Molecular Breast Cancer Subtypes in Premenopausal African-American Women, Tumor Biologic Factors and Clinical Outcome

Is early-onset cancer an emerging global epidemic? Current evidence and future implications

Over the past several decades, the incidence of early-onset cancers, often defined as cancers diagnosed in adults <50 years of age, in the breast, colorectum, endometrium, oesophagus, extrahepatic bile duct, gallbladder, head and neck, kidney, liver, bone marrow, pancreas, prostate, stomach and thyroid has increased in multiple countries. Increased use of screening programmes has contributed to this phenomenon to a certain extent, although a genuine increase in the incidence of early-onset forms of several cancer types also seems to have emerged. Evidence suggests an aetiological role of risk factor exposures in early life and young adulthood. Since the mid-20th century, substantial multigenerational changes in the exposome have occurred (including changes in diet, lifestyle, obesity, environment and the microbiome, all of which might interact with genomic and/or genetic susceptibilities). However, the effects of individual exposures remain largely unknown. To study early-life exposures and their implications for multiple cancer types will require prospective cohort studies with dedicated biobanking and data collection technologies. Raising awareness among both the public and health-care professionals will also be critical. In this Review, we describe changes in the incidence of early-onset cancers globally and suggest measures that are likely to reduce the burden of cancers and other chronic non-communicable diseases.

Predictors of Self-Reported Family Health History of Breast Cancer

The objective of this study was to identify predictors of self-reported family health history of breast cancer in an ethnically diverse population of women participating in a breast cancer screening program. Participants completed a self-administered questionnaire about their demography, health, breast health and family health history of breast cancer. The association between family health history of breast cancer and categorical variables were analyzed using the T test, chi square, and multi-nominal logistic regression. Those who were least likely to report a family history of cancer were African Americans (p = 0.02), and immigrant women from South America (p < 0.001) and Africa (p = 0.04). However, 34.4 % reported having a second-degree maternal relative with breast cancer compared to 6.9 % who reported having a second degree paternal relative with breast cancer. Therefore, there is a need to increase efforts to educate families about the importance of collecting and sharing one's family health history.

Cancer Hallmarks, Biomarkers and Breast Cancer Molecular Subtypes

Breast cancer is a complex disease encompassing multiple tumor entities, each characterized by distinct morphology, behavior and clinical implications. Besides estrogen receptor, progesterone receptor and human epidermal growth factor receptor 2, novel biomarkers have shown their prognostic and predictive values, complicating our understanding towards to the heterogeneity of such cancers. Ten cancer hallmarks have been proposed by Weinberg to characterize cancer and its carcinogenesis. By reviewing biomarkers and breast cancer molecular subtypes, we propose that the divergent outcome observed from patients stratified by hormone status are driven by different cancer hallmarks. 'Sustaining proliferative signaling' further differentiates cancers with positive hormone receptors. 'Activating invasion and metastasis' and 'evading immune destruction' drive the differentiation of triple negative breast cancers. 'Resisting cell death', 'genome instability and mutation' and 'deregulating cellular energetics' refine breast cancer classification with their predictive values. 'Evading growth suppressors', 'enabling replicative immortality', 'inducing angiogenesis' and 'tumor-promoting inflammation' have not been involved in breast cancer classification which need more focus in the future biomarker-related research. This review novels in its global view on breast cancer heterogeneity, which clarifies many confusions in this field and contributes to precision medicine.

Breast cancer in young women from a low risk population in Nepal

BACKGROUND

The overall incidence of breast cancer in South Asian countries, including Nepal, is low compared to Western countries. However, the incidence of breast cancer among young women is relatively high. Breast cancer in such cases is characterized by a relatively unfavorable prognosis and unusual pathological features. The aim of this study was to investigate clinico-pathological and biological characteristics in younger breast cancer patients (<40 years) and compare these with their older counterparts.

MATERIALS AND METHODS

Nine hundred and forty four consecutive female breast cancer patients, admitted to the Department of Surgery, Tribhuvan University Teaching Hospital, Kathmandu, Nepal between November 1997 and October 2012, were retrospectively analyzed.

