Abstract PR05: A genetic variant at 6q25 associated with estrogen receptor-negative breast cancer subtypes in Peruvian breast cancer patients

Background: We have previously identified a genetic variant, rs140068132, which has a strong protective effect on breast cancer risk. This variant is located near the estrogen receptor 1 gene (ESR1) on chromosome 6q25, a locus which has been repeatedly implicated in breast cancer risk. Women who carry two copies of the protective variant (GG) have 60-70% reduction in risk of developing breast cancer compared to women with none. The G variant has relatively high frequency in Latin American women (up to 23% in the 1000 Genomes Project Peruvians); it is only common in people of Indigenous American ancestry and almost absent in all other populations. We investigated whether the rs140068132-A/G polymorphism is associated with a specific breast cancer subtype among Peruvian women with breast cancer.

Methods: Blood samples and clinical data were collected from 441 women with breast cancer at the Instituto Nacional de Enfermedades Neoplasicas in Lima, Peru. Genotypic profiles were generated using the Affymetrix Precision Medicine Research Array. Four major breast cancer subtypes were identified based on immunohistochemical markers (luminal A, luminal B, triple-negative, and human epidermal growth factor receptor 2 (HER2) overexpressing). Quality control of the genotyped data was performed in PLINK. Genetic ancestry was determined for each individual using ADMIXTURE. ANOVAs were performed on the proportion of genetic ancestry and disease subtype. PLINK was used to perform a binary logistic regression on the rs140068132 variant and ER status (ER-negative versus-ER positive), with age and genetic ancestry as covariates.

Results: The breast cancer patients analyzed have the following average ancestry proportions: 77.3% Indigenous American, 17.4% European, 3.8% African and 1.5% East Asian. The frequency of the G allele in the Peruvian breast cancer patients is 14% (compared to 23% in healthy individuals from the 1000 Genomes Project). We found that the G allele of rs140068132 was associated with ER-negative status among cases (OR = 0.6443, P = 0.086) for both HER2 overexpressing and triple-negative. We also examined the proportions of ancestry in relation to subtypes of disease. The proportion of Indigenous American ancestry was associated with the HER2 overexpressing subtype (P = 0.06), with an average Indigenous American ancestry among these patients of 83.1% compared to 77.3% among all patients. The proportion of African ancestry was higher in women with the triple-negative subtype, with an average African ancestry of 4.8% among patients with the triple-negative subtype compared to a 3.8% average among all patients, but this trend was not statistically significant (P = 0.21).

Conclusions: The lower frequency of the variant in Peruvian breast cancer cases is consistent with a protective effect in this population. We have confirmed that the protective effect of the rs140068132 variant is stronger for ER-negative subtypes. Additional analyses are under way in a larger sample of Peruvian breast cancer patients.

This abstract is also being presented as Poster C051.

Citation Format: K.M. Marker, T. Vidaurre, L.I. Tamayo, J.N. Vásquez, R. Meza Florez, S. Casavilca, M. Calderon, J.E. Abugattas, H.L. Gómez, H.A. Fuentes, C.L. Monge Pimentel, S. Song, D. Cherry, S. Huntsman, D. Hu, E. Ziv, L. Fejerman. A genetic variant at 6q25 associated with estrogen receptor-negative breast cancer subtypes in Peruvian breast cancer patients [abstract]. In: Proceedings of the Eleventh AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2018 Nov 2-5; New Orleans, LA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl):Abstract nr PR05.

Abstract 4184: Tumor and risk factor characteristics among breast cancer patients from different geographic regions in Peru

There are few Latin American cohorts with available biospecimens that include women of high Indigenous American ancestry. The Peruvian population is characterized by a high degree of Native American (NA) ancestry, with this ancestral component varying between 56 to 100% on average, depending on the region. We have collected 1199 Peruvian samples from the Instituto Nacional de Enfermedades Neoplasicas in Lima. This cohort of patients represents a unique opportunity to study the molecular characteristics of breast cancer in the NA genetic and genomic background. Here we present a basic description of the women in the study and a comparison of tumor subtypes distribution and risk factor information of the patients by place of birth and residence.

We explored differences in tumor subtype distribution and risk factors in relation to place of birth or residence in the three main geographical region of Peru. To test differences in proportions we used Chi2 or Fisher-exact tests. To test differences in means for continuous variables we used ANOVA or t-tests. Genetic ancestry was estimated using genome wide genotypes and the program ADMIXTURE. Tumor subtypes were defined using the following criteria: ER+/PR+/HER2- as luminal A, ER+/PR+/HER2+ as luminal B, ER-/PR-/HER2+ as HER2+ and ER-/PR-/HER2- as triple negative.

