A ten-year monitoring of essential and non-essential elements in the dolphinfish Coryphaena hippurus from the southern Gulf of California

The concentrations of As, Cd, Cu, Pb and Zn were measured in muscle tissue of Coryphaena hippurus captured in the southern Gulf of California to determine inter-annual variations and their relation with environmental parameters for the period 2006-2015; additionally, health risk to consumers was assessed according to levels of studied elements and rate of fish consumption in northwest Mexico. During 2014 and 2015 the levels of As, Cd, Cu, and Zn were significantly lower than the rest of the years; in the case of As, it was also significantly lower in 2010. Oceanic Niño Index was negatively correlated with Zn concentrations in fish, while sea surface temperature was negatively correlated with Zn, Pb and Cd concentrations in dolphinfish. The simultaneous occurrence of the analyzed elements in muscle of dolphinfish indicated that health effects on consumers are not likely to occur; nevertheless, fishermen with elevated fish consumption might be at risk.

Dust-Metal Sources in an Urbanized Arid Zone: Implications for Health-Risk Assessments

The available information concerning metal pollution in different dust sources and the health effects in children remains limited in Mexico. This study focuses on Hermosillo, which is an urbanized area located in the Sonoran Desert in which soil resuspension and dust emission processes are common. The metal content of arsenic (As), chromium (Cr), manganese (Mn), and lead (Pb) were determined in three dust sources (playgrounds, roofs, and roads), each representing different exposure media (EM) for these elements. The metal levels in dust were found in the order of Mn > Cr > Pb > As with the highest metal content found in road dust. Despite the similar average metal distributions, principal component analysis shows a clear separation of the three EM with playground dust related to Cr and Mn and road dust to As and Pb. However, the geoaccumulation index results indicate that dust samples are uncontaminated to moderately polluted, except for Pb in road dust, which is considerably high. In addition, the enrichment factor suggests an anthropogenic origin for all of the studied metals except for Mn. In this context, the hazard index (HI) for noncarcinogenic risk is >1 in this population and thus represents a potential health risk. The spatial distribution for each metal on EM and the HI related to the marginality index could represent a more accurate decision-making tool in risk assessment studies.

Abstract B17: Family history of breast and ovarian cancer prevalence and its association with triple-negative subtype in Hispanic women

Background: A family history of breast cancer in a first-degree relative is an established risk factor for breast cancer; however, little is known about the profile of breast and ovarian family history in Hispanic/Latina women. Importance of this relates to recent reports showing a high prevalence of BRCA mutations in Hispanic/Latina women and a pattern of multiple recurrent mutations. In addition, less is known about the association of family history and tumor subtype in this growing ethnic group in the U.S.

Methods: Study participants included breast cancer patients of Mexican descent enrolled in the Ella Binational Breast Cancer Study. We first assessed the self-reported breast and ovarian family history profile in 1,150 women. Second, we compared differences in family history of breast and ovarian cancer prevalence between triple negative breast cancer (TNBC) and non-TNBC in 914 patients with available tumor subtype data. Logistic regression was conducted to compare odds of TNBC to non-TNBC according to family history of breast and ovarian cancer.

Results: Prevalence of breast cancer family history in a first- and first- or second-degree relative was 13.1% and 24.1%, respectively. A history of breast or ovarian cancer in first-degree relatives was reported in 14.9% of the women. After adjustment for age and country of residence, women with a first-degree relative with breast cancer were more likely to be diagnosed with TNBC compared to non-TNBC (OR=1.98; 95% CI, 1.26-3.11). The odds of TNBC compared to non-TNBC was 1.93 (95% CI, 1.26–2.97) for women with first-degree relatives with breast or ovarian cancer. There was a suggestion of stronger associations between family history and TNBC among women diagnosed at age <50 compared to those >50 years for breast cancer history in first-degree (P-interaction=0.14) and first- or second-degree relatives (P-interaction=0.07).

Conclusion: Findings suggest that familial cancers are associated with triple negative subtype, possibly related to the prevalence of BRCA mutations in Hispanic women, which are strongly associated with TNBC. Improvement in collection of family history through new tools and instruments targeting English- and Spanish-speaking Hispanic women should be a priority for future research. Identification of a strong family history can ultimately affect treatment plans, screening practices, and prevention options both for patients and their relatives.