RESULTS

Out of the 944 female breast cancer patients, 263 (27.9%) were <40 years. The mean age was 34.6 ± 5.0 years among younger patients compared to 54.1 ± 9.9 for those ≥ 40 years. The mean age at menarche was also significantly lower (13.5 ± 1.5 vs 14.2 ± 1.5 years p=0.001) while the mean duration of symptoms was significantly longer (7.6 vs 6.5 months p=0.004). Family history of breast cancer was evident in 3.0% of the young women versus 0.3% in the older one. Mammography was performed less frequently in younger patients (59.7%), compared to older (74.4%), and was of diagnostic benefit in only 20% of younger patients compared to 85% of older ones. At diagnosis, the mean tumor diameter was significantly larger in young women (5.0 ± 2.5 vs 4.5 ± 2.4 cm, p=0.005). Axillary lymph nodes were positive in 73% of younger patients and 59% of older patients. In the younger group, the proportion of stage III or IV disease was higher (55.1% vs 47.1%, p ≤ 0.05). The proportion of breast conserving surgery was higher in young patients (25.1% vs 8.7%) and a higher proportion of younger patients receive neoadjuvant chemotherapy (9.9% vs 2.8%). The most common histological type was ductal carcinoma (93.1% vs 86%). The proportion of histological grade II or III was higher in younger patients (55.9% vs 24.5%). Similarly, in the younger group, lymphatic and vascular invasion was more common (63.2% vs 34.3% and 39.8% vs 25.4%, respectively). Patients in the younger age group exhibited lower estrogen and/ or progesterone receptor positivity (34.7% vs 49.8%). Although statistically not significant, the proportion of triple negative tumors in younger age group was higher (22.4% vs 13.6%).

CONCLUSIONS

Breast cancer in young Nepalese women represents over one quarter of all female breast cancers, many being diagnosed at an advanced stage. Tumors in young women exhibit more aggressive biological features. Hence, breast cancer in young women is worth special attention for earlier detection.

Geographic differences in the distribution of molecular subtypes of breast cancer in Brazil

Background

To compare the distribution of the intrinsic molecular subtypes of breast cancer based on immunohistochemical profile in the five major geographic regions of Brazil, a country of continental dimension, with a wide racial variation of people.

Methods

The study was retrospective observational. We classified 5,687 invasive breast cancers by molecular subtype based on immunohistochemical expression of estrogen-receptor (ER), progesterone-receptor (PR), human epidermal growth factor receptor 2 (HER2), and Ki-67 proliferation index. Cases were classified as luminal A (ER and/or PR positive and HER2 negative, Ki-67 < 14%), luminal B (ER and/or PR positive, HER2 negative, and Ki-67 > 14%), triple-positive (ER and/or PR positive and HER2 positive), HER2-enriched (ER and PR negative, and HER2- positive), and triple-negative (TN) (ER negative, PR negative, and HER2- negative). Comparisons of the ages of patients and molecular subtypes between different geographic regions were performed.

Results

South and Southeast regions with a higher percentage of European ancestry and higher socioeconomic status presented with the highest proportion of luminal tumors. The North region presented with more aggressive subtypes (HER2-enriched and triple-negative), while the Central-West region predominated triple-positive carcinomas. The Northeast—a region with a high African influence—presented intermediate frequency of the different molecular subtypes. The differences persisted in subgroups of patients under and over 50 years.

Conclusions

The geographic regions differ according to the distribution of molecular subtypes of breast cancer. However, other differences, beside those related to African ancestry, such as socioeconomic, climatic, nutritional, and geographic, have to be considered to explain our results. The knowledge of the differences in breast cancer characteristics among the geographic regions may help to organize healthcare programs in large countries like Brazil with diverse economic and race composition among different geographic regions.

Prognostic and biological significance of proliferation and HER2 expression in the luminal class of breast cancer

The definition of Luminal-B subclass of breast cancer (BC) varies in literature. In this study, we have compared the proliferation status; assessed using KI67 labeling index (KI67-LI), and HER2-expression in estrogen receptor positive (ER+) BC to assess their impact on the biological and clinical characteristics of luminal-BC. 1547 (73.8 %) well-characterized clinically annotated stage I-III ER + BC were assessed for expression of KI67, HER2 (ASCO guidelines), and a large panel of relevant biomarkers (no = 37). 46.3 % of the cases show high KI67-LI (>13 %) and 8.4 % show HER2+ and both markers are positively associated with younger age, higher tumor grade and poorer outcome. High KI67-LI and HER2+ are associated with upregulation of ER-coactivators and proliferation-related markers and with downregulation of good prognostic markers. High KI67-LI is associated with larger size, advanced stage, and lymphovascular invasion (LVI) and with downregulation of luminal-enriched and DNA-damage repair markers. In contrast, HER2+ is associated with upregulation of ER-regulated proteins and E-cadherin. When analysis is restricted to high KI67-LI subgroup, HER2+ shows an association with upregulation of differentiation-associated proteins and E-cadherin. Conversely, within HER2+ class, high KI67-LI maintains its association with downregulation of differentiation-associated/luminal-enriched proteins. Outcome analyses indicate that both markers are independently associated with shorter survival but HER2+ is associated with a worse outcome. Although both are associated with high proliferation and poor prognosis within ER + BC, HER2+ is less frequent than high KI67-LI. Unlike KI67, HER2 seems to independently drive the aggressive behavior of ER+ tumors without downregulation of luminal proteins.

