Breast cancer biology and ethnic disparities in breast cancer mortality in new zealand: a cohort study

The Tumorigenic Role of Circular RNA-MicroRNA Axis in Cancer

Circular RNAs (circRNAs) are a class of endogenous RNAs that control gene expression at the transcriptional and post-transcriptional levels. Recent studies have increasingly demonstrated that circRNAs act as novel diagnostic biomarkers and promising therapeutic targets for numerous cancer types by interacting with other non-coding RNAs such as microRNAs (miRNAs). The miRNAs are presented as crucial risk factors and regulatory elements in cancer by regulating the expression of their target genes. Some miRNAs are derived from transposable elements (MDTEs) that can transfer their location to another region of the genome. Genetic interactions between miRNAs and circular RNAs can form complex regulatory networks with various carcinogenic processes that play critical roles in tumorigenesis and cancer progression. This review focuses on the biological regulation of the correlative axis among circular RNAs, miRNAs, and their target genes in various cancer types and suggests the biological importance of MDTEs interacting with oncogenic or tumor-suppressive circRNAs in tumor progression.

Grading of invasive breast carcinoma: the way forward

Histologic grading has been a simple and inexpensive method to assess tumor behavior and prognosis of invasive breast cancer grading, thereby identifying patients at risk for adverse outcomes, who may be eligible for (neo)adjuvant therapies. Histologic grading needs to be performed accurately, on properly fixed specimens, and by adequately trained dedicated pathologists that take the time to diligently follow the protocol methodology. In this paper, we review the history of histologic grading, describe the basics of grading, review prognostic value and reproducibility issues, compare performance of grading to gene expression profiles, and discuss how to move forward to improve reproducibility of grading by training, feedback and artificial intelligence algorithms, and special stains to better recognize mitoses. We conclude that histologic grading, when adequately carried out, remains to be of important prognostic value in breast cancer patients.

The role and underlying mechanism of miR-1299 in cancer

A type of evolutionarily conserved, noncoding, small, endogenous, single-stranded RNA, miRNAs are widely distributed in eukaryotes, where they participate in various biological processes as critical regulatory molecules. miR-1299 has mainly been investigated in cancers. miR-1299 is a tumor suppressor that regulates the expression of its target genes, activating or inhibiting the transcription of genes regulating biological activities including cell proliferation, migration, survival and programmed cell death. miR-1299 has become a hotspot in research of disease mechanisms and biomarkers; elucidation of the regulatory roles of miR-1299 in tumorigenesis, proliferation, apoptosis, invasion, migration and angiogenesis may provide a new perspective for understanding its biological functions as a tumor suppressor.

As key regulatory molecules, microRNAs participate in various biological processes and have become a widespread research focus. This article discusses how the microRNA miR-1299 plays a role as a tumor suppressor and participates in the regulation of tumor pathogenesis. We provide an overview of the role of miR-1299 in tumor diseases and discuss the pathogenesis and regulation mechanisms of miR-1299 in different specific cancers.

Variation in breast cancer grading: the effect of creating awareness through laboratory-specific and pathologist-specific feedback reports in 16 734 patients with breast cancer

AIMS

Histological grade is widely used to guide the management of invasive breast cancer (IBC). Yet, substantial interlaboratory and intralaboratory grading variations exist in daily pathology practice. To create awareness and to facilitate quality improvement, feedback reports, containing case-mix-adjusted laboratory-specific grades benchmarked against other laboratories, were sent to the individual laboratories by 1 March 2018. We studied the effect of these feedback reports on interlaboratory grading variation up till 1 year later.

METHODS

Overall, 17 102 synoptic pathology reports of IBC resection specimens from 33 laboratories, obtained between 1 March 2017 and 1 March 2019 were retrieved from the Dutch Pathology Registry (PALGA). An overall deviation score (ODS), representing the sum of deviations from the grade-specific overall proportions, was calculated to compare the absolute deviation for all grades at once. Case-mix correction was performed by two multivariable logistic regression analyses, providing laboratory-specific ORs for high-grade versus low-grade IBC.