Overall, the patients included in the study were relatively young (50 yrs, SD=11.0). The average number of full-term pregnancies was 3 (SD=1.8), the average age at first pregnancy 22 (SD=5.7) and age at menarche was 13 (SD=1.8). The tumor subtype distribution was 31% of Luminal B tumors, 24% luminal A, 12% HER2 and 12% triple negative and did not differ by place of birth or residence. We found that patients from the Coastal region were heavier and taller than those born in the Andean region (p<0.005). Women born in the Coastal region had the lowest age at menarche and a lower number of full-term pregnancies (p<0.0001). Similar trends were observed when we compared women by place of residence. Patients born in Lima, the Capital of Peru, smoke more (p<0.05), were heavier, had lower age at menarche, lower number of full term pregnancies and were diagnosed at a younger age, compared to women born outside the city (p<0.05). The distribution of NA genetic ancestry also varied by place of birth: patients born outside Lima had higher proportion of NA ancestry (78% SD=0.15 vs. 74%, SD=0.18, p<0.05).

The distribution of tumor subtypes among women in the Peruvian breast cancer cohort did not differ by place of birth or residence. However, we found that for some breast cancer risk factors, exposures differed between women from different regions. Finally, given the relatively low observed values for reproductive and lifestyle related exposures and the high proportion of Indigenous American ancestry of Peruvian women, this cohort is likely to be particularly informative to study genetic predisposition to breast cancer.

Citation Format: Valentina Zavala, Tatiana Vidaurre, Katie Marker, Jeannie Vásquez, L Tamayo, Renzo Florez, Sandro Casavilca, M Calderon, J Abugattas, H Gómez, H Fuentes, C Monge-Pimentel, S Song, D Cherry, Laura Fejerman. Tumor and risk factor characteristics among breast cancer patients from different geographic regions in Peru [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4184.

Barriers to enrollment in a state child health insurance program

OBJECTIVE

To identify barriers to enrollment into Colorado's Child Health Insurance Plan (CHP+) for non-Hispanic (NH), Hispanic (H), and uninsured families.

DESIGN

Telephone survey of 1) random samples of families who requested an application but did not complete it (N = 273 NH, N = 159 H) and 2) families with uninsured children identified by random-digit-dial statewide surveys (N = 165).

RESULTS

Major reasons for not enrolling included 1) got other insurance (NH 16.5%; H 27.2% P <.01), 2) thought household income was too high to qualify (NH 21.0%; H 11.9% P =.01), and 3) paperwork (NH 13.4%; H 14.7%, P = NS). Of those who thought their income was too high (N = 76, 17.6%), 58.5% appeared eligible based on reported income. Of uninsured families, only 41.7% had heard of CHP+. Of those who had never applied, major remediable reasons included not knowing enough about the program (20.9%) and thinking household income was too high (9.3%).

CONCLUSIONS

Effective marketing and education to increase awareness of CHP+ and ensure understanding of eligibility are critical to the success of the program.

A population based study of unintentional firearm fatalities

OBJECTIVES

To describe the circumstances of fatal unintentional firearm injuries in a statewide population in a region of the United States with high firearm fatality rates and to compare to similar data from an earlier period in the same state.

METHODS

Analyses of North Carolina medical examiner database (1985-94) and review of medical examiner case reports (1990-94) and comparison to similar data from 1979-82.

RESULTS

A total of 390 unintentional shooting deaths occurred (0.59/100,000 population) between 1985-94 with the highest rate in the ages 15-24. Between 1990-94, handguns were responsible for 59% of these deaths compared to 40% in the 1979-82 period. Younger victims were more likely to be shot by family or friends, though, 53% of all deaths were self inflicted. In 45 cases, the person firing the weapon was reported to believe that the gun was unloaded or had the safety device activated.

CONCLUSIONS

This study demonstrates changes in patterns of unintentional firearm fatalities in North Carolina in two decades, particularly the increase in incidence of events involving handguns. The results highlight the need for additional attention to efforts governing access to firearms, particularly handguns; technological advances in designing safer guns, and additional emphasis on safe storage policies and practices.

The 1996 Leicestershire Community Stroke & Ethnicity Study: differences and similarities between South Asian and white strokes

OBJECTIVE

To estimate the number of strokes in Leicestershire and investigate possible differences between South Asian and white patients.

DESIGN

Prospective incidence sample survey.

SETTING

Leicestershire.

PARTICIPANTS

Acute stroke cases occurring in registered populations of 12 'high Asian' and 11 'low Asian' general practices.

RESULTS

The age-specific incidence rates of stroke in Leicestershire were similar to those of the Oxford Community Stroke Project. South Asian patients were less likely to be living alone at home before their stroke and they tended to be younger than whites. However, only 12% of South Asian patients with a stroke were not admitted to hospital within 7 days of their stroke compared to 23% of white patients (chi2 = 3.24, d.f. = 1, P = 0.07). Only 21% of South Asian patients died within 28 days of their stroke compared to 33% of white patients (age-adjusted odds ratio = 0.37; 95% CI: 0.14-0.97).