Family history of cancer associated with breast tumor clinicopathological features

Hereditary breast cancers have unique clinicopathological characteristics. Therefore, the objective of this study was to establish the relationship between self-reported family history of cancer and clinicopathological features in breast cancer patients from Washington, DC. Data on incident breast cancer cases from 2000 to 2010 were obtained from the Washington, DC Cancer Registry. Variables such as estrogen (ER), progesterone (PR), and human epidermal growth factor 2 (HER2) receptor status, as well as stage and grade, were analyzed in those that self-reported with (n = 1,734) and without a family history of cancer (n = 1,712). The breast cancer molecular subtypes were compared when ER, PR, and HER2 statuses were available. Furthermore, tumor characteristics were compared by race/ethnicity. Regression and chi-square analyses were performed. A report of family history was associated with age (OR = 1.27 95 % CI: 1.09-1.48; p < 0.0001), high grade tumors (OR = 1.29 95 % CI: 1.05-1.58; p = 0.02), and having ER and PR negative breast cancer (OR = 1.26 95 % CI: 1.02-1.57; p = 0.029). When tumor characteristics were compared by race/ethnicity, those that self-reported as African American with a family history had a higher frequency of ER negative tumors (OR = 1.51 95 % CI: 1.09-2.08; p = 0.008), PR negative tumors (OR = 1.46 95 % CI: 1.09-1.94; p = 0.028), grade 3 tumors (OR = 1.42 95 % CI: 1.05-1.93; p < 0.0001), and ER/PR negative tumors (OR = 1.5 95 % CI: 1.088-2.064; p = 0.01). These results suggest that a positive family history of cancer in African Americans should increase suspicions of hereditary cancer. Therefore, behavioral risk reduction activities, such as collecting a family history, may reduce late stage diagnosis and cancer mortality.

A Comparison of Tumor Biology in Primary Ductal Carcinoma In Situ Recurring as Invasive Carcinoma versus a New In Situ

Introduction. About half of all new ipsilateral events after a primary ductal carcinoma in situ (DCIS) are invasive carcinoma. We studied tumor markers in the primary DCIS in relation to type of event (invasive versus in situ). Methods. Two hundred and sixty-six women with a primary DCIS from two source populations, all with a known ipsilateral event, were included. All new events were regarded as recurrences. Patient and primary tumor characteristics (estrogen receptor (ER), progesterone receptor (PR), HER2, EGFR, and Ki67) were evaluated. Logistic regression was used to calculate odd ratios and 95% confidence intervals in univariate and multivariate analyses. Results. One hundred and thirty-six of the recurrences were invasive carcinoma and 130 were in situ. The recurrence was more often invasive if the primary DCIS was ER+ (OR 2.5, 95% CI 1.2–5.1). Primary DCIS being HER2+ (OR 0.5, 95% CI 0.3–0.9), EGFR+ (OR 0.4, 95% CI 0.2–0.9), and ER95−/HER2+ (OR 0.2, 95% CI 0.1–0.6) had a lower risk of a recurrence being invasive. Conclusions. In this study, comparing type of recurrence after a DCIS showed that the ER−/HER2+ tumors were related to a recurrence being a new DCIS. And surprisingly, tumors being ER+, HER2−, and EGFR− were related to a recurrence being invasive cancer.

A Population-Based Observational Study of First-Course Treatment and Survival for Adolescent and Young Adult Females with Breast Cancer

PURPOSE

Young age at breast cancer diagnosis is associated with poor survival. However, little is known about factors associated with first-course treatment receipt or survival among adolescent and young adult (AYA) females aged 15-39 years.

METHODS

Data regarding 19,906 eligible AYA breast cancers diagnosed in California during 1992-2009 were obtained from the population-based California Cancer Registry. Multivariable logistic regression was used to evaluate clinical and sociodemographic differences in treatment receipt. Multivariable Cox proportional hazards regression was used to examine differences in survival by initial treatment, and by patient and tumor characteristics.

