (ER)-positive tumors (p=0.0773), whereas larger tumors and those with positive lymphovascular invasion displayed a statistically significantly higher B-Myb expression (p=0.0409 and p=0.0196). Higher tumor grade indicated higher Topo2a values (p=0.0102 and p=0.0069). The subgroup with the expression of both proteins above the median value had an almost statistically significantly (p=0.0613) inferior prognosis compared to the rest of the cohort. Study results showed the B-Myb and Topo2a expression to have a prognostic value in breast cancer patients after adjuvant chemotherapy, which should be additionally explored in future studies in a larger patient cohort.

AR/ER Ratio Correlates with Expression of Proliferation Markers and with Distinct Subset of Breast Tumors

The co-expression of androgen (AR) and estrogen (ER) receptors, in terms of higher AR/ER ratio, has been recently associated with poor outcome in ER-positive (ER+) breast cancer (BC) patients. The aim of this study was to analyze if the biological aggressiveness, underlined in ER+ BC tumors with higher AR/ER ratio, could be due to higher expression of genes related to cell proliferation. On a cohort of 47 ER+ BC patients, the AR/ER ratio was assessed by immunohistochemistry and by mRNA analysis. The expression level of five gene proliferation markers was defined through TaqMan^®-qPCR assays. Results were validated using 979 BC cases obtained from gene expression public databases. ER+ BC tumors with ratios of AR/ER ≥ 2 have higher expression levels of cellular proliferation genes than tumors with ratios of AR/ER < 2, in both the 47 ER+ BC patients (P < 0.001) and in the validation cohort (P = 0.005). Moreover, BC cases with ratios of AR/ER ≥ 2 of the validation cohort were mainly assigned to luminal B and HER2-enriched molecular subtypes, typically characterized by higher proliferation and poorer prognosis. These data suggest that joint routine evaluation of AR and ER expression may identify a unique subset of tumors, which show higher levels of cellular proliferation and therefore a more aggressive behavior.

Prognostic implications and oncogenic roles of MYBL2 protein expression in esophageal squamous-cell carcinoma

Background

The MYBL2 gene, a highly conserved member of the Myb transcription-factor family, has been implicated in the genesis and progression of many types of tumors.

Methods

We analyzed the expression of MYBL2 and Ki67 in tissue samples of esophageal squamous-cell carcinoma (ESCC) patients by immunohistochemistry. We further analyzed the effect of MYBL2 on cell proliferation and DNA replication using a CCK8 assay, 5-ethynyl-2′-deoxyuridine–retention assay, flow-cytometry analysis, real-time quantitative PCR, Western blot, and a xenograft model of ESCC cells in nude mice.

Results

MYBL2 expression was significantly higher in ESCC tissue when compared to the adjacent normal tissue (P=0.007). MYBL2 was found to be positively correlated with Ki67 (γ=0.286, P=0.003). Furthermore, Kaplan–Meier curves indicated that MYBL2 expression in ESCC tissue was associated with poor patient outcome (P<0.001), with MYBL2-positive patients who exhibited high Ki67 expression in ESCC tissue showing the worst prognosis for overall survival (P=0.003). Our in vitro results showed that downregulation of MYBL2 in ESCC cell lines inhibited cell proliferation and DNA replication (P<0.05 for both). We also found that loss of MYBL2 caused a reduction in levels of cell cycle-related G2/M proteins CDK1 and cyclin B1 in ESCC cells. In contrast, overexpression of MYBL2 caused an increase in these proteins. In vivo, we found that in nude mice that received cells knocked down for MYBL2, tumor growth was inhibited in comparison to the group that received control cells (P<0.05).

Conclusion

MYBL2 overexpression induces tumor proliferation in ESCC cells by regulating cell-cycle at the S and G2/M phase. Therefore, MYBL2 may serve as a novel prognostic biomarker in ESCC patients.

The cell cycle regulatory DREAM complex is disrupted by high expression of oncogenic B-Myb

Overexpression of the oncogene MYBL2 (B-Myb) is associated with increased cell proliferation and serves as marker of poor prognosis in cancer. However, the mechanism by which B-Myb alters the cell cycle is not fully understood. In proliferating cells, B-Myb interacts with the MuvB core complex including LIN9, LIN37, LIN52, RBBP4, and LIN54, forming the MMB (Myb-MuvB) complex, and promotes transcription of genes required for mitosis. Alternatively, the MuvB core interacts with Rb-like protein p130 and E2F4-DP1 to form the DREAM complex that mediates global repression of cell cycle genes in G0/G1, including a subset of MMB target genes. Here, we show that overexpression of B-Myb disrupts the DREAM complex in human cells, and this activity depends on the intact MuvB-binding domain in B-Myb. Furthermore, we found that B-Myb regulates the protein expression levels of the MuvB core subunit LIN52, a key adaptor for assembly of both the DREAM and MMB complexes, by a mechanism that requires S28 phosphorylation site in LIN52. Given that high expression of B-Myb correlates with global loss of repression of DREAM target genes in breast and ovarian cancer, our findings offer mechanistic insights for aggressiveness of cancers with MYBL2 amplification, and establish the rationale for targeting B-Myb to restore cell cycle control.

