Hisani N. Horne

Relationship of Terminal Duct Lobular Unit Involution of the Breast with Area and Volume Mammographic Densities

Elevated mammographic density (MD) is an established breast cancer risk factor. Reduced involution of terminal duct lobular units (TDLU), the histologic source of most breast cancers, has been associated with higher MD and breast cancer risk. We investigated relationships of TDLU involution with area and volumetric MD, measured throughout the breast and surrounding biopsy targets (perilesional). Three measures inversely related to TDLU involution (TDLU count/mm2, median TDLU span, median acini count/TDLU) assessed in benign diagnostic biopsies from 348 women, ages 40–65, were related to MD area (quantified with thresholding software) and volume (assessed with a density phantom) by analysis of covariance, stratified by menopausal status and adjusted for confounders. Among premenopausal women, TDLU count was directly associated with percent perilesional MD (P trend = 0.03), but not with absolute dense area/volume. Greater TDLU span was associated with elevated percent dense area/volume (P trend<0.05) and absolute perilesional MD (P = 0.003). Acini count was directly associated with absolute perilesional MD (P = 0.02). Greater TDLU involution (all metrics) was associated with increased nondense area/volume (P trend ≤ 0.04). Among postmenopausal women, TDLU measures were not significantly associated with MD. Among premenopausal women, reduced TDLU involution was associated with higher area and volumetric MD, particularly in perilesional parenchyma. Data indicating that TDLU involution and MD are correlated markers of breast cancer risk suggest that associations of MD with breast cancer may partly reflect amounts of at-risk epithelium. If confirmed, these results could suggest a prevention paradigm based on enhancing TDLU involution and monitoring efficacy by assessing MD reduction. Cancer Prev Res; 9(2); 149–58. ©2015 AACR.

Circulating insulin-like growth factor-I, insulin-like growth factor binding protein-3 and terminal duct lobular unit involution of the breast: a cross-sectional study of women with benign breast disease

BackgroundTerminal duct lobular units (TDLUs) are the primary structures from which breast cancers and their precursors arise. Decreased age-related TDLU involution and elevated mammographic density are both correlated and independently associated with increased breast cancer risk, suggesting that these characteristics of breast parenchyma might be linked to a common factor. Given data suggesting that increased circulating levels of insulin-like growth factors (IGFs) factors are related to reduced TDLU involution and increased mammographic density, we assessed these relationships using validated quantitative methods in a cross-sectional study of women with benign breast disease.MethodsSerum IGF-I, IGFBP-3 and IGF-I:IGFBP-3 molar ratios were measured in 228 women, ages 40-64, who underwent diagnostic breast biopsies yielding benign diagnoses at University of Vermont affiliated centers. Biopsies were assessed for three separate measures inversely related to TDLU involution: numbers of TDLUs per unit of tissue area (“TDLU count”), median TDLU diameter (“TDLU span”), and number of acini per TDLU (“acini count”). Regression models, stratified by menopausal status and adjusted for potential confounders, were used to assess the associations of TDLU count, median TDLU span and median acini count per TDLU with tertiles of circulating IGFs. Given that mammographic density is associated with both IGF levels and breast cancer risk, we also stratified these associations by mammographic density.ResultsHigher IGF-I levels among postmenopausal women and an elevated IGF-I:IGFBP-3 ratio among all women were associated with higher TDLU counts, a marker of decreased lobular involution (P-trend = 0.009 and <0.0001, respectively); these associations were strongest among women with elevated mammographic density (P-interaction <0.01). Circulating IGF levels were not significantly associated with TDLU span or acini count per TDLU.ConclusionsThese results suggest that elevated IGF levels may define a sub-group of women with high mammographic density and limited TDLU involution, two markers that have been related to increased breast cancer risk. If confirmed in prospective studies with cancer endpoints, these data may suggest that evaluation of IGF signaling and its downstream effects may have value for risk prediction and suggest strategies for breast cancer chemoprevention through inhibition of the IGF system.