RESULTS

After feedback, the overall range between laboratories decreased by 3.8%, 6.4% and 6.6% for grades I, II and III, respectively. Though the mean ODS remained similar (13.8% vs 13.7%), the maximum ODS decreased from 34.1% to 29.4%. The range of laboratory-specific ORs decreased by 21.9% for grade III versus grades I-II.

CONCLUSIONS

An encouraging decrease in grading variation of IBC was observed after laboratory-specific feedback. Nevertheless, the overall grading variation remains substantial. In view of the important role of grading in patient management, it is adamant that not only feedback should be provided on a regular basis but also other interventions, such as additional training, are required.

Significant inter- and intra-laboratory variation in grading of invasive breast cancer: A nationwide study of 33,043 patients in the Netherlands

Accurate, consistent and reproducible grading by pathologists is of key-importance for identification of individual patients with invasive breast cancer (IBC) that will or will not benefit from adjuvant systemic treatment. We studied the laboratory-specific grading variation using nationwide real-life data to create insight and awareness in grading variation. Synoptic pathology reports of all IBC resection-specimens, obtained between 2013 and 2016, were retrieved from the nationwide Dutch Pathology Registry (PALGA). Absolute differences in laboratory-proportions of Grades I-III were compared to the national reference. Multivariable logistic regression provided laboratory-specific odds ratios (ORs) for high- vs. low-grade IBC. 33,792 IBC pathology reports of 33,043 patients from 39 laboratories were included, of which 28.1% were reported as Grade I (range between laboratories 16.3-43.3%), 47.6% as Grade II (38.4-57.8%), and 24.3% as Grade III (15.5-34.3%). Based on national guidelines, the indication for adjuvant chemotherapy was dependent on histologic grade in 29.9% of patients. After case-mix correction, 20 laboratories (51.3%) showed a significantly deviant OR. Significant grading differences were also observed among pathologists within laboratories. In this cohort of 33,043 breast cancer patients, we observed substantial inter- and intra-laboratory variation in histologic grading. It can be anticipated that this has influenced outcome including exposure to unnecessary toxicity, since choice of adjuvant chemotherapy was dependent on grade in nearly a third of patients. Better standardization and training seems warranted.

Circular RNAs: A novel target among non‑coding RNAs with potential roles in malignant tumors (Review)

Circular RNAs (circRNAs) are a class of non-coding RNAs that are generated via alternative back-splicing, which connects the terminal 5′ and 3′ends. Due to their unique loop structure, circRNAs are resistant to ribonucleases and more stable than linear RNAs. In vivo, they are usually highly conserved and stably expressed in tissue/developmental-stage-specific manners. Generally, circRNAs function as microRNA sponges and splicing regulators, as well as in protein binding and transcription. Some circRNAs contain open reading frames with internal ribosomal entry site elements and can thus encode specific proteins. Previously, circRNAs were thought to be erroneous splicing products or by-products of mRNA splicing. With the development of the next-generation sequencing techniques, it has become increasingly clear that circRNAs are abundantly widespread in eukaryotes and that they play significant roles in malignant tumor progression. The present review briefly introduces the biogenesis and functions of circRNAs, as well as summarizes recent research in several common malignancies. The present review also addresses the prospects of circRNAs in clinical applications.

Upregulation of hsa_circ_0136666 contributes to breast cancer progression by sponging miR-1299 and targeting CDK6

Circular RNAs (circRNAs) can participate in multiple cancers, including breast cancer. Increasing circRNAs are recognized in various cancers because of the high-throughput sequencing. However, the potential physiological effect of hsa_circ_0136666 in breast cancer progression is unknown. In our study, the biological role of hsa_circ_0136666 in breast cancer development was studied. It was displayed that hsa_circ_0136666 was greatly increased in breast cancer. In addition, overexpression of hsa_circ_0136666 was able to promote Michigan Cancer Foundation-7 (MCF7) and BT474 cell proliferation and triggered cell cycle in G2/M phase. microRNA plays critical role in tumor development and they can act as direct targets of circRNAs. miR-1299 has been implicated as a famous tumor suppressor in many cancers. Here, miR-1299 was predicted as the target of hsa_circ_0136666. Meanwhile, its Upregulation repressed breast cancer proliferation, migration and invasion capacity, which could be reversed by the increase of hsa_circ_0136666. Furthermore, Cyclin-dependent kinase 6 (CDK6) was speculated as the downstream target of miR-1299. In MCF7 and BT474 cells, CDK6 was greatly overexpressed and it was shown that CDK6 contributed a lot to breast cancer progression. Subsequently, it was implied that hsa_circ_0136666 could modulate CDK6 levels positively in vitro. In conclusion, it was revealed that Upregulation of hsa_circ_0136666 promoted breast cancer progression by sponging miR-1299 and targeting CDK6.