RESULTS

Black and Hispanic AYAs diagnosed with in situ or stages I-III breast cancer were more likely than White AYAs to receive breast-conserving surgery (BCS) without radiation; Asian and Hispanic AYAs were more likely than Whites to receive mastectomy. Women in lower socioeconomic status (SES) neighborhoods were more likely to omit radiation after BCS, more likely to receive mastectomy, and less likely to receive chemotherapy, compared to those in higher SES neighborhoods. Among patients with invasive disease, survival improved an average of 5% per year during 1992-2009. AYAs who received BCS with radiation experienced better survival than other surgery/radiation options. Black AYAs had poorer survival than Whites. AYAs who resided in higher SES neighborhoods had better survival.

CONCLUSIONS

Treatment receipt among AYAs with breast cancer varied by race/ethnicity and neighborhood SES. Poor survival for Black AYAs and AYAs living in low SES neighborhoods in models adjusted for treatment receipt suggests that factors other than treatment may also be important to disease outcome.

Strong association of fascin expression with triple negative breast cancer and basal-like phenotype in African-American women

BACKGROUND

Fascin, an actin bundling protein, plays a critical role in cell motility due to formation of actin rich protrusions called filopodia, important in cell migration, invasion and metastatic spread. Fascin overexpression has been associated with epithelial to mesenchymal transition and correlates with progression and unfavourable prognosis in breast carcinoma.

OBJECTIVE

To evaluate fascin expression by immunohistochemistry and correlate the expression pattern with clinicopathological parameters in breast cancer in African-American (AA) women, in whom triple negative breast cancer (TNBC), an aggressive subtype, is more prevalent.

METHODS

Tissue microarrays were constructed from formalin-fixed, paraffin-embedded blocks of tumour tissue from primary breast carcinomas in 202 AA women. Immunohistochemical detection of fascin was correlated with four major subtypes of breast carcinoma (luminal A, luminal B, human epidermal growth factor receptor 2 and triple negative (TN)) and other clinicopathological factors, including age, grade, tumour size, stage, regional lymph node status and survival.

RESULTS

We observed a significant association between fascin expression and TN subtype, oestrogen receptor (ER) negativity, progesterone receptor (PR) negativity, Elston-Nottingham (EN) grade 3 and decreased overall survival. There was also a significant association between expression of CK 5/6, a marker of basal-like phenotype, and fascin expression.

CONCLUSION

These results suggest that fascin is a marker for TN subtype having a basal-like phenotype and decreased overall survival. Fascin may represent a target for therapy in TNBC in AA women.

Disparities in breast cancer outcomes between Caucasian and African American women: a model for describing the relationship of biological and nonbiological factors

Breast cancer is the most common malignancy in women in the United States but significant disparities exist for African American women compared to Caucasian women. African American women present with breast cancer at a younger age and with a greater incidence under the age of 50 years, develop histologically more aggressive tumors that are at a more advanced stage at presentation, and have a worse disease-free and overall survival than Caucasian women. The biological characteristics of the primary tumor play an important role in determining the outcome of the disparity, and significant differences have been identified between African American and Caucasian breast cancer in steroid receptor and growth factor receptor content, mutations in cell cycle components, chromosomal abnormalities, and tumor suppressor and other cancer genes. The consequences of the biological factors are influenced by a variety of nonbiological factors, including socioeconomic, health care access, reproductive, and confounding factors. The nonbiological factors may act directly to enhance (or inhibit) the consequences of the biological changes, indirectly to facilitate outcome of the disparity, or as a cofounding factor, driving the association between the biological factors and the disparity. The prevention and management of the disparities will require an understanding of the relationship of biological and nonbiological factors. The present review was undertaken to promote this understanding by describing the biological basis of the four major disparities - early age of onset, more advanced stage of disease, more aggressive histologic changes, and worse survival - and the important relationship to the nonbiological factors. A model is proposed to provide a comprehensive view of this relationship, with the goal of facilitating an understanding of each disparity and the issues that need to be addressed to eliminate the disparity.

Differential expression of breast cancer-associated genes between stage- and age-matched tumor specimens from African- and Caucasian-American Women diagnosed with breast cancer

Background

Recent studies suggest that the poorer breast cancer outcome observed in African-American women (AAW) may, in part, result from underlying molecular factors. The purpose of this study was to investigate gene expression differences between Caucasian-American women (CAW) and AAW that may contribute to this poorer prognosis.

Methods

The expression of 84 genes involved in breast carcinoma prognosis, response to therapy, estrogen signaling, and tumor aggressiveness was assessed in age- and stage-matched CAW and AAW paraffin-embedded breast cancer specimens. The Wilcoxon–Mann–Whitney Test was used to identify genes with a significant difference in expression between CAW and AAW. To determine if the differentially expressed genes could segregate between the CAW and AAW, we performed semi-supervised principal component analysis (SSPCA).