Greater absolute risk for all subtypes of breast cancer in the US than Malaysia

Hormone receptor (HR) negative breast cancers are relatively more common in low-risk than high-risk countries and/or populations. However, the absolute variations between these different populations are not well established given the limited number of cancer registries with incidence rate data by breast cancer subtype. We, therefore, used two unique population-based resources with molecular data to compare incidence rates for the ‘intrinsic’ breast cancer subtypes between a low-risk Asian population in Malaysia and high-risk non-Hispanic white population in the National Cancer Institute’s surveillance, epidemiology, and end results 18 registries database (SEER 18). The intrinsic breast cancer subtypes were recapitulated with the joint expression of the HRs (estrogen receptor and progesterone receptor) and human epidermal growth factor receptor-2 (HER2). Invasive breast cancer incidence rates overall were fivefold greater in SEER 18 than in Malaysia. The majority of breast cancers were HR-positive in SEER 18 and HR-negative in Malaysia. Notwithstanding the greater relative distribution for HR-negative cancers in Malaysia, there was a greater absolute risk for all subtypes in SEER 18; incidence rates were nearly 7-fold higher for HR-positive and 2-fold higher for HR-negative cancers in SEER 18. Despite the well-established relative breast cancer differences between low-risk and high-risk countries and/or populations, there was a greater absolute risk for HR-positive and HR-negative subtypes in the US than Malaysia. Additional analytical studies are sorely needed to determine the factors responsible for the elevated risk of all subtypes of breast cancer in high-risk countries like the United States.

A robust association test for detecting genetic variants with heterogeneous effects.

One common strategy for detecting disease-associated genetic markers is to compare the genotype distributions between cases and controls, where cases have been diagnosed as having the disease condition. In a study of a complex disease with a heterogeneous etiology, the sampled case group most likely consists of people having different disease subtypes. If we conduct an association test by treating all cases as a single group, we maximize our chance of finding genetic risk factors with a homogeneous effect, regardless of the underlying disease etiology. However, this strategy might diminish the power for detecting risk factors whose effect size varies by disease subtype. We propose a robust statistical procedure to identify genetic risk factors that have either a uniform effect for all disease subtypes or heterogeneous effects across different subtypes, in situations where the subtypes are not predefined but can be characterized roughly by a set of clinical and/or pathologic markers. We demonstrate the advantage of the new procedure through numeric simulation studies and an application to a breast cancer study.

E-cadherin breast tumor expression, risk factors and survival: Pooled analysis of 5,933 cases from 12 studies in the Breast Cancer Association Consortium

E-cadherin (CDH1) is a putative tumor suppressor gene implicated in breast carcinogenesis. Yet, whether risk factors or survival differ by E-cadherin tumor expression is unclear. We evaluated E-cadherin tumor immunohistochemistry expression using tissue microarrays of 5,933 female invasive breast cancers from 12 studies from the Breast Cancer Consortium. H-scores were calculated and case-case odds ratios (OR) and 95% confidence intervals (CIs) were estimated using logistic regression. Survival analyses were performed using Cox regression models. All analyses were stratified by estrogen receptor (ER) status and histologic subtype. E-cadherin low cases (N = 1191, 20%) were more frequently of lobular histology, low grade, >2 cm, and HER2-negative. Loss of E-cadherin expression (score < 100) was associated with menopausal hormone use among ER-positive tumors (ever compared to never users, OR = 1.24, 95% CI = 0.97–1.59), which was stronger when we evaluated complete loss of E-cadherin (i.e. H-score = 0), OR = 1.57, 95% CI = 1.06–2.33. Breast cancer specific mortality was unrelated to E-cadherin expression in multivariable models. E-cadherin low expression is associated with lobular histology, tumor characteristics and menopausal hormone use, with no evidence of an association with breast cancer specific survival. These data support loss of E-cadherin expression as an important marker of tumor subtypes.