Unraveling the South African Breast Cancer Story: The Relationship of Patients, Delay to Diagnosis, and Tumor Biology With Stage at Presentation in an Urban Setting

BACKGROUND

Adverse outcomes from breast cancer disproportionately affect women in sub-Saharan Africa, with delay the most studied contribution to advanced stage at presentation. However, tumor molecular biology and its contribution to advanced stage are yet to be explored.

MATERIALS AND METHODS

Patients newly diagnosed with breast cancer in a South African tertiary breast center completed a questionnaire and file review concerning socioeconomics, delay to care, stage at presentation, and molecular characteristics. Logistic regression was done to determine the relative risk of advanced stage presentation.

RESULTS

Advanced stage was present in 70.1% (n = 162) of the 231 participants, with 55.8% stage III (n = 129) and 32% (n = 72) having a T4 tumor. The median age was 56 y with 21.6% (n = 47) aged <45 y. Most common subtype was luminal B (57.7%, n = 128) followed by luminal A (21.6%, n = 48), triple negative (13.9%, n = 31), and HER2 positive (6.7%, n = 15). Lobular cancer (incidence risk ratio [IRR], 1.29; 95% confidence interval [CI], 1.03-1.62), high grade and intermediate grade tumors (IRR, 1.90; 95% CI, 1.15-3.13 and IRR, 1.95; 95% CI, 1.18-3.22, respectively), high Ki67 proliferation index (IRR, 1.30; 95% CI, 1.02-1.66), and HER2 overexpression (IRR, 1.32; 95% CI, 1.12-1.55) were more likely to present with advanced disease, as were luminal B (HER2+) cancers (adjusted IRR [aIRR], 1.46; 95% CI, 1.10-1.95). Although on univariate analysis Black and young participants were both more likely to have advanced stage (IRR, 1.23; 95% CI, 1.01-1.49 and IRR, 1.25; 95% CI, 1.04-1.51, respectively), in multivariate analysis controlling for tumor biology and delay, these were no longer significant (aIRR, 1.12; 95% CI, 0.91-1.37 and aIRR, 1.17; 95% CI, 0.94-1.48, respectively).

CONCLUSIONS

Tumor biology has a compelling role in the etiology of advanced-stage disease irrespective of socioeconomic factors. Accurate pathologic assessment is important in planning breast cancer care in Africa.

Aberrant promoter methylation of PCDH10 as a potential diagnostic and prognostic biomarker for patients with breast cancer

Protocadherin-10 (PCDH10) is a tumor suppressor gene. Its expression level is downregulated by promoter methylation in certain types of human tumors. The aim of the present study was to examine the expression level and promoter methylation status of PCDH10 in breast cancer cells and to evaluate the association of PCDH10 methylation and tumor progression and prognosis. MethyLight was used to detect the methylation status of PCDH10 in breast cancer tissues and healthy breast tissues. Reverse transcription-quantitative polymerase chain reaction was used to assess the mRNA expression level of PCDH10, as well as to evaluate the association between PCDH10 methylation and clinicopathological features, along with patients' overall survival (OS). PCDH10 5'-C-phosphate-G-3' (CpG) methylated sites were identified in tumor tissues and matched healthy tissues (n=392). Tumor tissues and matched healthy tissues exhibited identifiable PCR results, with PCDH10 gene promoter methylation identified in ductal carcinoma in situ (66%), invasive ductal carcinoma (82%), invasive ductal carcinoma with lymph node metastasis (85.32%) and hereditary breast cancer tissues (72.37%). PCDH10 mRNA expression was significantly decreased in breast cancer tissues compared with healthy breast tissues (P=0.032). PCDH10 methylation was associated with tumor size (P=0.004), but not associated with other clinical factors. Survival analysis revealed that the patients exhibiting methylated-PCDH10 had significantly poorer OS times than patients exhibiting unmethylated-PCDH10 (P<0.0001). Receiver operating characteristic analysis indicated a sensitivity of 75%, a specificity of 62.5%, and an area under the curve of 0.682 for PCDH10. Additionally, the results of the present study indicated that PCDH10 methylation status may be a useful diagnostic and prognostic evaluation biomarker for breast cancer. The results suggested that PCDH10 methylation is a common occurrence in primary breast cancer and is associated with poor survival rates among patients with breast cancer.