Citation Format: Maria Elena Martinez, Kristin Anderson, Patricia Thompson, Betsy C. Wertheim, Lorena Martin, Ian Komenaka, Melissa Bondy, Adrian Daneri-Navarro, Maria Mercedes Meza-Montenegro, Luis Enrique Gutierrez-Millan, Abenaa Brewster, Lisa Madlensky, Malaika Tobias, Loki Natarajan. Family history of breast and ovarian cancer prevalence and its association with triple-negative subtype in Hispanic women. [abstract]. In: Proceedings of the Seventh AACR Conference on The Science of Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; Nov 9-12, 2014; San Antonio, TX. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2015;24(10 Suppl):Abstract nr B17.

Abstract B09: Acculturation, behavioral factors, and family history of breast cancer among Mexican and Mexican-American women

Introduction: Incidence rates for breast cancer are higher among Mexican-American (MA) women in the US than women living in Mexico. Studies have shown higher prevalence of breast cancer risk factors in higher vs. lower acculturated Hispanic/Latina women in the US. We compared the prevalence for behavioral risk factors and family history of breast cancer by level of acculturation and country of residence in women of Mexican descent.

Methods: Data were collected from 1,201 recently diagnosed breast cancer patients living in Mexico (n=581) and MAs in the US (n=620). MA participants were categorized into three acculturation groups (Spanish dominant, bilingual and English dominant) according to responses to an 8-item language acculturation scale, while women living in Mexico were used as the reference group. Prevalence of behavioral risk factors and family history of breast cancer were compared among the acculturation groups adjusting for age at diagnosis and education level.

Results: In the final adjusted models, bilingual and English-dominant MAs were significantly more likely to have a body mass index > 30 kg/m2, consume more than one alcoholic beverage a week, and report having a family history of breast cancer when compared to women living in Mexico. All three US acculturation groups were significantly more likely to have low total energy expenditure (<533 kcal/day) than women in Mexico. English-dominant women were significantly less likely to smoke cigarettes than the Mexican comparison group.

Conclusions: Our findings on acculturation and distributions of behavioral risk factors and family history of breast cancer add to the growing body of evidence suggesting acculturation has both positive and negative impacts on health behavior in Hispanic/Latino populations living in the US. Interventions and public health policies may benefit from considering these relationships when targeting health programs and campaigns to Mexican-American and Mexican women.

Citation Format: Jesse Nodora, Renee Cooper, Maria Elena Martinez, Gregory Talavera, Patricia Thompson, Ian Komenaka, Melissa Bondy, Abenaa Brewster, Adrian Daneri-Navarro, Maria Mercedes Meza-Montenegro, Luis Enrique Gutierrez-Millan. Acculturation, behavioral factors, and family history of breast cancer among Mexican and Mexican-American women. [abstract]. In: Proceedings of the Seventh AACR Conference on The Science of Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; Nov 9-12, 2014; San Antonio, TX. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2015;24(10 Suppl):Abstract nr B09.

Differentially expressed microRNAs in postpartum breast cancer in Hispanic women

The risk of breast cancer transiently increases immediately following pregnancy; peaking between 3-7 years. The biology that underlies this risk window and the effect on the natural history of the disease is unknown. MicroRNAs (miRNAs) are small non-coding RNAs that have been shown to be dysregulated in breast cancer. We conducted miRNA profiling of 56 tumors from a case series of multiparous Hispanic women and assessed the pattern of expression by time since last full-term pregnancy. A data-driven splitting analysis on the pattern of 355 miRNAs separated the case series into two groups: a) an early group representing women diagnosed with breast cancer ≤ 5.2 years postpartum (n = 12), and b) a late group representing women diagnosed with breast cancer ≥ 5.3 years postpartum (n = 44). We identified 15 miRNAs with significant differential expression between the early and late postpartum groups; 60% of these miRNAs are encoded on the X chromosome. Ten miRNAs had a two-fold or higher difference in expression with miR-138, miR-660, miR-31, miR-135b, miR-17, miR-454, and miR-934 overexpressed in the early versus the late group; while miR-892a, miR-199a-5p, and miR-542-5p were underexpressed in the early versus the late postpartum group. The DNA methylation of three out of five tested miRNAs (miR-31, miR-135b, and miR-138) was lower in the early versus late postpartum group, and negatively correlated with miRNA expression. Here we show that miRNAs are differentially expressed and differentially methylated between tumors of the early versus late postpartum, suggesting that potential differences in epigenetic dysfunction may be operative in postpartum breast cancers.