Serum insulin-like growth factor (IGF)-I and IGF binding protein-3 in relation to terminal duct lobular unit involution of the normal breast in Caucasian and African American women: The Susan G. Komen Tissue Bank

Lesser degrees of terminal duct lobular unit (TDLU) involution, as reflected by higher numbers of TDLUs and acini/TDLU, are associated with elevated breast cancer risk. In rodent models, the insulin‐like growth factor (IGF) system regulates involution of the mammary gland. We examined associations of circulating IGF measures with TDLU involution in normal breast tissues among women without precancerous lesions. Among 715 Caucasian and 283 African American (AA) women who donated normal breast tissue samples to the Komen Tissue Bank between 2009 and 2012 (75% premenopausal), serum concentrations of IGF‐I and binding protein (IGFBP)‐3 were quantified using enzyme‐linked immunosorbent assay. Hematoxilyn and eosin‐stained tissue sections were assessed for numbers of TDLUs (“TDLU count”). Zero‐inflated Poisson regression models with a robust variance estimator were used to estimate relative risks (RRs) for association of IGF measures (tertiles) with TDLU count by race and menopausal status, adjusting for potential confounders. AA (vs. Caucasian) women had higher age‐adjusted mean levels of serum IGF‐I (137 vs. 131 ng/mL, p = 0.07) and lower levels of IGFBP‐3 (4165 vs. 4684 ng/mL, p < 0.0001). Postmenopausal IGFBP‐3 was inversely associated with TDLU count among AA (RRT3vs.T1 = 0.49, 95% CI = 0.28–0.84, p‐trend = 0.04) and Caucasian (RRT3vs.T1=0.64, 95% CI = 0.42–0.98, p‐trend = 0.04) women. In premenopausal women, higher IGF‐I:IGFBP‐3 ratios were associated with higher TDLU count in Caucasian (RRT3vs.T1=1.33, 95% CI = 1.02–1.75, p‐trend = 0.04), but not in AA (RRT3vs.T1=0.65, 95% CI = 0.42–1.00, p‐trend = 0.05), women. Our data suggest a role of the IGF system, particularly IGFBP‐3, in TDLU involution of the normal breast, a breast cancer risk factor, among Caucasian and AA women.

Abstract 3451: Breast cancer risk factor associations by loss of E-cadherin tumor tissue expression: A pooled analysis of 5,896 cases in 12 studies from the Breast Cancer Association Consortium (BCAC)

Purpose: Expression of the tumor suppressor gene E-cadherin is diminished in lobular breast cancers and has been implicated in epithelial mesenchymal transition. We assessed risk factor associations for breast cancer stratified by low vs. high E-cadherin protein expression in a pooled analysis within the Breast Cancer Association Consortium (BCAC) studies. Methods: E-cadherin tumor tissue staining was performed centrally at the NCI on formalin-fixed paraffin-embedded tissue microarray (TMA) sections representing 6,010 breast cancer patients from 12 US and European BCAC studies. TMAs were digitally scanned and scored using the SlidePath Digital Image Hub (Leica Biosystems, Wetzlar, Germany). For 5,896 cancers with evaluable tumors, E-cadherin was visually scored as estimated percent of positive cells times stain intensity (0, 1+, 2+, 3+) (score range 0-300). E-cadherin low was defined as tumors with a score Results: E-cadherin low cancers comprised 20% of tumors and were associated with lobular histology, well/moderately differentiated cancers, > 2cm in size, and HER2-negative status (χ2, P Conclusion: This large pooled analysis shows that breast cancer risk factor associations may differ by E-cadherin expression independent of ER status, suggesting that it may represent a marker of etiologic heterogeneity. Citation Format: Hisani N. Horne, Hannah Oh, Mark E. Sherman, Maya Palakal, Stephen H. Hewitt, Marjanka Schmidt, Javier Benitez, Roger Milne, Hermann Brenner, Heli Nevanlinna, Arto Mannermaa, Georgia Chenevix-Trench, Fergus Couch, Peter Devilee, Diana Eccles, Maartje Hooning, Anthony J. Swerdlow, Nick Orr, Melissa A. Troester, Renata Cora, Paul D. Pharoah, Montserrat Garcia-Closas, Jonine D. Figueroa. Breast cancer risk factor associations by loss of E-cadherin tumor tissue expression: A pooled analysis of 5,896 cases in 12 studies from the Breast Cancer Association Consortium (BCAC). [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3451.