Ethnic disparities in breast cancer survival in New Zealand: which factors contribute?

Background

New Zealand has major ethnic disparities in breast cancer survival with Māori (indigenous people) and Pacific women (immigrants or descended from immigrants from Pacific Islands) faring much worse than other ethnic groups. This paper identified underlying factors and assessed their relative contribution to this risk differential.

Methods

This study involved all women who were diagnosed with primary invasive breast cancer in two health regions, covering about 40% of the national population, between January 2000 and June 2014. Māori and Pacific patients were compared with other ethnic groups in terms of demographics, mode of diagnosis, disease factors and treatment factors. Cox regression modelling was performed with stepwise adjustments, and hazards of excess mortality from breast cancer for Māori and Pacific patients were assessed.

Results

Of the 13,657 patients who were included in this analysis, 1281 (9.4%) were Māori, and 897 (6.6%) were Pacific women. Compared to other ethnic groups, they were younger, more likely to reside in deprived neighbourhoods and to have co-morbidities, and less likely to be diagnosed through screening and with early stage cancer, to be treated in a private care facility, to receive timely cancer treatment, and to receive breast conserving surgery. They had a higher risk of excess mortality from breast cancer (age and year of diagnosis adjusted hazard ratio: 1.76; 95% CI: 1.51–2.04 for Māori and 1.97; 95% CI: 1.67–2.32 for Pacific women), of which 75% and 99% respectively were explained by baseline differences. The most important contributor was late stage at diagnosis. Other contributors included neighbourhood deprivation, mode of diagnosis, type of health care facility where primary cancer treatment was undertaken and type of loco-regional therapy.

Conclusions

Late diagnosis, deprivation and differential access to and quality of cancer care services were the key contributors to ethnic disparities in breast cancer survival in New Zealand. Our findings underscore the need for a greater equity focus along the breast cancer care pathway, with an emphasis on improving access to early diagnosis for Māori and Pacific women.

Electronic supplementary material

The online version of this article (10.1186/s12885-017-3797-0) contains supplementary material, which is available to authorized users.

Circular RNA hsa_circ_0001982 Promotes Breast Cancer Cell Carcinogenesis Through Decreasing miR-143

Circular RNAs (circRNAs) are a type of noncoding RNAs generated from back-splicing, which have been verified to mediate multiple tumorigenesis. With the development of high-throughput sequencing, massive circRNAs are discovered in tumorous tissue. However, the potential physiological effect of circRNAs in breast cancer is still unknown. The purpose of this study is to investigate the expression profile of circRNA in breast cancer tissue and explore the in-depth regulatory mechanism in breast cancer tumorigenesis. In the present study, we screened the circRNA expression profiles in breast cancer tissue using circRNA microarray analysis. Totally 1705 circRNAs were identified to be significantly aberrant. Among these dysregulated circRNAs, hsa_circ_0001982 was markedly overexpressed in breast cancer tissue and cell lines. Bioinformatics analysis predicted that miR-143 acted as target of hsa_circ_0001982, which was confirmed by Dual-luciferase reporter assay. Loss-of-function and rescue experiments revealed that hsa_circ_0001982 knockdown suppressed breast cancer cell proliferation and invasion and induced apoptosis by targeting miR-143. In summary, our study preliminarily investigates the circRNA expression in breast cancer tissue and explores the role of competing endogenous RNA (ceRNA) mechanism in the progression, providing a novel insight for breast cancer tumorigenesis.