Family history of breast and ovarian cancer and triple negative subtype in hispanic/latina women

Familial breast and ovarian cancer prevalence was assessed among 1150 women of Mexican descent enrolled in a case-only, binational breast cancer study. Logistic regression was conducted to compare odds of triple negative breast cancer (TNBC) to non-TNBC according to family history of breast and breast or ovarian cancer among 914 of these women. Prevalence of breast cancer family history in a first- and first- or second-degree relative was 13.1% and 24.1%, respectively; that for breast or ovarian cancer in a first-degree relative was 14.9%. After adjustment for age and country of residence, women with a first-degree relative with breast cancer were more likely to be diagnosed with TNBC than non-TNBC (OR=1.98; 95% CI, 1.26-3.11). The odds of TNBC compared to non-TNBC were 1.93 (95% CI, 1.26-2.97) for women with a first-degree relative with breast or ovarian cancer. There were non-significant stronger associations between family history and TNBC among women diagnosed at age <50 compared to ≥50 years for breast cancer in a first-degree relative (P-interaction = 0.14) and a first- or second-degree relative (P-interaction = 0.07). Findings suggest that familial breast cancers are associated with triple negative subtype, possibly related to BRCA mutations in Hispanic/Latina women, which are strongly associated with TNBC. Family history is an important tool to identify Hispanic/Latina women who may be at increased risk of TNBC, and could benefit from prevention and early detection strategies.

Family history and breast cancer subtype among women of Mexican descent

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Background: A family history of breast cancer in a first-degree relative is associated with a 2-fold increase in breast cancer risk; however, breast cancer is a heterogeneous disease and there may be differences in risk profiles driven by tumor subtype or by racial/ethnic group. Methods: We assessed prevalence of familial breast cancer and its association with tumor subtype among 914 women with breast cancer of Mexican descent enrolled in the Ella Study, a case-only, binational (U.S.-Mexico) breast cancer study. Logistic regression was conducted to compare odds of triple negative breast cancers to non triple-negative breast cancers according to family history. Results: The prevalence of family history of breast cancer in a first- or second-degree relative was 24.1%, with 13.1% having an affected first-degree relative. Among participants who were diagnosed at age < 50, prevalence of family history of breast cancer in a first- or second-degree relative was 27.4%. After adjustment for age and country of residence, women with a first-degree relative with breast cancer were significantly more likely to be diagnosed with triple-negative breast cancers compared to non triple-negative breast cancers (OR = 1.98; 95% CI, 1.26-3.11). Similar results were seen for odds of triple-negative breast cancers compared to non-triple negative breast cancers for women with affected first- or second-degree relatives (OR=2.04; 95% CI, 1.40–2.98). The odds of triple-negative breast cancer compared to non-triple negative breast cancer was 1.93 (95% CI, 1.26–2.97) for women with first-degree relatives affected with breast or ovarian cancer. Conclusions: Findings suggest that familial cancers are most likely to be associated with triple negative subtype, supporting etiologic heterogeneity by tumor subtype in this population of Hispanic women. This association may be related to the prevalence of BRCA1 founder mutations in this population, which are strongly associated with triple-negative breast cancers. Identification of such differences in risk factors can help personalize screening and prevention approaches.

Association between parity and obesity in Mexican and Mexican-American women: findings from the Ella binational breast cancer study

Obesity at diagnosis of breast cancer is associated with higher all-cause mortality and treatment-associated toxicities. We evaluated the association between parity and obesity in the Ella study, a population of Mexican and Mexican-American breast cancer patients with high parity. Obesity outcomes included body mass index (BMI) ≥30 kg/m(2), waist circumference (WC) ≥35 in (88 cm), and waist-to-hip-ratio (WHR) ≥0.85. Prevalence of obesity ([BMI] ≥ 30 kg/m(2)) was 38.9 %. For WC, the multivariate odds ratio (OR) (95 % confidence interval [CI]) for having WC ≥ 35 inches in women with ≥4 pregnancies relative to those with 1-2 pregnancies was 1.59 (1.01-2.47). Higher parity (≥4 pregnancies) was non-significantly associated with high BMI (OR = 1.10; 95 % CI 0.73-1.67). No positive association was observed for WHR. Our results suggest WC is independently associated with high parity in Hispanic women and may be an optimal target for post-partum weight loss interventions.

