Breast cancer incidence and case fatality among 4.7 million women in relation to social and ethnic background: a population-based cohort study

TNA-Mediated Antisense Strategy to Knockdown Akt Genes for Triple-Negative Breast Cancer Therapy

Triple-negative breast cancer (TNBC) remains a significant challenge in terms of treatment, with limited efficacy of chemotherapy due to side effects and acquired drug resistance. In this study, a threose nucleic acid (TNA)-mediated antisense approach is employed to target therapeutic Akt genes for TNBC therapy. Specifically, two new TNA strands (anti-Akt2 and anti-Akt3) are designed and synthesized that specifically target Akt2 and Akt3 mRNAs. These TNAs exhibit exceptional enzymatic resistance, high specificity, enhance binding affinity with their target RNA molecules, and improve cellular uptake efficiency compared to natural nucleic acids. In both 2D and 3D TNBC cell models, the TNAs effectively inhibit the expression of their target mRNA and protein, surpassing the effects of scrambled TNAs. Moreover, when administered to TNBC-bearing animals in combination with lipid nanoparticles, the targeted anti-Akt TNAs lead to reduced tumor sizes and decreased target protein expression compared to control groups. Silencing the corresponding Akt genes also promotes apoptotic responses in TNBC and suppresses tumor cell proliferation in vivo. This study introduces a novel approach to TNBC therapy utilizing TNA polymers as antisense materials. Compared to conventional miRNA- and siRNA-based treatments, the TNA system holds promise as a cost-effective and scalable platform for TNBC treatment, owing to its remarkable enzymatic resistance, inexpensive synthetic reagents, and simple production procedures. It is anticipated that this TNA-based polymeric system, which targets anti-apoptotic proteins involved in breast tumor development and progression, can represent a significant advancement in the clinical development of effective antisense materials for TNBC, a cancer type that lacks effective targeted therapy.

Breast cancer-specific survival among immigrants and non-immigrants invited to BreastScreen Norway

Introduction

We have previously shown that immigrants have lower attendance in BreastScreen Norway than non-immigrants and that non-Western immigrants have lower incidence of breast cancer, but more advanced disease.

Purpose

To compare breast cancer-specific survival for immigrants versus non-immigrants diagnosed with screen-detected or symptomatic breast cancer.

Material and methods

We analyzed data from 28,320 women aged 50-69 diagnosed with breast cancer after being invited to BreastScreen Norway. We divided women into three groups; non-immigrants, immigrants from Western countries and immigrants from non-Western countries. We stratified our analyses according to detection mode (screen-detected breast cancer, interval cancer and cancer detected outside screening), and used cox regression to model the association between immigrants/non-immigrants and time to breast cancer death.

Results

Among screen-detected breast cancers, 28.7% were histologic grade 3 among immigrants from non-Western countries compared to 21.3% among non-immigrants. Interval cancers and cancers detected outside screening had larger tumor diameter and a higher percentage were histologic grade 3 and lymph node positive among immigrants from non-Western countries compared to non-immigrants. Hazard ratio (95% confidence interval) adjusted for age and year of diagnosis for time to breast cancer death compared to non-immigrants was 0.70 (0.39-1.27) for immigrants from Western countries and 0.52 (0.23-1.17) for immigrants from non-Western countries.

Conclusion

Despite more advanced histopathological tumor characteristics among immigrants from non-Western countries compared to non-immigrants, we did not observe statistically significant differences in breast-cancer specific survival between the two groups. Keeping in mind the low number of breast cancer deaths and possible overestimation of survival among immigrants, this might imply that equity in outcome can be achieved through adequate follow-up and treatment despite inequal access.

A population-based cohort study on changes in breast, lung and colorectal cancer incidence and mortality among non-Western immigrant women

BACKGROUND

Cancer risk varies geographically, and migrants are influenced by different risk factors before, during and after migration. Increased migration from non-Western countries to the Nordic countries calls for a better understanding of the migrants' cancer risk and the change in risk patterns over time. The aim of this study was to compare the incidence and mortality of breast, colorectal and lung cancer between non-Western immigrant and the native female population in Denmark, Finland, Iceland, and Norway.

MATERIAL AND METHODS

Data from national registries were processed and pre-analysed in each country. Multivariate Poisson regression models were used to model the relative differences in incidence and mortality as rate ratios (RR). The country-specific estimates and summary statistics were pooled together using a random effects model.

RESULTS

Non-Western immigrant women had significantly lower breast (RR 0.71, 0.65-0.78), colorectal (RR 0.72, 0.57-0.92) and lung (RR 0.55, 0.42-0.72) cancer incidence rates than native women, and the risk of these cancers among immigrant women increased with duration of residence. Differences were parallel in breast, colorectal and lung cancer mortality (RR 0.64, 0.55-0.74; RR 0.66, 0.48-0.92; RR 0.51, 0.34-0.79). Among immigrant women, higher education increased the risk for breast cancer and decreased it for lung cancer.

CONCLUSION

The results significantly complement and add to the previous findings of cancer burden and cancer burden transition among migrants and provide evidence of a prolonged cancer risk advantage among non-Western immigrant women. However, the findings show an increasing risk of lifestyle-related cancers with increasing duration of residence in the host country. Further studies are needed to discover underlying reasons for this phenomenon.

Geographically weighted linear combination test for gene-set analysis of a continuous spatial phenotype as applied to intratumor heterogeneity

Background: The impact of gene-sets on a spatial phenotype is not necessarily uniform across different locations of cancer tissue. This study introduces a computational platform, GWLCT, for combining gene set analysis with spatial data modeling to provide a new statistical test for location-specific association of phenotypes and molecular pathways in spatial single-cell RNA-seq data collected from an input tumor sample.

Methods: The main advantage of GWLCT consists of an analysis beyond global significance, allowing the association between the gene-set and the phenotype to vary across the tumor space. At each location, the most significant linear combination is found using a geographically weighted shrunken covariance matrix and kernel function. Whether a fixed or adaptive bandwidth is determined based on a cross-validation cross procedure. Our proposed method is compared to the global version of linear combination test (LCT), bulk and random-forest based gene-set enrichment analyses using data created by the Visium Spatial Gene Expression technique on an invasive breast cancer tissue sample, as well as 144 different simulation scenarios.

Results: In an illustrative example, the new geographically weighted linear combination test, GWLCT, identifies the cancer hallmark gene-sets that are significantly associated at each location with the five spatially continuous phenotypic contexts in the tumors defined by different well-known markers of cancer-associated fibroblasts. Scan statistics revealed clustering in the number of significant gene-sets. A spatial heatmap of combined significance over all selected gene-sets is also produced. Extensive simulation studies demonstrate that our proposed approach outperforms other methods in the considered scenarios, especially when the spatial association increases.

Conclusion: Our proposed approach considers the spatial covariance of gene expression to detect the most significant gene-sets affecting a continuous phenotype. It reveals spatially detailed information in tissue space and can thus play a key role in understanding the contextual heterogeneity of cancer cells.

More recent insights into the breast cancer burden across BRICS-Plus: Health consequences in key nations with emerging economies using the global burden of disease study 2019

Background

Brazil, Russia, India, China, South Africa, and 30 other Asian nations make up the BRICS-Plus, a group of developing countries that account for about half of the world's population and contribute significantly to the global illness burden. This study aimed to analyzed the epidemiological burden of female breast cancer (BC) across the BRICS-Plus from 1990 to 2019 and studied the associations with age, period, birth cohort and countries' sociodemographic index (SDI).

