Reply to Schade G. Comment on Hess et al. "Assessing Agreement in Exposure Classifications between Proximity-Based Metrics and Air Monitoring Data in Epidemiology Studies of Unconventional Resource Development."

We appreciate the comments by Dr [...].

Response to Buonocore et al. Comments on Wendt Hess et al. "Assessing Agreement in Exposure Classification between Proximity-Based Metrics and Air Monitoring Data in Epidemiology Studies of Unconventional Resource Development." Int. J. Environ. Res. Public Health 2019, 16, 3055.

We appreciate the comments by Buonocore et al [...].

Assessing Agreement in Exposure Classification between Proximity-Based Metrics and Air Monitoring Data in Epidemiology Studies of Unconventional Resource Development.

Recent studies of unconventional resource development (URD) and adverse health effects have been limited by distance-based exposure surrogates. Our study compared exposure classifications between air pollutant concentrations and "well activity" (WA) metrics, which are distance-based exposure proxies used in Marcellus-area studies to reflect variation in time and space of residential URD activity. We compiled Pennsylvania air monitoring data for benzene, carbon monoxide, nitrogen dioxide, ozone, fine particulates and sulfur dioxide, and combined this with data on nearly 9000 Pennsylvania wells. We replicated WA calculations using geo-coordinates of monitors to represent residences and compared exposure categories from air measurements and WA at the site of each monitor. There was little agreement between the two methods for the pollutants included in the analysis, with most weighted kappa coefficients between -0.1 and 0.1. The exposure categories agreed for about 25% of the observations and assigned inverse categories 16%-29% of the time, depending on the pollutant. Our results indicate that WA measures did not adequately distinguish categories of air pollutant exposures and employing them in epidemiology studies can result in misclassification of exposure. This underscores the need for more robust exposure assessment in future analyses and cautious interpretation of these existing studies.

Cancer stem cell markers are enriched in normal tissue adjacent to triple negative breast cancer and inversely correlated with DNA repair deficiency.

INTRODUCTION: We hypothesized that cells present in normal tissue that bear cancer stem cell markers may represent a cancer cell of origin or a microenvironment primed for tumor development, and that their presence may correlate with the clinically defined subtypes of breast cancer that show increased tumorigenicity and stem cell features. methods: Normal tissues sampled at least 5 cm from primary tumors (normal adjacent tissue) were obtained from 61 chemotherapy-naive patients with breast cancer treated with mastectomy. Samples were stained simultaneously with immunofluorescence for CD44/CD49f/CD133/2 stem cell markers. We assessed the association between CD44+CD49f+CD133/2+ staining in normal adjacent tissue and breast cancer receptor subtype (defined by the expression of the estrogen (ER), progesterone (PR), or human epidermal growth factor-2 (Her2) receptors). We also examined the correlation between CD44+CD49f+CD133/2+ immunofluorescence and each of two previously published gene signatures, one derived from stem-cell enriched tissue and one from BRCA mutated tissue expected to have defective DNA repair. RESULTS: Patients with triple negative breast cancer (ER­/PR­/HER2­) expressed CD44+CD49f+CD133/2+ in 9 of 9 normal adjacent tissue samples compared with 7 of 52 ER+ and/or Her2+ tumors (P < 0.001). Further, expression of CD44+CD49f+CD133/2+ by normal adjacent tissue correlated positively with a stem cell-derived tumorigenic signature (P <0.001) and inversely with a defective DNA-repair signature (P <0.001). CONCLUSION: Normal cells bearing cancer stem cell markers are associated with the triple negative receptor subtype of breast cancer. This study suggests stem cell staining and gene expression signatures from normal breast tissues represent novel tissue-based risk biomarkers for triple negative breast cancer. Validation of these results in additional studies of normal tissue from cancer-free women could lay the foundation for future targeted triple negative breast cancer prevention strategies.

A phase II neoadjuvant trial of anastrozole, fulvestrant, and gefitinib in patients with newly diagnosed estrogen receptor positive breast cancer.