Abstract B119: Presence of etiologic heterogeneity by breast tumor subtypes in Hispanic women with unique reproductive risk factor patterns

Background: Published data support the presence of etiologic heterogeneity by breast tumor subtype, but few studies have assessed this in Hispanic populations. Methods: We assessed tumor subtype prevalence and associations between reproductive factors and tumor subtypes in 1041 women of Mexican descent (559 U.S. and 482 Mexico) who participated in the Ella Binational Breast Cancer Study. Multinomial logistic regression comparing human epidermal growth factor receptor 2 positive tumors (HER2+, regardless of ER or PR status) and triple negative breast cancer (TNBC) to hormone receptor positive (HR+) tumors was conducted. Results: A higher proportion of ER- tumors was shown for women in Mexico (40.5%) vs. those in the U.S. (27.2%) and slightly higher proportions of HR+ (61.2% vs. 57.9%) and HER2+ (23.8% vs. 20.3%) tumors were observed in the U.S. compared to Mexico. Prevalence of TNBC was 16.7% overall; the percentage was higher for Mexican vs. U.S. women (19.5% vs. 14.5%). After adjustment for age and country of residence, compared to women with HR+ tumors, those with a later age at first pregnancy were significantly less likely to have TNBC (odds ratio [OR]=0.61; 95% confidence interval [CI]=0.39-0.95), whereas those with ≥ 3 full-term pregnancies were significantly more likely to have TNBC (OR=1.68; 95% CI=1.10-2.55). Patients who reported breastfeeding for &gt;12 months were over twice as likely to have TNBC than HR+ tumors (OR=2.14; 95% CI=1.24–3.68). A lower odds of TNBC was shown for longer menstruation duration, whether prior to first pregnancy (OR=0.78; 95% CI= 0.65–0.93 per 10 years) or prior to menopause (OR=0.79; 95% CI, 0.69–0.91 per 10 years). Associations comparing HER2+ to HR+ tumors were weak or non-existent except for the interval between last full-term pregnancy and breast cancer diagnosis. Conclusions: Findings show etiologic heterogeneity by tumor subtype in a population of Hispanic women with a unique reproductive profile. Given that Hispanic women have higher risk of breast cancer-specific mortality than non-Hispanic whites, our findings add to growing evidence of opposing effects of reproductive factors on breast tumor subtypes, which may partly explain disparities in outcomes.

Citation Format: Maria Elena Martinez, Betsy Wertheim, Loki Natarajan, Richard Schwab, Melissa Bondy, Adrian Daneri-Navarro, Maria Mercedes Meza-Montenegro, Luis Enrique Gutierrez-Millan, Abenaa Brewster, Ian K. Komenaka, Patricia A. Thompson. Presence of etiologic heterogeneity by breast tumor subtypes in Hispanic women with unique reproductive risk factor patterns. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Breast Cancer Research: Genetics, Biology, and Clinical Applications; Oct 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2013;11(10 Suppl):Abstract nr B119.

Reproductive factors, heterogeneity, and breast tumor subtypes in women of mexican descent

BACKGROUND

Published data support the presence of etiologic heterogeneity by breast tumor subtype, but few studies have assessed this in Hispanic populations.

METHODS

We assessed tumor subtype prevalence and associations between reproductive factors and tumor subtypes in 1,041 women of Mexican descent enrolled in a case-only, binational breast cancer study. Multinomial logistic regression comparing HER2(+) tumors and triple-negative breast cancer (TNBC) to luminal A tumors was conducted.

RESULTS

Compared with women with luminal A tumors, those with a later age at first pregnancy were less likely to have TNBC [OR, 0.61; 95% confidence interval (CI), 0.39-0.95], whereas those with three or more full-term pregnancies were more likely to have TNBC (OR, 1.68; 95% CI, 1.10-2.55). A lower odds of TNBC was shown for longer menstruation duration, whether before first pregnancy (OR, 0.78; 95% CI, 0.65-0.93 per 10 years) or menopause (OR, 0.79; 95% CI, 0.69-0.91 per 10 years). Patients who reported breastfeeding for more than 12 months were over twice as likely to have TNBC than luminal A tumors (OR, 2.14; 95% CI, 1.24-3.68). Associations comparing HER2(+) with luminal A tumors were weak or nonexistent except for the interval between last full-term pregnancy and breast cancer diagnosis.

CONCLUSIONS

Findings show etiologic heterogeneity by tumor subtype in a population of Hispanic women with unique reproductive profiles.