Methods

The BC mortality and incidence estimates came from the 2019 Global Burden of Disease Study. We estimated cohort and period effects in BC outcomes between 1990 and 2019 using age-period-cohort (APC) modeling. The maximum likelihood (ML) of the APC-model Poisson with log (Y) based on the natural-spline function was used to estimate the rate ratio (RR). We used annualized rate of change (AROC) to quantify change over the previous 30 years in BC across BRICS-Plus and compare it to the global.

Results

In 2019, there were about 1.98 million female BC cases (age-standardized rate of 45.86 [95% UI: 41.91, 49.76]) and 0.69 million deaths (age-standardized rate of 15.88 [95% UI: 14.66, 17.07]) around the globe. Among them, 45.4% of incident cases and 51.3% of deaths were attributed to the BRICS-Plus. China (41.1% cases and 26.5% deaths) and India (16.1% cases and 23.1% deaths) had the largest proportion of incident cases and deaths among the BRICS-Plus nations in 2019. Pakistan came in third with 5.6% cases and 8.8% deaths. Over the past three decades, from 1990 to 2019, the BRICS-Plus region's greatest AROC was seen in Lesotho (2.61%; 95%UI: 1.99-2.99). The birth cohort impacts on BC vary significantly among the BRICS-Plus nations. Overall, the risk of case-fatality rate tended to decline in all BRICS-Plus nations, notably in South Asian Association for Regional Cooperation (SAARC) and China-ASEAN Free Trade Area (China-ASEAN FTA) countries, and the drop in risk in the most recent cohort was lowest in China and the Maldives. Additionally, there was a substantial negative link between SDI and case fatality rate (r₁₉₉₀= -0.91, p<0.001; r₂₀₁₉= -0.89, p<0.001) in the BRICS-Plus in both 1990 and 2019, with the Eurasian Economic Union (EEU) nations having the highest case fatality rate.

Conclusions

The BC burden varies remarkably between different BRICS-Plus regions. Although the BRICS' efforts to regulate BC succeeded, the overall improvements lagged behind those in high-income Asia-Pacific nations. Every BRICS-Plus country should strengthen specific public health approaches and policies directed at different priority groups, according to BRIC-Plus and other high-burden nations.

Comparative docking analysis of tyrosine kinase inhibitors with HER2 and HER4 receptors

Tyrosine kinase receptors promote the growth and differentiation of normal breast and malignant human breast cancer cells, known as ERBB receptors. Various ERBB receptors are EGFR/ErbB1 and ErbB2/neu, which get over expressed in different solid tumors that activate upon binding of ligand to the extra cellular domain of these receptors. Of note, the epidermal growth factor receptor (EGFR) is a prime contributor to cancer through the involvement of four receptor tyrosine kinases (RTKs), namely, HER1, HER2, HER3, and HER4. Among them, HER2 and HER4 are majorly associated with breast cancer. Non-peptide quinazoline compounds homologous of the adenosine triphosphate (ATP) are competitively inhibited to RTKs to prevent cancer growth and metastasis. Various small drug molecule that targets the RTKs having the same scaffold, includes Lapatinib, Tivozanib, Erlotinib, Gefitinib, Crizotinib, and Ceritinib. The present study aims to investigate the comparative potential of structurally similar TKIs against HER2 and HER4 receptor receptors-silico molecular docking using FlexX software (LeadIT 2.3.2). Each docked complex's interaction profile was performed using BIOVIA Discovery Studio Visualizer 4.0. Molecular docking analysis was performed in order to get deeper insights into the interaction and binding pattern of the ligands with HER2 and HER4 receptors. The docking results revealed the Lapatinib compound acquired the relatively highest binding score of -32.36 kcal/mol and -35.76 kcal/mol with HER2 and HER4 proteins, respectively, concerning other compounds. Lapatinib is identified as a potential inhibitor for both the RTKs. Our study thus suggests the probable direction that could be further explored in inhibiting EGFR protein harboring breast cancer.

AGuIX nanoparticles enhance ionizing radiation-induced ferroptosis on tumor cells by targeting the NRF2-GPX4 signaling pathway

In the frame of radiotherapy treatment of cancer, radioresistance remains a major issue that still needs solutions to be overcome. To effectively improve the radiosensitivity of tumors and reduce the damage of radiation to neighboring normal tissues, radiosensitizers have been given increasing attention in recent years. As nanoparticles based on the metal element gadolinium, AGuIX nanoparticles have been shown to increase the radiosensitivity of cancers. Although it is a rare nanomaterial that has entered preclinical trials, the unclear biological mechanism hinders its further clinical application. In this study, we demonstrated the effectiveness of AGuIX nanoparticles in the radiosensitization of triple-negative breast cancer. We found that AGuIX nanoparticles increased the level of DNA damage by compromising the homologous recombination repair pathway instead of the non-homologous end joining pathway. Moreover, the results showed that AGuIX nanoparticles induced apoptosis, but the degree of apoptosis ability was very low, which cannot fully explain their strong radiosensitizing effect. Ferroptosis, the other mode of cell death, was also discovered to play a significant role in radiation sensitization, and AGuIX nanoparticles may regulate the anti-ferroptosis system by inhibiting the NRF2-GSH-GPX4 signaling pathway.

Epithelial-Mesenchymal Transition-Based Gene Signature and Distinct Molecular Subtypes for Predicting Clinical Outcomes in Breast Cancer

Purpose

Regulation of inducers and transcription factor families influence epithelial–mesenchymal transition (EMT), a contributing factor to breast cancer invasion and progression.

Methods

Molecular subtypes were classified based on EMT-related mRNAs using ConsensusClusterPlus package. Differences in tumor immune microenvironment and prognosis were assessed among subtypes. Based on EMT genes, a gene signature for prognosis was built using TCGA training set by performing multivariate and univariate Cox regression analyses. Prediction accuracy of the signature was validated by receiver operating characteristic (ROC) curves and overall survival analysis on internal and external datasets. By conducting univariate and multivariate Cox regression analyses, the risk signature as an independent prognostic indicator was assessed. A nomogram was constructed and validated by calibration analysis and decision curve analysis (DCA).

Results

Five molecular subtypes were characterized based on EMT genes. Patients in Cluster 2 exhibited an activated immune state and a better prognosis. An 11-EMT gene-signature was built to predict breast cancer prognosis. After validation, the signature showed independence and robustness in predicting clinical outcomes of patients. A nomogram combining the RiskScore and pTNM_stage accurately predicted 1-, 2-, 3-, and 5-year survival chance. In comparison with published model, the current model showed a higher area under the curve (AUC).

Conclusion

We characterized five breast cancer subtypes with distinct clinical outcomes and immune status. The study developed an 11-EMT gene-signature as an independent prognostic factor for predicting clinical outcomes of breast cancer.