Results

Twenty genes were differentially expressed between AAW and CAW. SSPCA incorporating these 20 genes segregated AAW and CAW into two distinct groups. AAW were significantly (p < 0.05) more likely to display aberrations in G₁/S cell-cycle regulatory genes, decreased expression of cell-adhesion genes, and low to no expression of ESR1, PGR, ERBB2 and estrogen pathway targets.

Conclusions

The gene expression differences identified between AAW and CAW may contribute to more aggressive disease, resistance to therapy, enhanced metastatic potential and poor clinical outcome. These findings support the hypothesis that breast cancer specimens collected from AAW display distinct gene expression differences compared to similar tissues obtained from CAW. Additional population-based studies are necessary to determine if these gene expression variations contribute to the highly aggressive and treatment-resistant breast cancer phenotype frequently observed in AAW.

Dissecting the heterogeneity of triple-negative breast cancer

Triple-negative breast cancer (TNBC) accounts for 15% to 20% of breast cancers. It is a heterogeneous disease, not only on the molecular level, but also on the pathologic and clinical levels. TNBC is associated with a significantly higher probability of relapse and poorer overall survival in the first few years after diagnosis when compared with other breast cancer subtypes. This is observed despite its usual high sensitivity to chemotherapy. In the advanced setting, responses observed with chemotherapy lack durability. Early-stage clinical studies suggested impressive potential when a poly (ADP-ribose) polymerase (PARP) inhibitor is given for the treatment of advanced TNBC with BRCA gene dysfunction. The molecular complexity of TNBC has led to proposed subclassifications, which will be of great value for the development of targeted therapies. In this review, we discuss the biology of TNBC at the pathologic and the molecular levels. We also elaborate on the role of systemic therapies and the results of the first phase III clinical trial evaluating the addition of iniparib, a novel investigational anticancer agent that does not possess characteristics typical of the PARP inhibitor class, in combination with chemotherapy in advanced TNBC.

Prognostic significance of young age (<35 years) by subtype based on ER, PR, and HER2 status in breast cancer: a nationwide registry-based study

BACKGROUND

Young age is regarded as an adverse prognostic factor in patients with breast cancer, especially in those with a hormone receptor (HR)-positive tumor. We investigated the prognostic significance of an age of <35 years stratified by molecular subtype based on HR and HER2.

METHODS

Two large databases of Korean breast cancer patients, which included nationwide registry data, were analyzed.

RESULTS

In an analysis of 2,474 patients from the single institution, an age of <35 years was found to be an independent predictor of recurrence in patients with HR+/HER2- (hazard ratio 1.87; 95% confidence interval [CI]: 1.11-3.14; P=0.018), HR+/HER2+ (hazard ratio 3.09; 95% CI: 1.19-8.03; P=0.020), and HR-/HER2+ (hazard ratio 2.01; 95% CI: 1.03-3.92; P=0.040) subtypes, but not in those with the HR-/HER2- (triple-negative, TN) subtype (hazard ratio 1.08; 95% CI: 0.60-1.95; P=0.802). The results of an analysis of nationwide database data on 31,672 patients also showed that an age of <35 years significantly predicted poor cancer-specific survival in patients with HR+/HER2- (hazard ratio 3.40; 95% CI: 2.41-4.82; P<0.001), HR+/HER2+ (hazard ratio 1.96; 95% CI: 1.23-3.12; P=0.005), and HR-/HER2+ (hazard ratio 1.65; 95% CI: 1.07-2.52; P=0.022) subtypes, but again not in those with the TN subtype (hazard ratio 1.21; 95% CI: 0.88-1.67; P=0.240).

CONCLUSION

The prognostic significance of young age was found to depend on molecular subtype. An age of <35 years was a poor prognosticator in patients with the HR+/HER2-, HR+/HER2+, and HR-/HER2+ subtypes, but not in those with the TN subtype.

A review of the biological and clinical characteristics of luminal-like oestrogen receptor-positive breast cancer

Global gene expression profiling (GEP) studies of breast cancer have identified distinct biological classes with different clinical and therapeutic implications. Oestrogen receptor (ER) has been found to be a central marker of the molecular signature. GEP studies have consistently recognized a molecularly distinct class of tumours that is characterized by high-level expression of ER and other biomarkers recognized to be characteristic of normal luminal cells of the breast. This class is the largest of the GEP-defined molecular subclasses, comprising 60-70% of breast cancer cases. Moreover, it has been proposed that this group of tumours is composed of at least two subclasses distinguished by differing GEP profiles. At present, there is no consensus on the definition of the luminal subclasses and, in clinical practice, luminal-like tumours and ER-positive tumours are frequently considered to be the same. A better understanding of the biological features of luminal tumours could lead to their improved characterization and consistent identification. In this review, we explore the concept and definitions of the luminal-like class of breast carcinoma and their contribution to our understanding of their molecular features, clinical significance and therapeutic implications.