IMPACT

Identification of etiologically distinct breast tumor subtypes can further improve our understanding of the disease and help provide personalized prevention and treatment regimens.

Environmental arsenic exposure and serum matrix metalloproteinase-9

The objective of this study was to evaluate the relationship between environmental arsenic exposure and serum matrix metalloproteinase (MMP)-9, a biomarker associated with cardiovascular disease and cancer. In a cross-sectional study of residents of Arizona, USA (n=215) and Sonora, Mexico (n=163), drinking water was assayed for total arsenic, and daily drinking water arsenic intake was estimated. Urine was speciated for arsenic, and concentrations were adjusted for specific gravity. Serum was analyzed for MMP-9 using ELISA. Mixed model linear regression was used to assess the relation among drinking water arsenic concentration, drinking water arsenic intake, urinary arsenic sum of species (the sum of arsenite, arsenate, monomethylarsonic acid and dimethylarsinic acid), and MMP-9, controlling for autocorrelation within households. Drinking water arsenic concentration and intake were positively associated with MMP-9, both in crude analysis and after adjustment for gender, country/ethnicity, age, body mass index, current smoking, and diabetes. Urinary arsenic sum of species was positively associated with MMP-9 in multivariable analysis only. Using Akaike's Information Criterion, arsenic concentration in drinking water provided a better fitting model of MMP-9 than either urinary arsenic or drinking water arsenic intake. In conclusion, arsenic exposure evaluated using all three exposure metrics was positively associated with MMP-9.

Risk of recurrent Helicobacter pylori infection 1 year after initial eradication therapy in 7 Latin American communities

IMPORTANCE

The long-term effectiveness of Helicobacter pylori eradication programs for preventing gastric cancer will depend on recurrence risk and individual and community factors.

OBJECTIVE

To estimate risk of H. pylori recurrence and assess factors associated with successful eradication 1 year after treatment.

DESIGN, SETTING, AND PARTICIPANTS

Cohort analysis of 1463 randomized trial participants aged 21 to 65 years from 7 Latin American communities, who were treated for H. pylori and observed between September 2009 and July 2011.

INTERVENTIONS

Randomization to 1 of 3 treatment groups: 14-day lansoprazole, amoxicillin, and clarithromycin (triple therapy); 5-day lansoprazole and amoxicillin followed by 5-day lansoprazole, clarithromycin, and metronidazole (sequential); or 5-day lansoprazole, amoxicillin, clarithromycin, and metronidazole (concomitant). Participants with a positive (13)C-urea breath test (UBT) 6 to 8 weeks posttreatment were offered voluntary re-treatment with 14-day bismuth-based quadruple therapy.

MEASUREMENTS

Recurrent infection after a negative posttreatment UBT and factors associated with successful eradication at 1-year follow-up.

RESULTS

Among participants with UBT-negative results who had a 1-year follow-up UBT (n=1091), 125 tested UBT positive, a recurrence risk of 11.5% (95% CI, 9.6%-13.5%). Recurrence was significantly associated with study site (P = .03), nonadherence to initial therapy (adjusted odds ratio [AOR], 2.94; 95% CI, 1.31-6.13; P = .01), and children in the household (AOR, 1.17; 95% CI, 1.01-1.35 per child; P = .03). Of the 281 with positive posttreatment UBT results, 138 completed re-treatment, of whom 93 tested UBT negative at 1 year. Among the 1340 who had a 1-year UBT, 80.4% (95% CI, 76.4%-83.9%), 79.8% (95% CI, 75.8%-83.5%), and 77.8% (95% CI, 73.6%-81.6%) had UBT-negative results in the triple, sequential, and concomitant groups, respectively (P = .61), with 79.3% overall effectiveness (95% CI, 77.1%-81.5%). In a single-treatment course analysis that ignored the effects of re-treatment, the percentage of UBT-negative results at 1 year was 72.4% (95% CI, 69.9%-74.8%) and was significantly associated with study site (P < .001), adherence to initial therapy (AOR, 0.26; 95% CI, 0.15-0.42; P < .001), male sex (AOR, 1.63; 95% CI, 1.25-2.13; P < .001), and age (AOR, 1.14; 95% CI, 1.02-1.27 per decade; P = .02). One-year effectiveness among all 1463 enrolled participants, considering all missing UBT results as positive, was 72.7% (95% CI, 70.3%-74.9%).