The role of microRNA-4723-5p regulated by c-myc in triple-negative breast cancer

The aim of this study was to investigate the expression of miRNA regulated by c-myc and its mechanism in three negative breast cancer (TNBC). We constructed MDA-MB-231 cell line with low expression of c-myc by lentivirus short hairpin RNA (shRNA), analyzed the miRNA expression profile of MDA-MB-231 cell line with different expression levels of c-myc by high-throughput sequencing technology, obtained differential miRNA by bioinformatics analysis and statistical analysis, and verified hsa-mir-4723-5p by Quantitative Real-time polymerase chain reaction(QRT-PCR). The target gene of hsa-mir-4723-5p was analyzed by miRDB and miRWalk database. The results showed that there were significant differences in 126 miRNAs in c-myc knockdown cell lines compared with the control group, of which 84 were significantly up-regulated and 42 were significantly down regulated. According to the results of miRNA sequencing, the miRNA closely related to the expression of c-myc was hsa-mir-4723-5p. QRT PCR showed that the expression of hsa-mir-4723-5p was down regulated in TNBC cell line MDA-MB-231 with low expression of c-myc, which was positively correlated with the expression. The target genes of hsa-mir-4723-5p were predicted according to mirdb and mirwalk database. A total of 112 target genes were obtained, and 107 target genes were related to hsa-mir-4723-5p. Through mirdb and mirwalk databases, it was found that the target gene TRAF4 of hsa-mir-4723-5p may be related to cancer pathway and affect tumor metastasis. In conclusion, the hsa-miR-4723-5p regulated by c-myc may be involved.

Survival and Predictors of Mortality among Breast Cancer Patients in Northwest Ethiopia: A Retrospective Cohort Study

BACKGROUND

Breast cancer is the most common malignant tumor and the leading cause of cancer death in over 100 countries. Despite the high burden of difficulty, the survival status and the predictors for mortality are not yet determined in Ethiopia. Studies related to this area are scarce. Therefore, we aimed to estimate the survival status and predictors of mortality among breast cancer patients in Northwest Ethiopia.

METHODS

A retrospective cohort study design was carried out from September 2015 to August 2020 among 482 women who had breast cancer in Northwest Ethiopia. A systematic sampling technique was employed to select the required representative sample. The Cox regression model was used to identify the predictors of mortality among breast cancer patients.

RESULTS

For this study, 482 participants had followed for 8824 person-months total analysis time or at-risk time. In our findings, the overall survival of breast cancer patients at the end of two and five years was 54.24% and 25.8%, respectively. In the multivariable Cox regression model, age, stage of BC, menopausal status, and surgical therapy were significant predictors of death.

CONCLUSION

The overall survival after two years was 54.24%, and after five years was 25.8%. This result is lower than the recently published report and indicates that in LMIC, especially in rural cancer centers, the infrastructure and resources for routine screening mammography are often unavailable. Therefore, there is a need to promote early diagnosis of BC at each level of health-care delivery point.

An Assessment of Ovarian Cancer Histotypes Across the African Diaspora

OBJECTIVE

Ovarian cancer in Black women is common in many West African countries but is relatively rare in North America. Black women have worse survival outcomes when compared to White women. Ovarian cancer histotype, diagnosis, and age at presentation are known prognostic factors for outcome. We sought to conduct a preliminary comparative assessment of these factors across the African diaspora.

METHODS

Patients diagnosed with ovarian cancer (all histologies) between June 2016-December 2019 in Departments of Pathology at 25 participating sites in Nigeria were identified. Comparative population-based data, inclusive of Caribbean-born Blacks (CBB) and US-born Blacks (USB), were additionally captured from the International Agency for Research on Cancer and Florida Cancer Data Systems. Histology, country of birth, and age at diagnosis data were collected and evaluated across the three subgroups: USB, CBB and Nigerians. Statistical analyses were done using chi-square and student's t-test with significance set at p<0.05.

RESULTS

Nigerians had the highest proportion of germ cell tumor (GCT, 11.5%) and sex-cord stromal (SCST, 16.2%) ovarian cancers relative to CBB and USB (p=0.001). CBB (79.4%) and USB (77.3%) women were diagnosed with a larger proportion of serous ovarian cancer than Nigerians (60.4%) (p<0.0001). Nigerians were diagnosed with epithelial ovarian cancers at the youngest age (51.7± 12.8 years) relative to USB (58.9 ± 15.0) and CBB (59.0± 13.0,p<0.001). Black women [CBB (25.2 ± 15.0), Nigerians (29.5 ± 15.1), and USB (33.9 ± 17.9)] were diagnosed with GCT younger than White women (35.4 ± 20.5, p=0.011). Black women [Nigerians (47.5 ± 15.9), USB (50.9 ± 18.3) and CBB (50.9 ± 18.3)] were also diagnosed with SCST younger than White women (55.6 ± 16.5, p<0.01).

CONCLUSION

There is significant variation in age of diagnosis and distribution of ovarian cancer histotype/diagnosis across the African diaspora. The etiology of these findings requires further investigation.

Role of betulinic acid derivative SH-479 in triple negative breast cancer and bone microenvironment

Breast cancer has a high prevalence in the general population and is often associated with bone metastasis. Specific therapeutic targets are missing for triple negative breast cancer (TNBC), which presents some immunogenic characteristics. Betulinic acid (BA) has been reported to have some anti-tumor properties, and its modified derivative SH-479 was demonstrated to inhibit TNBC bone metastasis. The present study aimed to investigate the effect of the BA derivative SH-479 on breast cancer and bone microenvironment. The effect of BA and its derivative SH-479 on MDA-MB-231 cell proliferation was determined with the MTS method. The cytotoxicity effect of SH-479 was evaluated using the Live and Dead assay. Cell microfilament changes were observed by F-actin staining. The effects of SH-479 on PARP protein expression and cell cycle were detected by western blotting and flow cytometry, respectively. The migratory ability of breast cancer cells treated with SH-479 was determined by migration assay. The effect of SH-479 on osteoclast differentiation induced by breast cancer cells was observed using the osteoclast differentiation assay and tartrate-resistant acid phosphatase staining. The effects of SH-479 on T lymphocytes and bone marrow-derived suppressor cells (MDSCs) in bone marrow from mice were observed by flow cytometry. The results demonstrated that SH-479 significantly inhibited the proliferation of the TNBC cell line MDA-MB-231 at lower concentrations but had no significant effect on normal cells and other types of breast cancer cells for the same concentration. Furthermore, SH-479 significantly interfered with actin microfilaments in breast cancer cells but had no effect on cell apoptosis and cell cycle. In addition, SH-479 inhibited the migratory ability of breast cancer cells and the differentiation of osteoclasts induced by breast cancer cells. In bone marrow immune microenvironment, addition of SH-479 could promote the proliferation of CD4+T lymphocytes and inhibit the proliferation of MDSCs. Taken together, the findings from this study demonstrated that SH-479 inhibited the activity and migratory ability of TNBC cells and the differentiation of osteoclasts induced by TNBC and affected the bone marrow immune microenvironment. SH-479 may therefore inhibit breast cancer metastasis to bones, indicating that SH-479 may be considered as a promising drug to inhibit bone metastasis in patients with breast cancer.

Education level and breast cancer incidence: a meta-analysis of cohort studies

OBJECTIVE

We aimed to examine the association between education level and breast cancer incidence by a meta-analysis of cohort studies.

METHODS

Relevant studies were identified by searching PubMed, Web of Science, and Scopus databases on June 10, 2018. Reference lists from the obtained articles were also reviewed. We included cohort studies reporting relative risks with 95% CIs for the association between education level and breast cancer incidence. Either a fixed- or random-effects model was used to calculate the pooled risk estimates.