CONCLUSIONS

Overlapping case-finding was crucial to finding all 'possible' strokes and this required close collaborative working between general practices, community health services, hospitals and the health authority. Relatively fewer South Asian patients were managed in the community in the first 7 days. Interestingly, South Asian patients were less likely than white patients to die within 28 days. This is an area worthy of further research.

Trends in nonfatal and fatal firearm-related injury rates in the United States, 1985-1995

STUDY OBJECTIVE

To characterize trends in annual estimates of nonfatal firearm-related injuries treated in US hospital emergency departments and to compare trends in quarterly rates of such injuries with those of firearm-related fatalities in the US population.

METHODS

Data on nonfatal firearm-related injuries were obtained from the National Electronic Injury Surveillance System (NEISS) by review of medical records for June 1, 1992, through May 31, 1995. Data on firearm-related fatalities were obtained from the National Vital Statistics System for January 1, 1985, through December 31, 1995. NEISS comprises 91 hospitals that represent a stratified probability sample of all hospitals in the United States and its territories that have at least six beds and provide 24-hour emergency service. The main outcome measures were numbers, percentages, and quarterly population rates for nonfatal and fatal firearm-related injuries.

RESULTS

An estimated 288,538 nonfatal firearm-related injuries (95% confidence interval [CI], 169,776 to 407,300) were treated in EDs during the 3-year study period. The annual number of non-fatal firearm-related injuries increased from 99,025 for June 1992 through May 1993 (95% CI, 58,266 to 139,784) to 101,669 for June 1993 through May 1994 (95% CI, 59,822 to 143,516), then decreased to 87,844 for June 1994 through May 1995 (95% CI, 51,687 to 124,001). Before the third quarter of 1993, quarterly nonfatal and fatal firearm-related injury rates in the total US population and quarterly nonfatal firearm assaultive injury and firearm homicide rates for males aged 15 to 24 years were observed to be on the rise. Since then, these rates have significantly declined.

CONCLUSION

Analysis of national trends indicates that non-fatal and fatal firearm-related injuries are declining in the United States, although the rate of firearm-related deaths remains high, especially among males aged 15 to 24 years, in relation to other leading causes of injury death. An assessment of factors responsible for the decline in firearm-related injuries is needed to design further prevention efforts.

Calcified aldosterone-producing adrenocortical adenoma

We report the first case of benign aldosteronoma of an ordinary size with calcifications. We review the clinical, clinical imaging, histopathological, and laboratory features of aldosterone-producing adrenal adenoma versus carcinoma. We conclude that no single feature is diagnostic, and the full range of data must be considered. Calcifications may not necessarily be a distinguishing point.

A re-evaluation of the hemodynamic consequences of intermittent positive pressure ventilation

The hemodynamic effects of intermittent positive pressure ventilation (IPPV) have generally been considered straightforward, being dominated by the inspiratory reduction in systemic venous return. Paradoxically, there is considerable debate regarding the effects of PEEP. We have studied both right ventricular (RV) and left ventricular (LV) performance during a single IPPV respiratory cycle in dogs with intact circulatory systems or the right heart bypassed in open and closed chest conditions. We have found that the "reverse pulsus paradoxus" during inspiration reflects both transmission of the increased intrathoracic pressure to the thoracic aorta and an increase in LV stroke volume (SV). This inspiratory increase in LVSV has been found to be influenced by, but not dependent on: (a) respiratory variations in RVSV; (b) variations in functional residual capacity or tidal volume altering pulmonary venous return and the degree of physical compression of the heart by the lungs; (c) an inspiratory decrease in RV volume, increasing LV diastolic compliance and, thus, probably improving pulmonary venous return; (d) a decreased transmural aortic diastole pressure reflecting an effective decrease in LV afterload produced by both the general increase in intrathoracic pressure and the direct compression of the heart; and (e) variations in the pulmonary vascular volume as indicated by changes in the transmural LV end-diastolic pressure. An understanding of IPPV during a single respiratory cycle facilitates an appreciation of the steady state hemodynamic effects of IPPV with or without PEEP. Our results imply that measurements made only at end-expiration, ignoring inspiratory events, may have serious limitations. Furthermore, they suggest that IPPV with PEEP should be evaluated as a form of LV assist in LV failure.

High frequency ventilation in dogs with open chests

This study evaluated and compared the physiological responses to high frequency percutaneous transtracheal ventilation in dogs before and after median sternotomy thoracotomy. Standard intermittent positive pressure ventilation (IPPV) was established before and after high frequency rates (100 and 300 breath/min) with the chest closed and then after thoracotomy. Gas exchange as judged by arterial and mixed venous blood gases, and cardiac performance as judged by pulmonary capillary wedge pressure, pulmonary and systemic arterial pressures, vascular resistances, and cardiac index all remained clinically acceptable. Physiologically, ventilation in the open chest condition was adequate but was associated with a slight decrease in PaCO2 and a decrease in PaO2. Peak and mean airway pressures were similar for IPPV and high frequency modes of ventilation.