CONCLUSIONS AND RELEVANCE

One year after treatment for H. pylori infection, recurrence occurred in 11.5% of participants who had negative posttreatment UBT results. Recurrence determinants (ie, nonadherence and demographics) may be as important as specific antibiotic regimen in determining the long-term success of H. pylori eradication interventions. Study findings are relevant to the feasibility of programs for the primary prevention of gastric cancer in high-incidence regions of Latin America.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01061437.

Residues of organochlorine pesticides in soils from the southern Sonora, Mexico

Although, the Yaqui and Mayo valleys are the most important agricultural areas in Sonora, there is only limited data of the pesticides residue in soils in these valleys. This study measured the organochlorine pesticides (OCPs) in 234 soil samples (residential and agricultural) from 24 communities. The global results (mean, range) indicated that benzene hexachloride (19.2, ND-938.5 μg g(-1)), endrin (6.6, ND-377.3 μg g(-1)) and DDTs (36.45, ND-679.7 μg g(-1)) were the dominant contaminants. Soil is one of the most important routes of exposure to OCPs in the population of southern Sonora and this study can be used to establish background levels of OCPs.

Abstract A89: HER2-overexpressing tumors and time since last pregnancy

Background: Risk of dying from breast cancer is higher among Hispanic women compared to non-Hispanic whites (NHW) despite lower overall incidence rates and a more favorable risk factor profile. Part of the observed disparity can be explained by aggressive tumor biology although unequal access to care is also a key factor. A recent pooled case-only study suggests Hispanic women are more likely to be diagnosed with HER2-positive tumors compared to NHWs. Given the high parity rates among Hispanics and recent interest in the differential effect of reproductive factors on breast tumor subtypes, we investigated the relative correlation between reproductive factors and tumor phenotype stratified on HER2 status.

Methods: A total of 459 women of Mexican origin from the case-only ELLA Binational Breast Cancer Study were classified into hormone receptor (HR) positive cases (estrogen or progesterone-receptor positive, HER2-negative) and HER2-overexpressing cases (HER2+, HR-). Women negative for all three markers (triple negative) were not considered in these analyses. Reproductive factors considered in the analysis include age at first full-term pregnancy, total number of full-term pregnancies, ever breastfeeding, breastfeeding after last pregnancy, and time since last pregnancy. Time to diagnosis since last pregnancy was classified as either ≤10 years or &gt;10 years. We conducted separate analyses for women diagnosed at ≤ 40 years (n=72) and at &gt;40 years of age (n=386). Differences were tested using a Pearson chi-square test or Student's t-test. We calculated case-case odds ratios (OR) and 95% confidence intervals (CI) using logistic regression to estimate the relative correlation between time since last pregnancy and HER2+ tumors in reference to HR+ tumors. Models included age at diagnosis, recruitment site, age at first pregnancy, number of pregnancies and breastfeeding.

Results: Out of 459 women, 338 (74%) were HR+ and 121 (26%) HER2+. No significant differences were observed in the proportion of HR+ tumors among women ≤ 40 and those &gt; 40 (79% vs. 73%, respectively; p=0.22). HER2+ cases were younger at diagnosis compared to HR+ cases (mean age 51.8 vs. 53.1, respectively; p= 0.30). HER2+ cases were more likely to be diagnosed after the age of 40 compared to HR+ cases (OR 4.37; 95% CI: 1.84,10.40) and were more likely to occur within the 10-year period following the last pregnancy (OR=3.99; 95% CI: 1.95,8.16). No difference was observed for age at first full-term pregnancy (OR 0.99; 95% CI: 0.95,1.03), number of full-term pregnancies (OR 0.95; 95% CI: 0.84,1.07) or ever breastfeeding (OR 0.98; 95% CI: 0.59,1.62). A significant interaction was observed between time since last pregnancy and age at diagnosis (p=0.03). Stratified results suggest the relationship between time since last pregnancy and tumor phenotype is stronger in the &gt;40 age group (OR 3.68; 95% CI: 1.60,8.44) compared to those ≤40 (OR 2.68; 95% CI: 0.19,37.16).

Conclusions: HER2+ tumors were more likely to be diagnosed in the 10-year period after the last pregnancy compared to HR+ tumors, independent of age. These findings suggest a relationship between HER2+ breast cancer and pregnancy history that differs from that with HR+ tumors, supporting the presence of etiologic heterogeneity in these subtypes.

Citation Information: Cancer Epidemiol Biomarkers Prev 2010;19(10 Suppl):A89.