RESULTS

We identified 18 cohort studies with more than 10 million women. Compared with women with a lower education level, women with a higher education level had a significantly higher risk of developing breast cancer (pooled relative risk 1.22 [95% CI, 1.14-1.30]). The results did not differ by study area or reference group. The association remained in studies that adjusted for age at first birth and parity, but was attenuated and no longer significant when the analysis was restricted to studies that adjusted for alcohol use, to studies that adjusted for age at menopause, or to studies that adjusted for hormone therapy.

CONCLUSIONS

A higher education level may be associated with an increased risk of developing breast cancer, in which alcohol use, age at menopause, and hormone therapy may, at least partially, play a mediating role.

The impact of lifecourse socio-economic position and individual social mobility on breast cancer risk

BACKGROUND

Women with an advantaged socioeconomic position (SEP) have a higher risk of developing breast cancer (BC). The reasons for this association do not seem to be limited to reproductive factors and remain to be understood. We aimed to investigate the impact of lifecourse SEP from childhood and social mobility on the risk of BC considering a broad set of potential mediators.

METHODS

We used a discovery-replication strategy in two European prospective cohorts, E3N (N = 83,436) and EPIC-Italy (N = 20,530). In E3N, 7877 women were diagnosed with BC during a median 24.4 years of follow-up, while in EPIC-Italy, 893 BC cases were diagnosed within 15.1 years. Hazard ratios (HR) were estimated using Cox proportional hazard models on imputed data.

RESULTS

In E3N, women with higher education had a higher risk of BC (HR [95%CI] = 1.21 [1.12, 1.30]). This association was attenuated by adjusting for reproductive factors, in particular age at first childbirth (HR[95%CI] = 1.13 [1.04, 1.22]). Health behaviours, anthropometric variables, and BC screening had a weaker effect on the association. Women who remained in a stable advantaged SEP had a higher risk of BC (HR [95%CI] = 1.24 [1.07; 1.43]) attenuated after adjustment for potential mediators (HR [95%CI] = 1.13 [0.98; 1.31]). These results were replicated in EPIC-Italy.

CONCLUSIONS

These results confirm the important role of reproductive factors in the social gradient in BC risk, which does not appear to be fully explained by the large set of potential mediators, including cancer screening, suggesting that further research is needed to identify additional mechanisms.

Disparities in breast cancer stage at diagnosis between immigrant and native-born women: A meta-analysis

PURPOSE

To synthesize existing observational evidence to identify disparities in stage at breast cancer diagnosis between foreign- and native-born women. We hypothesized immigrant women would be less likely than natives to be diagnosed at a localized stage.

METHODS

Systematic searches for studies detailing stage at breast cancer diagnosis by birthplace in PubMed, Embase, and Web of Science yielded 11 relevant cohort studies from six countries. Odds ratios were pooled using random effects models.

RESULTS

Foreign-born women were 12% less likely to be diagnosed with breast cancer at a localized stage than natives (OR 0.88, 95% CI 0.82-0.95). A similar disadvantage was observed in immigrants from Asia, Eastern Europe, Latin America and the Caribbean, and developing or in transition nations; immigrants from developed countries experienced the least disparity.

CONCLUSIONS

This meta-analysis confirmed the presence of significant differences in breast cancer stage at diagnosis as per nativity. Across diverse immigrant groups and host countries, foreign-born women were significantly less likely to be diagnosed with localized breast cancer than native women; the magnitude of the disparity varied by region and economic condition of immigrants' birthplace.

Anticancer Activity of Tetrandrine by Inducing Apoptosis in Human Breast Cancer Cell Line MDA-MB-231 In Vivo

Tetrandrine (TET) is an alkaloid extracted from a traditional Chinese medicinal plant. It exerts remarkable anticancer activity and induces apoptotic cell death in various human cancer cells. The present study aimed to investigate the effects of TET on the inhibition of tumor growth and the induction of apoptosis in MDA-MB-231 breast cancer in xenograft mice. Tumor weight and volume were measured. The histopathological changes in the tumor tissue were observed. Immunohistochemistry analysis of Bcl-2-associated X protein (Bax) and B-cell lymphoma/leukemia-2 (Bcl-2) was carried out. The expression of apoptosis-associated genes and proteins, such as cysteine aspartic acid-specific protease-3 (Caspase-3), Survivin, Bax, Bcl-2, BH3-interacting domain death agonist (Bid), and poly ADP-ribose polymerase (PARP), was measured by reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting, respectively. TET inhibited tumor growth and induced apoptosis in TNBC cell line MDA-MB-231. The mechanism underlying this effect might be mediated by TET-upregulated Caspase-3, Bax, and Bid and downregulated by Bcl-2, Survivin, and PARP. Taken together, this study supported the fact that TET is a promising therapeutic agent for the treatment of TNBC, thereby providing experimental evidence for its use in the treatment of breast cancer.

Socioeconomic inequalities in cancer incidence in Europe: a comprehensive review of population-based epidemiological studies

Background

Since the end of the previous century, there has not been a comprehensive review of European studies on socioeconomic inequality in cancer incidence. In view of recent advances in data source linkage and analytical methods, we aimed to update the knowledge base on associations between location-specific cancer incidence and individual or area-level measures of socio-economic status (SES) among European adults.

Materials and methods

We systematically searched three databases (PubMed, Scopus and Web of Science) for articles on cancer incidence and SES. Qualitative synthesis was performed on the 91 included English language studies, published between 2000 and 2019 in Europe, which focused on adults, relied on cancer registry data and reported on relative risk (RR) estimates.

Results

Adults with low SES have increased risk of head and neck, oesophagogastric, liver and gallbladder, pancreatic, lung, kidney, bladder, penile and cervical cancers (highest RRs for lung, head and neck, stomach and cervix). Conversely, high SES is linked with increased risk of thyroid, breast, prostate and skin cancers. Central nervous system and haematological cancers are not associated with SES. The positive gap in testicular cancer has narrowed, while colorectal cancer shows a varying pattern in different countries. Negative associations are generally stronger for men compared to women.

Conclusions

In Europe, cancers in almost all common locations are associated with SES and the inequalities can be explained to a varying degree by known life-style related factors, most notably smoking. Independent effects of many individual and area SES measures which capture different aspects of SES can also be observed.

Dual-Blockade Immune Checkpoint for Breast Cancer Treatment Based on a Tumor-Penetrating Peptide Assembling Nanoparticle

Cancer immunotherapy can enhance the antitumor effect of drugs through a combinatorial approach in a synergistic manner. However, the effective targeted delivery of various drugs remains a challenge. We generated a peptide assembling tumor-targeted nanodelivery system based on a breast cancer homing and penetrating peptide for the codelivery of a programmed cell death ligand 1 (PD-L1) small interfering RNA (siRNA) (siPD-L1) and an indoleamine 2,3-dioxygenase inhibitor as a dual blockade of an immune checkpoint. The vector is capable of specifically accumulating in the breast cancer tumor site in a way that allows the siRNA to escape from endosomal vesicles after being endocytosed by tumor cells. The drug within these cells then acts to block tryptophan metabolism. The results showed that locally released siPD-L1 and 1-methyl-dl-tryptophan favor the survival and activation of cytotoxic T lymphocytes, resulting in apoptosis of breast cancer cells. Therefore, this study provides a potential approach for treating breast cancer by blocking immunological checkpoints through the assembly of micelles with functional peptides.