Genomic Grade Index: An important tool for assessing breast cancer tumor grade and prognosis

Different multi-gene expression signatures have been shown to outperform classic histopathologic variables and therefore represent an important step towards personalizing breast cancer treatment. In particular, gene profiles overcome many of the limitations observed with classic histopathologic variables. The Genomic Grade Index (GGI) is a gene expression signature developed to better define histologic grade assessment. GGI divides classic histologic grade into low and high risk, instead of grades 1, 2 and 3. The ability of GGI to predict response to chemotherapy and separate hormone receptor positive breast cancer subtypes has also been demonstrated. This article critically reviews the limitations inherent in classic histologic grade evaluation; it also reviews the process of gene signature development in general and then focuses on GGI, its biologic significance, comparison with different gene signatures, and its applicability to clinical practise.

Long-term survival of women with basal-like ductal carcinoma in situ of the breast: a population-based cohort study

BACKGROUND

Microarray gene-profiling of invasive breast cancer has identified different subtypes including luminal A, luminal B, HER2-overexpressing and basal-like groups. Basal-like invasive breast cancer is associated with a worse prognosis. However, the prognosis of basal-like ductal carcinoma in situ (DCIS) is still unknown. Our aim was to study the prognosis of basal-like DCIS in a large population-based cohort.

METHODS

All 458 women with a primary DCIS diagnosed between 1986 and 2004, in Uppland and Västmanland, Sweden were included. TMA blocks were constructed. To classify the DCIS tumors, we used immunohistochemical (IHC) markers (estrogen-, progesterone-, HER2, cytokeratin 5/6 and epidermal growth factor receptor) as a surrogate for the gene expression profiling. The association with prognosis was examined for basal-like DCIS and other subtypes using Kaplan-Meier survival analyses and Cox proportional hazards regression models.

RESULTS

IHC data were complete for 392 women. Thirty-two were basal-like (8.2%), 351 were luminal or HER2-positive (89.5%) and 9 unclassified (2.3%). Seventy-six women had a local recurrence of which 34 were invasive. Another 3 women had general metastases as first event. Basal-like DCIS showed a higher risk of local recurrence and invasive recurrence 1.8 (Confidence interval (CI) 95%, 0.8-4.2) and 1.9 (0.7-5.1), respectively. However, the difference was not statistically significant. Also, no statistically significant increased risk was seen for triple-negative or high grade DCIS.

CONCLUSIONS

Basal-like DCIS showed about a doubled, however not statistically significant risk for local recurrence and developing invasive cancer compared with the other molecular subtypes. Molecular subtyping was a better prognostic parameter than histopathological grade.

Analysing breast cancer microarrays from African Americans using shrinkage-based discriminant analysis

Breast cancer tumours among African Americans are usually more aggressive than those found in Caucasian populations. African-American patients with breast cancer also have higher mortality rates than Caucasian women. A better understanding of the disease aetiology of these breast cancers can help to improve and develop new methods for cancer prevention, diagnosis and treatment. The main goal of this project was to identify genes that help differentiate between oestrogen receptor-positive and -negative samples among a small group of African-American patients with breast cancer. Breast cancer microarrays from one of the largest genomic consortiums were analysed using 13 African-American and 201 Caucasian samples with oestrogen receptor status. We used a shrinkage-based classification method to identify genes that were informative in discriminating between oestrogen receptor-positive and -negative samples. Subset analysis and permutation were performed to obtain a set of genes unique to the African-American population. We identified a set of 156 probe sets, which gave a misclassification rate of 0.16 in distinguishing between oestrogen receptor-positive and -negative patients. The biological relevance of our findings was explored through literature-mining techniques and pathway mapping. An independent dataset was used to validate our findings and we found that the top ten genes mapped onto this dataset gave a misclassification rate of 0.15. The described method allows us best to utilise the information available from small sample size microarray data in the context of ethnic minorities.