Abstract C81: Differences in breast cancer incidence and survival patterns by tumor subtype and ethnicity in Sarawak, Malaysia

Background: Breast cancer incidence is increasing rapidly among many Asian countries; however, population-based studies with the characterization of tumor subtypes in Asian populations are limited. The objective of this study was to evaluate differences in breast cancer incidence and survival by tumor subtype in an ethnically heterogeneous population in Sarawak, Malaysia. Methods: The analyses included a total of 1128 invasive breast cancer cases treated at Sarawak General Hospital from 1995 through 2009. As a comparison population, we used NCI9s Surveillance, Epidemiology, and End Results (SEER) 9-Registry Databases for breast cancer cases diagnosed during the years 1995 through 1999. Age-frequency density plots were constructed by estrogen receptor (ER) status, ethnicity, and molecular subtype in 1-year age increments. Differences in age at diagnosis between Chinese and non-Chinese participants were determined using Student9s t-tests, while differences in categorical tumor characteristics were examined using chi-square test. The Kaplan-Meier method and Cox proportional hazards model were used to assess relapse-free survival. Results: In the SEER population, ER-positive breast cancers showed a bimodal age distribution with a dominant late-onset, whereas ER-negative tumors had a predominantly early-onset mode. In contrast, the age distribution for the Malaysian women overall showed a predominantly early-onset mode at approximately 45 years, irrespective of ethnicity and/or tumor characteristic. However, compared to non-Chinese women, Chinese women had a slightly older age at diagnosis (median age at diagnosis 52.3 vs. 48.9; p Conclusion: There are distinct ethnic differences in prognosis and tumor subtypes among invasive breast cancer cases in Sarawak, Malaysia. Furthermore, the predominance of early-onset types of breast cancer suggest unique exposure patterns that promote aggressive breast cancer subtypes among all Malaysian women, specifically the non-Chinese group. Citation Format: Hisani N. Horne, C.R. Beena Devi, Tieng-Swee Tang, Stephen M. Hewitt, William F. Anderson, Xiaohong R. Yang. Differences in breast cancer incidence and survival patterns by tumor subtype and ethnicity in Sarawak, Malaysia. [abstract]. In: Proceedings of the Sixth AACR Conference: The Science of Cancer Health Disparities; Dec 6–9, 2013; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2014;23(11 Suppl):Abstract nr C81. doi:10.1158/1538-7755.DISP13-C81

Abstract LB-336: Association of variant rs2046210 at 6q25.1 (ESR1) with breast cancer risk suggests heterogeneity by E-cadherin tumor tissue expression

Proceedings: AACR 103rd Annual Meeting 2012‐‐ Mar 31‐Apr 4, 2012; Chicago, IL Background: E-cadherin is a cell-cell adhesion protein that functions as a cancer tumor suppressor gene based on in vitro and in vivo evidence showing that loss of this gene can lead to tumor progression and invasion. E-cadherin loss is strongly associated with breast tumors of lobular histology, which are more likely to be estrogen receptor-alpha (ESR1) positive and more frequently metastasize to the gastrointestinal tract and ovary compared to ductal tumors. We sought to determine if relative risk estimates for 19 established breast cancer susceptibility loci were modified by E-cadherin expression levels and tumor histology. Methods: Analyses included up to 1885 invasive breast cancer cases and 2366 age and site matched controls aged 20-74 years, from a population-based case-control study conducted in Poland from 2000-2003. Genotyping of the 19 single nucleotide polymorphisms (SNPs) was performed using TaqMan assays. Tissue expression of E-cadherin was assessed using immunohistochemical (IHC) staining of tissue microarrays and IHC results were scored as the product of percent positive tumor cells x intensity. Tumors with a score of <10 were classified as E-cadherin low and scores ≥10 as E-cadherin high. Polytomous logistic regression models adjusted for age and study site were used to estimate odds ratios (OR) and 95% confidence intervals (95% CI) for each breast cancer subtype, defined by E-cadherin expression levels, compared to controls. Logistic regression models restricted to cases were used to test for heterogeneity by tumor characteristics. Results: We observed significant associations with breast cancer risk overall for the following SNPs: 1p11.2 (NOTCH2/FCGR1B), 2q35 (TNP1/IGFBP5/IGFBP2/TNS1), 6q25.1 (ESR1), 8q24 (FAM84B/c-MYC/POU5F1P1), 9p21 (CDKN2B), 10p14 (CASP8), 10q21.2 (ZNF365), 10q26 (FGFR2), 11q13 (ORAOV1), 14q24.1 (RAD51L1) and two SNPs at 5p12 (MRPS30/FGFR10). One SNP rs2046210 at 6q25.1 (ESR1) displayed significant heterogeneity by E-cadherin expression after Bonferroni adjustment (Pheterogeneity= 0.002), showing stronger associations with breast tumors that had low E-cadherin expression levels compared to high. The estimated OR per A-allele for E-cadherin low (N = 136) tumors was 1.53 (95% CI = 1.19-1.98) and 0.99 for E-cadherin high tumors (N = 566) (95% CI = 0.86-1.14). These differences were not explained by lobular/ductal histology [per A-allele ORs (95% CI) for E-cadherin low lobular = 1.60 (1.15-2.22) and, for E-cadherin low ductal = 1.45 (0.88-2.40)] or ER status. Conclusions: Our data suggest that associations for breast cancer susceptibility loci vary by E-cadherin expression in breast cancer tumor tissues. Specifically, our results suggest that the genetic marker rs2046210 SNP at 6q25.1 may preferentially increase risk for tumors with low or absent E-cadherin expression, which requires replication in other datasets. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr LB-336. doi:1538-7445.AM2012-LB-336