Breast cancer by migrant background in Belgium: Lower risk, but worse survival in women of non-European origin

Foreign and native populations differ in terms of breast cancer outcomes. Studies rarely distinguish between premenopausal and postmenopausal breast cancer, although the risk profile is different; nor between migrants of the first and second generation (FG and SG), which is crucial to examine genetic and environmental influences on breast cancer. This research fills these gaps by investigating patterns in breast cancer incidence and survival in different migrant groups by menopausal and migrant generational status, taking various risk factors into account. To this end, individually linked data from the 2001 census, the Belgian Cancer Registry and the Crossroads Bank for Social Security are used. Age-standardised incidence rates and incidence rate ratios are calculated by migrant background group, stratified according to ages 30-50 (premenopausal) and 50-70 (postmenopausal). Incidence rate ratios are examined with and without taking reproductive factors and socioeconomic position (SEP) into account. Relative survival percentages and relative excess risks of dying among premenopausal and postmenopausal patients are computed with and without controlling for the stage at diagnosis and SEP. Premenopausal breast cancer is further examined by migrant generational status. Breast cancer incidence is lower among non-European migrants compared to Belgians. Keeping SEP and known risk factors constant reduces much, but not all of the observed discrepancies. A risk convergence between SG migrants and Belgians for the development of premenopausal breast cancer is observed. Premenopausal breast cancer survival is worse among Moroccan patients due to a higher stage at diagnosis. This disadvantage is concentrated in the FG.

Gender, letters, relatives, and God: mediating actors in mammographic screening among Pakistani women in Norway

BACKGROUND

Pakistani immigrant women in Norway have lower attendance rates in the national breast cancer screening program (BreastScreen Norway) compared to non-immigrants and immigrants from most other countries.

PURPOSE

To identify and explore human and non-human actors that play a role for Pakistani immigrant women's attendance in the program.

MATERIAL AND METHODS

Qualitative interviews with 16 Norwegian-Pakistani women in 2017 and 2018. Inspired by Latour, we explored how human and non-human actors act and interact when Pakistani immigrant women consider attendance in BreastScreen Norway.

RESULTS

Among the actors found to play a significant role in the relationship between Pakistani immigrant women and the screening program were trust in the healthcare system and breast cancer screening, the gender of the screening radiographer, the written information received from the screening program, family life, daughters, general practitioners, non-governmental organizations, religious beliefs, private service providers, monetary expenses, accessibility, worries, and digital tools.

CONCLUSION

Many human and non-human actors work to shape and influence Pakistani immigrant women's screening attendance, or lack thereof, for instance by creating thoughts, promoting opportunities, raising doubts and generating worries, thus variously encouraging, enabling, facilitating, discouraging or preventing attendance in organized breast cancer screening.

Stroke and breast cancer in the United States during 2007-2017

Introduction

The main purpose of this work is to study the malignant neoplasms of the breast and the incidence of strokes in the United States and to find not only statistically significant predictors for cancer, but also a possible association between breast cancer and stroke.

Material and methods

The statistical methods used to derive the results of this work are χ² and one-way analysis of variance (ANOVA) tests, in order to check the statistical significance of breast cancer in relation to socio-economic factors of patients. In addition, a multivariate logistic regression analysis was used with the odds ratio (OR) to find statistically significant prognostic factors for breast cancer. The Pearson correlation coefficient was used to find the relationship between breast cancer and stroke.

Results

According to multiple logistic regression analysis, widowed women have 11 times higher risk developing breast cancer, while white women who are unemployed but have worked previously have two times higher risk for the occurrence of this type of cancer. In addition, a statistically significant relationship was found between the number of cases of breast cancer and stroke.

Conclusions

Our results describe for the first time the importance of deprivation (of work and partner) as a primary prognostic risk factor for cancer. Moreover, we found a link between breast cancer diagnosis and stroke.

Electro-Acupuncture Promotes Accumulation of Paclitaxel by Altering Tumor Microvasculature and Microenvironment in Breast Cancer of Mice

Targeted drug delivery could increase the efficacy of chemotherapy, however, a plethora of obstacles exist in the current targeted delivery designs. In this study, we introduce a novel avenue of targeted drug delivery using electro-acupuncture and evaluate its effect on the distribution of paclitaxel in a breast cancer mouse model. Our results show that electro-acupuncture intervention significantly increased the intratumoral concentration of paclitaxel. The mice in acupuncture group showed shorter t_max, longer t_1/2 and higher AUC of paclitaxel as compared with that in paclitaxel-only group. Moreover, we found that the acupuncture intervention significantly induced cell apoptosis in tumors. The levels of COL IV and α-SMA increased in tumors of acupuncture group. The negative tumor metastasis biomarker, NM23, was significantly upregulated in tumors of mice in acupuncture group. Our results suggest that acupuncture intervention around the tumor area increases the local concentration of chemotherapeutic agents. The targeted effect of acupuncture is achieved by altering tumor microvasculature and microenvironment. Therefore, combined therapy of acupuncture with chemotherapeutic agents is promising in improving cancer treatment efficacy.

Ecotropic virus integration-1 and calreticulin as novel prognostic markers in triple-negative breast cancer: A retrospective cohort study

Triple-negative breast cancer (TNBC) is an aggressive form of breast cancer, for which no specific targete d therapy is currently available. The present study aimed to examine the associations of ecotropic virus integration site 1 (EVI-1) and calreticulin (CRT) with other clinicopathological variables and the prognosis of patients with TNBC. The present retrospective cohort study reviewed the medical records of patients with TNBC treated in the Affiliated Hospitals of Jinzhou Medical University between January 2010 and June 2015. The protein expression levels of EVI-1 and CRT in tumor samples obtained from the patients were examined by immunohistochemical analysis. Univariate and multivariate regression analyses were used to identify associations between clinical characteristics and disease-free survival (DFS) or overall survival (OS). Kaplan-Meier analysis was performed to observe the survival condition (DFS/OS) according to EVI-1 and CRT expression. A total of 88 TNBC patients were included in the present study. Tumor tissues in 52 (59.1%) patients were EVI-1 positive, and tumor tissues in 64 (72.7%) patients were CRT-positive, and these rates were significantly higher compared with those in the corresponding paracancerous tissues (P<0.05). Multivariate analysis revealed that EVI-1 and CRT expression levels were independent variables associated with OS and DFS, and high expression of both CRT and EVI-1 was significantly associated with decreased OS and DFS compared with the other subgroups (low EVI-1/low CRT expression, low EVI-1/high CRT expression and high EVI-1/low CRT expression) of patients with TNBC. EVI-1 and CRT expression in TNBC was significantly correlated with poor outcome. Evaluation of the EVI-1 and CRT status may provide insight into prognosis prediction for patients with TNBC.