Prognostic factors in young Japanese women with breast cancer: prognostic value of age at diagnosis

OBJECTIVE

The primary objective of this study was to verify whether breast cancer patients aged <35 at diagnosis have poorer prognoses than those aged 35-39, in other words, to identify the prognostic value of age in younger premenopausal patients under 40 years old. The secondary objective was to assess prognostic factors specific for younger premenopausal patients.

METHODS

We identified 242 consecutive patients who were diagnosed with stage I-III breast cancer before the age of 40 and underwent surgery between 1990 and 2004. We compared disease-free survival and overall survival in patients aged <35 years and those aged 35-39 years, and evaluated clinicopathological factors associated with disease-free survival or overall survival in each age group and in all patients under the age of 40.

RESULTS

Ninety-nine (41%) patients were younger than 35 years and 143 (59%) were between 35 and 39 years. No significant difference in disease-free survival or overall survival was found between the two groups. In our cohort of patients under the age of 40, the independent factors associated with poor disease-free survival and overall survival included positive axillary lymph nodes and triple-negative status, but not age at diagnosis. Adverse prognostic factors also did not differ considerably between the two age groups.

CONCLUSIONS

Age at diagnosis was not an independent prognostic factor in our study. Our findings suggest that other clinicopathological features rather than age should be used to determine individualized treatment courses for breast cancer patients younger than 40 years.

Pathologic complete response in breast cancer patients receiving anthracycline- and taxane-based neoadjuvant chemotherapy: evaluating the effect of race/ethnicity

BACKGROUND

The current study was conducted to evaluate the influence of race/ethnicity and tumor subtype in pathologic complete response (pCR) following treatment with neoadjuvant chemotherapy.

METHODS

A total of 2074 patients diagnosed with breast cancer between 1994 and 2008 who were treated with neoadjuvant anthracycline- and taxane-based chemotherapy were included. pCR was defined as no residual invasive cancer in the breast and axilla. The Kaplan-Meier product-limit was used to calculate survival outcomes. Cox proportional hazards models were fitted to determine the relationship of patient and tumor variables with outcome.

RESULTS

The median patient age was 50 years; 14.6% of patients were black, were 15.2% Hispanic, 64.3% were white, and 5.9% were of other race. There were no differences in pCR rates among race/ethnicity (12.3% in black, 14.2% in Hispanics, 12.3% in whites, and 11.5% in others, P = .788). Lack of pCR, breast cancer subtype, grade 3 tumors, and lymphovascular invasion were associated with worse recurrence-free survival (RFS) and overall survival (OS) (P </= .0001). Differences in RFS by race/ethnicity were noted in the patients with hormone receptor-positive disease (P = .007). On multivariate analysis, Hispanics had improved RFS (hazard ratio [HR], 0.69; 95% confidence interval [95% CI], 0.49-0.97) and OS (HR, 0.63; 95% CI, 0.41-0.97); blacks had a trend toward worse outcomes (RFS: HR, 1.28 [95% CI, 0.97-1.68] and OS: HR, 1.32 [95% CI, 0.97-1.81]) when compared with whites.

CONCLUSIONS

In this cohort of patients, race/ethnicity was not found to be significantly associated with pCR rates. On a multivariate analysis, improved outcomes were observed in Hispanics and a trend toward worse outcomes in black patients, when compared with white patients. Further research was needed to explore the potential differences in biology and outcomes.

Race and ethnicity and breast cancer outcomes in an underinsured population

BACKGROUND

The disparity in breast cancer mortality between African American women and non-Hispanic white women has been the subject of increased scrutiny. Few studies have addressed these differences in the setting of equal access to health care. We compared the breast cancer outcomes of underinsured African American and non-Hispanic white patients who were treated at a single institution.

METHODS

We conducted a retrospective review of medical records for breast cancer patients who were treated at Wishard Memorial Hospital from January 1, 1997, to February 28, 2006. A total of 574 patients (259 non-Hispanic whites and 315 African Americans) were evaluated. A Cox proportional hazards regression analysis for competing risks was performed. All statistical tests were two-sided.

RESULTS

Sociodemographic characteristics were similar in the two groups, and both racial groups were equally unlikely to have undergone screening mammography during the 2 years before diagnosis. Most (84%) of the patients were underinsured. The median time from diagnosis to operation, receipt of adequate surgery, and use of all types of adjuvant therapy were similar in the two groups. Median follow-up was 80.3 months for non-Hispanic whites and 77.9 months for African Americans. After accounting for the effect of comorbidities, African American race was statistically significantly associated with breast cancer-specific mortality (African Americans vs non-Hispanic whites: 26.0% vs 17.5%, P = .028; hazard ratio [HR] of death = 1.64, 95% confidence interval [CI] = 1.06 to 2.55). Adjustment for age at diagnosis, clinical stage, and hormone receptor status attenuated the effect, and the effect of race on breast cancer-specific survival was no longer statistically significant (HR of death from breast cancer = 1.43, 95% CI = 0.89 to 2.30). After adjustment for sociodemographic factors, the hazard ratio for race was further attenuated (HR = 1.26; 95% CI = 0.79 to 2.00).