Novel Molecular Markers for Breast Cancer

The use of molecular biomarkers assures that breast cancer (BC) patients receive optimal treatment. Established biomarkers, such as estrogen receptor, progesterone receptor, HER2, and Ki67, have been playing significant roles in the subcategorization of BC to predict the prognosis and decide the specific therapy to each patient. Antihormonal therapy using 4-hydroxytamoxifen or aromatase inhibitors have been employed in patients whose tumor cells express hormone receptors, while monoclonal antibody to HER2 has been administered to HER2-positive BCs. Although new therapeutic agents have been developed in the past few decades, many patients still die of the disease due to relapse; thus, novel molecular markers that predict therapeutic failure and those that can be targets for specific therapy are expected. We have chosen four of such molecules by reviewing recent publications, which are cyclin E, B-Myb, Twist, and DMP1β. The oncogenicity of these molecules has been demonstrated in vivo and/or in vitro through studies using transgenic mice or siRNAs, and their expressions have been shown to be associated with shortened overall or disease-free survival of BC patients. The former three molecules have been shown to accelerate epithelial-mesenchymal transition that is often associated with cancer stem cell-ness and metastasis; all these four can be novel therapeutic targets as well. Thus, large prospective studies employing immunohistochemistry will be needed to establish the predictive values of these molecules in patients with BC.

Localization and upregulation of survivin in cancer health disparities: a clinical perspective

Survivin is one of the most important members of the inhibitors of apoptosis protein family, as it is expressed in most human cancers but is absent in normal, differentiated tissues. Lending to its importance, survivin has proven associations with apoptosis and cell cycle control, and has more recently been shown to modulate the tumor microenvironment and immune evasion as a result of its extracellular localization. Upregulation of survivin has been found in many cancers including breast, prostate, pancreatic, and hematological malignancies, and it may prove to be associated with the advanced presentation, poorer prognosis, and lower survival rates observed in ethnically diverse populations.

Aurora A is a prognostic marker for breast cancer arising in BRCA2 mutation carriers

Overexpression of the Aurora A kinase has been shown to have prognostic value in breast cancer. Previously, we showed a significant association between AURKA gene amplification and BRCA2 mutation in breast cancer. The aim of this study was to assess the prognostic impact of Aurora A overexpression on breast cancer arising in BRCA2 mutation carriers. Aurora A expression was evaluated by immunohistochemistry on breast tumour tissue microarrays from 107 BRCA2 999del5 mutation carriers and 284 of sporadic origin. Prognostic value of Aurora A nuclear staining was estimated in relation to clinical markers and adjuvant treatment, using multivariate Cox's proportional hazards ratio regression model. BRCA2 wild‐type allele loss was measured by TaqMan in BRCA2 mutated tumour samples. All statistical tests were two sided. Multivariate analysis of breast cancer‐specific survival, including proliferative markers and treatment, indicated independent prognostic value of Aurora A nuclear staining for BRCA2 mutation carriers (hazards ratio = 7.06; 95% confidence interval = 1.23–40.6; p = 0.028). Poor breast cancer‐specific survival of BRCA2 mutation carriers was found to be significantly associated with combined Aurora A nuclear expression and BRCA2 wild type allele loss in tumours (p < 0.001). Multivariate analysis indicated independent prognostic value of both positive Aurora A nuclear staining (hazards ratio = 10.09; 95% confidence interval = 1.19–85.4, p = 0.034) and BRCA2 wild type allele loss (hazards ratio = 9.63; 95% confidence interval = 1.81–51.0, p = 0.008) for BRCA2 mutation carriers. Aurora A nuclear expression was found to be a significant prognostic marker for BRCA2 mutation carriers, independent of clinical parameters and adjuvant treatment. Our conclusion is that treatment benefits for BRCA2 mutation carriers and sporadic breast cancer patients with Aurora A positive tumours may be enhanced by giving attention to Aurora A targeted treatment.

Variation in Sp1 binding sites correlates with expression of survivin in breast cancer

Survivin is the smallest member of the inhibitor of apoptosis (IAP) family and is deregulated in breast cancer, where it is associated with a poor overall prognosis. It is well established that survivin overexpression predominately occurs at the transcriptional level. Numerous transcription factors bind to specific sequences in the promoter regions of genes and are involved in transcriptional regulation. Specificity protein (Sp) 1 binding sites have been found in the promoter region of the survivin gene. The present study aimed to investigate whether variations in Sp1 binding sites affect survivin expression. Nested polymerase chain reaction followed by DNA sequencing were performed to analyze the survivin gene promoter region in 42 breast cancer tissue samples. Furthermore, survivin expression was assessed using immunohistochemistry. High survivin protein expression was found in 66.7% (28/42) of breast cancer tissue samples. In addition, 15 variations in seven Sp1 binding sites were detected in 12 samples and Sp1 binding site variation was found to be associated with low survivin expression in the 42 samples. These findings suggested that variations in Sp1 binding sites may be associated with survivin expression.