High-resolution imaging and single-cell analysis via laser ablation-inductively coupled plasma-mass spectrometry for the determination of membranous receptor expression levels in breast cancer cell lines using receptor-specific hybrid tracers

This work evaluates the possibility of placement of high-resolution imaging and single-cell analysis via laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) within precision medicine by assessing the suitability of LA-ICP-MS as a micro-analytical technique for the localization and quantification of membranous receptors in heterogeneous cell samples that express both the membrane-bound receptors C-X-C chemokine receptor type 4 (CXCR4) and epidermal growth factor receptor (EGFR). Staining of the breast cancer cell lines MDA-MB-231 X4 and MDA-MB-468 was achieved using receptor-specific hybrid tracers, containing both a fluorophore and a DTPA single-lanthanide chelate. Prior to LA-ICP-MS imaging, fluorescence confocal microscopy (FCM) imaging was performed to localize the receptors, hereby enabling direct comparison. Based on the different expression levels of CXCR4 and EGFR, a distinction could be made between the cell lines using both imaging modalities. Furthermore, FCM and LA-ICP-MS demonstrated complementary characteristics, as a more distinct discrimination could be made between both cell lines based on the EGFR-targeting hybrid tracer via LA-ICP-MS, due to the intrinsic CXCR4-related green fluorescent protein (GFP) signal present in the MDA-MB-231 X4 cells. Employing state-of-the-art LA-ICP-MS instrumentation in bidirectional area scanning mode for sub-cellular imaging of MDA-MB-231 X4 cells enabled the specific binding of the CXCR4-targeting hybrid tracer to the cell membrane to be clearly demonstrated. The stretching of cells over the glass substrate led to a considerably higher signal response for pixels at the cell edges, relative to the more central pixels. The determination of the expression levels of CXCR4 and EGFR for the MDA-MB-468 cell line was performed using LA-ICP-MS single-cell analysis (sc-LA-ICP-MS) and external calibration, based on the quantitative ablation of Ho-spiked dried gelatin droplet standards. Additionally, a second calibration approach was applied based on spot ablation of highly homogeneous dried gelatin gels in combination with the determination of the ablated volume using atomic force microscopy (AFM) and yielded results which were in good agreement with the expression levels determined via flow cytometry (FC) and mass cytometry (MC). Hybrid tracers enable a direct comparison between (i) FCM and LA-ICP-MS imaging for the evaluation of the microscopic binding pattern and between (ii) FC, MC and sc-LA-ICP-MS for the quantification of receptor expression levels in single cells.

Long non‑coding RNA UCA1 confers tamoxifen resistance in breast cancer endocrinotherapy through regulation of the EZH2/p21 axis and the PI3K/AKT signaling pathway

Tamoxifen is the gold standard for breast cancer endocrinotherapy. However, drug resistance remains a major limiting factor of tamoxifen treatment. Long non‑coding (lnc) RNA serves an important role in drug resistance; however, the molecular mechanisms of tamoxifen resistance in breast cancer endocrinotherapy are largely unclear. lncRNA urothelial cancer associated 1 (lncRNA UCA1, UCA1) has been proven to be dysregulated in human breast cancer and promotes cancer progression. In the present study, it was demonstrated that UCA1 was significantly upregulated in breast cancer tissues compared with healthy tissues. Furthermore, the expression level of UCA1 was significantly greater in tamoxifen‑resistant breast cancer cells (LCC2 and LCC9) when compared with those in the tamoxifen‑sensitive breast cancer cells (MCF‑7 and T47D). UCA1 silencing in LLC2 and LLC9 cells increased tamoxifen drug sensitivity by promoting cell apoptosis and arresting the cell cycle at the G2/M phase. Notably, the induced overexpression of UCA1 in MCF‑7 and T47D cells decreased the drug sensitivity of tamoxifen. The molecular mechanism involved in UCA1‑induced tamoxifen‑resistance was also investigated. It was identified that UCA1 was physically associated with the enhancer of zeste homolog 2 (EZH2), which suppressed the expression of p21 through histone methylation (H3K27me3) on the p21 promoter. In addition, it was demonstrated that UCA1 expression was paralleled to the phosphorylation of CAMP responsive element binding protein (CREB) and AKT. When LCC2 cells were treated with the phosphoinositide 3‑kinase (PI3K)/protein kinase B (AKT) signaling pathway inhibitor LY294002, the phosphorylation levels of CREB and AKT were significantly downregulated. Taken together, it was concluded that UCA1 regulates the EZH2/p21 axis and the PI3K/AKT signaling pathway in breast cancer, and may be a potential therapeutic target for solving tamoxifen resistance.

Sperm-associated antigen 5 is a potential biomarker for poor prognosis in breast cancer

Sperm-associated antigen 5 (SPAG5) is currently considered to serve a role in promoting tumor cell growth and is overexpressed in several types of human cancer. However, to the best of our knowledge, the association of SPAG5 with molecular subtypes of patients with breast cancer (BC) remains to be fully investigated. Reverse transcription-quantitative polymerase chain reaction and immunohistochemistry on tissue microarrays were used in the current study to detect the expression levels of SPAG5 mRNA and protein, respectively, in BC. The association between SPAG5 mRNA and protein levels, and clinical characteristics and prognostic information were investigated. SPAG5 mRNA and protein levels were identified to be higher in BC tissues compared with matched adjacent nontumor tissues. High expression level of SPAG5 protein was associated with tumor size, histological grade, estrogen receptor expression, Ki-67 expression, lymph node status, tumor-node-metastasis (TNM) stage and the triple-negative BC subtype. In addition, high expression level of SPAG5 protein was associated with a poor prognosis in patients with BC. In summary, the current study suggests that SPAG5 is a novel and useful prognostic biomarker in BC.

Baicalein induces apoptosis and autophagy of breast cancer cells via inhibiting PI3K/AKT pathway in vivo and vitro

Purpose

Baicalein, a widely used Chinese herbal medicine, has shown anticancer effects on many types of human cancer cell lines. However, little is known about the underlying mechanism in human breast cancer cells. In this study, we examined the apoptotic and autophagic pathways activated following baicalein treatment in human breast cancer cells in vitro and in vivo.

Materials and methods

In in vitro study, we used MTT and clone formation assay to confirm the inhibitory role of baicalein on proliferation of MCF-7 and MDA-MB-231 breast cancer cells. Apoptosis was detected employing Hoechst 33258 staining, JC-1 staining, and flow cytometry. Autophagy was monitored by acridine orange staining and transmission electron microscopy observation. Quantitative real-time PCR and Western blot analysis were employed to study the effects of baicalein on PI3K/AKT signaling components of MCF-7 and MDA-MB-231 breast cancer cells. In in vivo study, the effect of baicalein was tested with a breast cancer cells transplantation tumor model.

Results

Our study showed that baicalein has the potential to suppress cell proliferation, induce apoptosis and autophagy of breast cancer cells in vitro and in vivo. Furthermore, baicalein significantly downregulated the expression of p-AKT, p-mTOR, NF-κB, and p-IκB while enhancing the expression of IκB in MCF-7 and MDA-MB-231 cells. It also decreased the p-AKT/AKT and p-mTOR/mTOR ratios.

Conclusion

Our study demonstrated that baicalein induces apoptosis and autophagy of breast cancer cells via inhibiting the PI3K/AKT signaling pathway in vivo and vitro. Our study revealed that baicalein may be a potential therapeutic agent for breast cancer.