Abstract P3-08-02: Common variants at 10p14 and 1p11.2 display heterogeneity in breast cancer associations by E-cadherin tumor tissue expression in two independent datasets

Background: E-cadherin is a tumor suppressor gene involved in cell-cell adhesion, epithelial-to-mesenchymal transitions (EMT) and invasion. Loss of E-cadherin expression is strongly associated with lobular breast cancers, which exhibit single cell patterns of infiltration and are often estrogen receptor positive. We sought to determine if relative risk estimates for 19 established breast cancer susceptibility loci were modified by E-cadherin breast tumor tissue expression. Methods: Case-control analyses included up to 1885 invasive breast cancer cases and 2366 age and site matched controls aged 20–74 years from the Polish Breast Cancer Study (PBCS), a population based case-control study conducted in Poland from 2000–2003. Genotyping of the 19 single nucleotide polymorphisms (SNPs) was performed using TaqMan® assays. Tissue expression of E-cadherin was assessed using immunohistochemical (IHC) staining of tissue microarrays and IHC results were scored as the product of percent positive tumor cells × intensity. Tumors having a score of Results: Three SNPs suggested significant heterogeneity by E-cadherin expression in the PBCS: rs2046210 at 6q25.1( ESR1 ) [per-allele ORs (95% CI); 1.53 (1.19–1.98) for E-cadherin low tumors and 0.99 (0.86–1.14) for E-cadherin high tumors, P-heterogeneity = 0.002]; rs1045485 at 10p14 ( CASP8 ) [per-allele ORs (95% CI); 0.62 (0.41–0.93) for E-cadherin low tumors and 0.98 (0.81–1.18) for E-cadherin high tumors, P-heterogeneity = 0.04]; and rs11249433 at 1p11.2 ( NOTCH2/FCGR1B ) [per-allele ORs (95% CI); 1.29 (1.02–1.64) for E-cadherin low tumors and 1.01 (0.88–1.15) for E-cadherin high tumors, P-heterogeneity = 0.06]. Combined case-only analysis of PBCS and SEARCH for these three SNPs showed significant heterogeneity by E-cadherin expression for rs11249433 [Interaction OR (95% CI); 1.19 (1.05–1.36), P-heterogeneity = 0.007] and rs1045485 [Interaction OR (95% CI); 0.69 (0.53–0.90), P-heterogeneity = 0.007]. The association with rs2046210 [Interaction OR (95% CI); 1.12 (0.61–2.03), P-heterogeneity = 0.73] did not remain significant in combined analyses. Conclusion: Our findings provide evidence that associations for breast cancer susceptibility loci vary by E-cadherin tumor tissue expression, which has not been described previously. Specifically, our results suggest that the genetic markers rs11249433 and rs1045485 may preferentially modify risk for tumors with low or absent E-cadherin expression in two independent data sets. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P3-08-02.