CONCLUSIONS

In this underinsured population, African American patients had poorer breast cancer-specific survival than non-Hispanic white patients. After adjustment for clinical and sociodemographic factors, the effect of race on survival was no longer statistically significant.

Combinatorial biomarker expression in breast cancer

Current clinical management of breast cancer relies on the availability of robust clinicopathological variables and few well-defined biological markers. Recent microarray-based expression profiling studies have emphasised the importance of the molecular portraits of breast cancer and the possibility of classifying breast cancer into biologically and molecularly distinct groups. Subsequent large scale immunohistochemical studies have demonstrated that the added value of studying the molecular biomarker expression in combination rather than individually. Oestrogen (ER) and progesterone (PR) receptors and HER2 are currently used in routine pathological assessment of breast cancer. Additional biomarkers such as proliferation markers and 'basal' markers are likely to be included in the future. A better understanding of the prognostic and predictive value of combinatorial assessment of biomarker expression could lead to improved breast cancer management in routine clinical practice and would add to our knowledge concerning the variation in behaviour and response to therapy. Here, we review the evidence on the value of assessing biomarker expression in breast cancer individually and in combination and its relation to the recent molecular classification of breast cancer.

A case-control study of reproductive factors associated with subtypes of breast cancer in Northeast China

Based on the expression of estrogen receptor (ER), progesterone receptor (PR) and HER2/neu (HER2), breast cancer is classified into several subtypes: luminal A (ER+ and/or PR+, HER2-), luminal B (ER+ and/or PR+, HER2+), HER2-overexpressing (ER-, PR-, and HER2+) and triple-negative (ER-, PR-, and HER2-). The aim of this case-control study is to determine reproductive factors associated with breast cancer subtypes in Chinese women. A total of 1,417 patients diagnosed with breast cancer in the First Affiliated Hospital, China Medical University, Shenyang, China between 2001 and 2009 and 1,587 matched controls without a prior breast cancer were enrolled. Personal interviews were conducted to obtain information on reproductive characteristics and clinical history. Relationships between the factors and the subtypes of breast cancer were examined using logistic regression to compute odds ratios (OR) and 95% confidence intervals (CI). Notably, luminal A (50.0%) was the most prevalent subtype relative to luminal B (15.10%), HER2-overexpressing (10.87%) and triple-negative (23.08%). Menarche at an early age was associated with a reduced risk of luminal A (OR, 2.35; 95% CI, 1.45-3.81). Breastfeeding protected parous women from any subtype of breast cancer. Postmenopause and spontaneous abortion were inversely associated with the risk of luminal tumors. By contrast, multiparity, family history of breast cancer and induced abortion increased the risk of breast cancer. Collectively, our findings suggest that reproductive factors such as age at menarche, parity, breastfeeding, menopausal status and abortion history have different effects on the subtypes of breast cancer in Chinese women.

Possible Relationship between Basal-Like Breast Carcinoma and Age

SUMMARY: INTRODUCTION: Estrogen receptor expression is lower in breast carcinoma of women ≤45 years compared to women ≥65 years of age, which may imply a higher frequency of basal-like breast carcinomas in younger women. This study evaluated whether there is any difference in the frequency of basal-like phenotype and estrogen receptor (ER)-/HER2- invasive breast carcinomas between women of these 2 different age groups. PATIENTS AND METHODS: A total of 151 women aged ≤45 years or ≥65 years with invasive breast carcinomas were evaluated using tissue microarray, and classified into the following phenotypes: luminal A (ER+/HER2-), luminal B (ER+/HER2+), HER2 overexpression (ER-/HER2+), and basal-like (ER-/HER2- and expressing at least 1 of the basal markers p63, CK5 and/or P-cadherin). RESULTS: ER-/HER2- carcinomas were twice as frequent in women aged ≤45 years (p = 0.0247). However, when the basal-like phenotype was compared with all the other phenotypes grouped together, no statistically significant difference was found (p = 0.0854). CONCLUSIONS: ER-/HER2- carcinomas were more frequent in younger women compared to all the other phenotypes grouped together. An international consensus will be necessary to establish which markers should be used to define basal-like phenotype.