Mammographic screening attendance among immigrant and minority women: a systematic review and meta-analysis

Background Groups of immigrant and minority women are more often diagnosed with advanced stage breast cancer than other women. Mammographic screening aims to reduce mortality from breast cancer through early detection in asymptomatic women. Purpose To compare mammographic screening attendance among immigrant and minority women to that of other women. Material and Methods A literature search of PubMed, Embase, Google Scholar, and Cochrane identified 1369 papers published between January 1995 and March 2016. In the review, we included 33 studies investigating mammographic screening attendance among immigrant and/or minority women. In a meta-analysis, we included 19 of the studies that compared attendance among immigrant and/or minority women with that among other women, using a random effects model. Results The review included studies from Europe, North America, and Oceania, with 42,666,093 observations of opportunities for mammographic screening. Attendance was generally lower among immigrant and minority women compared to other women (46.2% vs. 55.0%; odds ratio = 0.64, 95% confidence interval = 0.56-0.73; P < 0.05, I²= 99.9%). Non-Western immigrants had lower attendance rates than other immigrants. Conclusion Immigrant and minority women had lower mammographic screening attendance than other women, which could potentially put them at increased risk for more advanced breast cancer. This review emphasizes the importance of continued efforts to engage with the preventative health needs of diverse populations in attempts to achieve equality in access to, and use of, care.

Fibronectin expression is upregulated by PI-3K/Akt activation in tamoxifen-resistant breast cancer cells

Fibronectin (FN) plays important roles in the EMT in a variety of cancer cell types. However, the mechanism by which FN expression is regulated in tamoxifen-resistant (TamR) breast cancer cells has not yet been fully elucidated. Aberrant FN expression was associated with poor prognosis in patients with luminal type A breast cancer. In addition, FN was upregulated in TamR cells. To investigate the mechanism by which FN expression is regulated, we assessed the levels of phosphorylated Akt, JNK, and STAT3 and found that they were all increased in TamR cells. Induction of FN expression was dampened by LY294002 or AKT IV in TamR cells. Furthermore, FN expression was increased by constitutively active (CA)-Akt overexpression in tamoxifen-sensitive MCF7 (TamS) cells and colony formation of TamR cells was blocked by AKT IV treatment. Taken together, these results demonstrate that FN expression is upregulated through the PI-3K/Akt pathway in tamoxifen-resistant breast cancer cells.

Isoharringtonine inhibits breast cancer stem-like properties and STAT3 signaling

OBJECTIVES

Breast cancer stem cells (BCSCs) contribute to breast cancer progression, relapse, and treatment resistance. Identification of the natural inhibitory components of BCSCs is therefore critical for clinical treatment. Here, we investigated whether isoharringtonine (IHT) had inhibitory effects on BCSCs in breast cancer cell lines.

METHODS

HCC1806, HCC1937, and MCF7 cells were treated with IHT. The proliferation and the migration of cells were detected by MTS assay and wound healing migration assay, respectively. The proportions of BCSCs were determined by flow cytometry and tumor sphere formation assay. Using real-time quantitative polymerase chain reaction (qRT-PCR) and Western blotting, the expression of Nanog and activation of STAT3 were detected, respectively.

RESULTS

Results showed that IHT inhibited the proliferation of HCC1806, HCC1937, and MCF-7 cells, and suppressed the migration of HCC1806 and HCC1937 cells in a dose-dependent manner. IHT treatment decreased the proportion of BCSCs in MCF-7, HCC1806, and HCC1937 cells. In addition, the mRNA level of Nanong was significantly downregulated after IHT treatment. We also found an inhibitory effect of IHT on STAT3 activation.

CONCLUSION

IHT inhibited the proliferation, migration, and BCSC proportion of breast cancer cell lines via inhibition of the STAT3/Nanong pathway.

The narrow treatment road to survival: Everyday life perspectives of women with breast cancer from Iraq and the former Yugoslavia undergoing radiation therapy in Sweden

This study aimed at exploring how women from Iraq and the former Yugoslavia, diagnosed with breast cancer and living in Sweden, experience their everyday life during radiation therapy. A qualitative research design was used comprising interviews with ten women, five originating from Iraq and five from the former Yugoslavia. Striving to survive, the women experienced their everyday life during radiation therapy as extremely challenging. This experience can be placed into three categories: strategies for survival, keeping up appearances and staying in control. Because of these specific challenges, immigrant women may need additional information and guidance in conjunction with the diagnosis, which may enable them to identify possible sources of support from those closest to them. Also, greater attention should focus on acknowledging the woman behind the diagnosis, regardless of her origin, to develop an individualised support programme to help her cope with everyday life during radiation therapy.

Lower attendance rates in immigrant versus non-immigrant women in the Norwegian Breast Cancer Screening Programme

Objective

The Norwegian Breast Cancer Screening Programme invites women aged 50–69 to biennial mammographic screening. Although 84% of invited women have attended at least once, attendance rates vary across the country. We investigated attendance rates among various immigrant groups compared with non-immigrants in the programme.

Methods

There were 4,053,691 invitations sent to 885,979 women between 1996 and 2015. Using individual level population-based data from the Cancer Registry and Statistics Norway, we examined percent attendance and calculated incidence rate ratios, comparing immigrants with non-immigrants, using Poisson regression, following women's first invitation to the programme and for ever having attended.

Results

Immigrant women had lower attendance rates than the rest of the population, both following the first invitation (53.1% versus 76.1%) and for ever having attended (66.9% versus 86.4%). Differences in attendance rates between non-immigrant and immigrant women were less pronounced, but still present, when adjusted for sociodemographic factors. We also identified differences in attendance between immigrant groups. Attendance increased with duration of residency in Norway. A subgroup analysis of migrants' daughters showed that 70.0% attended following the first invitation, while 82.3% had ever attended.

Conclusions

Immigrant women had lower breast cancer screening attendance rates. The rationale for immigrant women's non-attendance needs to be explored through further studies targeting women from various birth countries and regions.

Expression and Function of the Epidermal Growth Factor Receptor in Physiology and Disease

The epidermal growth factor receptor (EGFR) is the prototypical member of a family of membrane-associated intrinsic tyrosine kinase receptors, the ErbB family. EGFR is activated by multiple ligands, including EGF, transforming growth factor (TGF)-α, HB-EGF, betacellulin, amphiregulin, epiregulin, and epigen. EGFR is expressed in multiple organs and plays important roles in proliferation, survival, and differentiation in both development and normal physiology, as well as in pathophysiological conditions. In addition, EGFR transactivation underlies some important biologic consequences in response to many G protein-coupled receptor (GPCR) agonists. Aberrant EGFR activation is a significant factor in development and progression of multiple cancers, which has led to development of mechanism-based therapies with specific receptor antibodies and tyrosine kinase inhibitors. This review highlights the current knowledge about mechanisms and roles of EGFR in physiology and disease.

Socioeconomic inequalities in breast cancer incidence and mortality in Europe-a systematic review and meta-analysis

Background: Breast cancer is the leading cause of female cancer in Europe and is estimated to affect more than one in 10 women. Higher socioeconomic status has been linked to higher incidence but lower case fatality, while the impact on mortality is ambiguous. Methods: We performed a systematic literature review and meta-analysis on studies on association between socioeconomic status and breast cancer outcomes in Europe, with a focus on effects of confounding factors. Summary relative risks (SRRs) were calculated. Results: The systematic review included 25 articles of which 8 studied incidence, 10 case fatality and 8 mortality. The meta-analysis showed a significantly increased incidence (SRR 1.25, 1.17–1.32), a significantly decreased case fatality (SRR 0.72, 0.63–0.81) and a significantly increased mortality (SRR 1.16, 1.10–1.23) for women with higher socioeconomic status. The association for incidence became insignificant when reproductive factors were included. Case fatality remained significant after controlling for tumour characteristics, treatment factors, comorbidity and lifestyle factors. Mortality remained significant after controlling for reproductive factors. Conclusion: Women with higher socioeconomic status show significantly higher breast cancer incidence, which may be explained by reproductive factors, mammography screening, hormone replacement therapy and lifestyle factors. Lower case fatality for women with higher socioeconomic status may be partly explained by differences in tumour characteristics, treatment factors, comorbidity and lifestyle factors. Several factors linked to breast cancer risk and outcome, such as lower screening attendance for women with lower socioeconomic status, are suitable targets for policy intervention aimed at reducing socioeconomic-related inequalities in health outcomes.

Survival Analysis of Breast Cancer Patients after Surgery with an Intermediate Event: Application of Illness-Death Model

BACKGROUND

Breast cancer (BC) is the second most commonly diagnosed cancer after lung cancer. Survival of BC patients is affected by intermediate events. This study was aimed to investigate the disease course of primary nonmetastatic BC patients with first recurrence of the tumor (FRT) as the intermediate event using the illness- death model.

METHODS

This retrospective cohort study was conducted on 529 Iranian females with BC underwent surgery, from 1995 to 2013. Patients, tumor and treatment characteristics were collected from medical records of the patients. The illness-death model were used to investigate the relationship between these factors and survival time. Data were analyzed using version 3.1.1 of R software.

RESULTS

The risk of FRT in patients who had tumors size in the range of 2-5 cm and >5 cm was 1.3 and 3.5 times higher than that of patients with tumor size ≤2 cm, respectively (P<0.001). Furthermore, risk of death in patients aged ≥50 years was 1.6 times higher compared to patients aged less than 50 years (P =0.012). Risk of death after metastasis in patients with tumor size >5 cm was 2.1 times higher than patients with tumor size ≤2 cm (P =0.019).

CONCLUSIONS

The stage of the disease and tumor size have statistically significant effects on patients' survival before occurrence of the FRT. Furthermore, illness-death model was found to be a useful tool in modeling the disease course of BC patients.

Efficacy and mechanism of action of the tyrosine kinase inhibitors gefitinib, lapatinib and neratinib in the treatment of HER2-positive breast cancer: preclinical and clinical evidence

An increasing number of tumors, including breast cancer, overexpress proteins of the epidermal growth factor receptor (EGFR) family. The interaction between family members activates signaling pathways that promote tumor progression and resistance to treatment. Human epidermal growth factor receptor type II (HER2) positive breast cancer represents a clinical challenge for current therapy. It has motivated the development of novel and more effective therapeutic EGFR family target drugs, such as tyrosine kinase inhibitors (TKIs). This review focuses on the effects of three TKIs mostly studied in HER2- positive breast cancer, lapatinib, gefitinib and neratinib. Herein, we discuss the mechanism of action, therapeutic advantages and clinical applications of these TKIs. To date, TKIs seem to be promising therapeutic agents for the treatment of HER2-overexpressing breast tumors, either as monotherapy or combined with other pharmacological agents.

Patterns of changing cancer risks with time since diagnosis of a sibling

Family history is a well-known risk factor for many cancers. However, it is important to know if/how the familial risk of cancer changes over time. For each of four major cancers (colorectal, breast, prostate and melanoma), we identified siblings of cancer patients (case siblings) and siblings of matched cancer-free controls sampled from Swedish population-based registers. Effects of age and time since diagnosis on sibling risks were examined using Poisson regression and presented graphically as smoothed hazard ratios (HRs). Screening effects were investigated by comparing hazards before/after the introduction of mammography for breast cancer and prostate-specific antigen (PSA) testing for prostate cancer. Case siblings had higher cancer incidence than control siblings for all cancers at all ages, with overall incidence rate ratios (IRRs) of 2.41 (95% confidence interval 2.14-2.71) for colorectal cancer, 2.37 (2.24-2.52) for breast cancer, 3.69 (3.46-3.93) for prostate cancer and 3.20 (2.72-3.76) for melanoma. Risks were highest in siblings who were young when the first cancer was diagnosed in the family, with siblings aged 30-40 having IRR 9.05 (3.03-27.00) for colorectal cancer and 4.30 (2.87-6.45) for breast cancer. Smoothed HRs remained fairly constant for up to 20 years except for prostate cancer, where the HR decreased steeply during the first few years. After introduction of PSA testing, men had higher incidence of prostate cancer shortly after diagnosis in a brother, but no such screening effect was found for breast cancer. Our findings can help inform the screening and counseling of family members of cancer patients.

Analysing risk factors for poorer breast cancer outcomes in residents of lower socioeconomic areas of Australia

OBJECTIVE

To investigate patient, cancer and treatment factors associated with the residence of female breast cancer patients in lower socioeconomic areas of Australia to better understand factors that may contribute to their poorer cancer outcomes.

METHODS

Bivariable and multivariable analyses were performed using the Breast Quality Audit database of Breast Surgeons of Australia and New Zealand. RESULTS Multivariable regression indicated that patients from lower socioeconomic areas are more likely to live in more remote areas and to be treated at regional than major city centres. Although they appeared equally likely to be referred to surgeons from BreastScreen services as patients from higher socioeconomic areas, they were less likely to be referred as asymptomatic cases from other sources. In general, their cancer and treatment characteristics did not differ from those of women from higher socioeconomic areas, but ovarian ablation therapy was less common for these patients and bilateral synchronous lesions tended to be less frequent than for women from higher socioeconomic areas.

CONCLUSIONS

The results indicate that patients from lower socioeconomic areas are more likely to live in more remote districts and have their treatment in regional rather than major treatment centres. Their cancer and treatment characteristics appear to be similar to those of women from higher socioeconomic areas, although they are less likely to have ovarian ablation or to be referred as asymptomatic patients from sources other than BreastScreen. What is known about this topic? It is already known from Australian data that breast cancer outcomes are not as favourable for women from areas of socioeconomic disadvantage. The reasons for the poorer outcomes have not been understood. Studies in other countries have also found poorer outcomes in women from lower socioeconomic areas, and in some instances, have attributed this finding to more advanced stages of cancers at diagnosis and more limited treatment. The reasons are likely to vary with the country and health system characteristics. What does this paper add? The present study found that in Australia, women from lower socioeconomic areas do not have more advanced cancers at diagnosis, nor, in general, other cancer features that would predispose them to poorer outcomes. The standout differences were that they tended more to live in areas that were more remote from specialist metropolitan centres and were more likely to be treated in regional settings where prior research has indicated poorer outcomes. The reasons for these poorer outcomes are not known but may include lower levels of surgical specialisation, less access to specialised adjunctive services, and less involvement with multidisciplinary teams. Women from lower socioeconomic areas also appeared more likely to attend lower case load surgeons. Little difference was evident in the type of clinical care received, although women from lower socioeconomic areas were less likely to be asymptomatic referrals from other clinical settings (excluding BreastScreen). What are the implications for practitioners? Results suggest that poorer outcomes in women from lower socioeconomic areas in Australia may have less to do with the characteristics of their breast cancers or treatment modalities and more to do with health system features, such as access to specialist centres. This study highlights the importance of demographic and health system features as potentially key factors in service outcomes. Health system research should be strengthened in Australia to augment biomedical and clinical research, with a view to best meeting service needs of all sectors of the population.