Endocrine therapy in patients with breast cancer can be limited by the problem of resistance. Preclinical studies suggest that complete blockade of the estrogen receptor (ER) combined with inhibition of the epidermal growth factor receptor can overcome endocrine resistance. We tested this hypothesis in a phase II neoadjuvant trial of anastrozole and fulvestrant combined with gefitinib in postmenopausal women with newly diagnosed ER-positive breast cancer. After a baseline tumor core biopsy, patients were randomized to receive anastrozole and fulvestrant or anastrozole, fulvestrant, and gefitinib (AFG) for 3 weeks. After a second biopsy at 3 weeks, all patients received AFG for 4 months and surgery was done if the tumor was operable. The primary endpoint was best clinical response by RECIST criteria and secondary endpoints were toxicity and change in biomarkers. The study closed after 15 patients were enrolled because of slow accrual. Median patient age was 67 years and median clinical tumor size was 7 cm. Four patients had metastatic disease present. Three patients withdrew before response was assessed. In the remaining 12 patients, there were two complete clinical responses (17%), three partial responses (25%), five had stable disease (41%), and two (17%) had progressive disease. Most common adverse events were rash in four patients, diarrhea in four, joint symptoms in three, and abnormal liver function tests in three. There were no grade 4 toxicities and all toxicities were reversible. At 3 weeks, cell proliferation as measured by Ki-67 was significantly reduced in the AFG group (P value = 0.01), with a parallel reduction in the expression of the Cyclin D1 (P value = 0.02). RNA microarray data showed a corresponding decrease in the expression of cell cycle genes. These results suggest that AFG was an effective neoadjuvant therapy and consistently reduced proliferation in ER-positive tumors.

A review of body size and breast cancer risk in Hispanic and African American women.

Obesity is an epidemic in the United States, especially among Hispanics and African Americans. Studies of obesity and breast cancer risk have been conducted primarily in non-Hispanic whites. There have been few studies of the association between body mass index (BMI) or weight gain and the risk of breast cancer in minorities, and the results have been inconsistent. Because most studies are conducted primarily in non-Hispanic whites, the etiology of breast cancer in minorities is not well understood. The authors of the current report reviewed the literature on the association between obesity, weight, and weight gain and breast cancer in minorities using a combination of the Medical Subject Heading (MeSH) terms "obesity," "body mass index," "weight," "weight gain," "Hispanic," and "African American." Only publications in English and with both risk estimates and 95% confidence intervals were considered. Forty-five studies of body size and breast cancer risk in non-Hispanic whites were identified. After an exhaustive search of the literature, only 3 studies of body size and breast cancer were conducted in Hispanic women were identified, and only 8 such studies in African American women were identified. The results were inconsistent in both race/ethnicity groups, with studies reporting positive, inverse, and null results. Thus, as obesity rates among Hispanics and African Americans continue to rise, there is an urgent need to identify the roles that both obesity and adult weight gain play in the development of breast cancer in these minorities. Additional studies are needed to provide more understanding of the etiology of this disease and to explain some of the disparities in incidence and mortality.

Identification of novel kinase targets for the treatment of estrogen receptor-negative breast cancer.

PURPOSE: Previous gene expression profiling studies of breast cancer have focused on the entire genome to identify genes differentially expressed between estrogen receptor (ER) alpha-positive and ER-alpha-negative cancers. EXPERIMENTAL DESIGN: Here, we used gene expression microarray profiling to identify a distinct kinase gene expression profile that identifies ER-negative breast tumors and subsets ER-negative breast tumors into four distinct subtypes. RESULTS: Based on the types of kinases expressed in these clusters, we identify a cell cycle regulatory subset, a S6 kinase pathway cluster, an immunomodulatory kinase-expressing cluster, and a mitogen-activated protein kinase pathway cluster. Furthermore, we show that this specific kinase profile is validated using independent sets of human tumors and is also seen in a panel of breast cancer cell lines. Kinase expression knockdown studies show that many of these kinases are essential for the growth of ER-negative, but not ER-positive, breast cancer cell lines. Finally, survival analysis of patients with breast cancer shows that the S6 kinase pathway signature subtype of ER-negative cancers confers an extremely poor prognosis, whereas patients whose tumors express high levels of immunomodulatory kinases have a significantly better prognosis. CONCLUSIONS: This study identifies a list of kinases that are prognostic and may serve as druggable targets for the treatment of ER-negative breast cancer.

Effect of lapatinib on the development of estrogen receptor-negative mammary tumors in mice.

Lapatinib, a selective orally available inhibitor of epidermal growth factor receptor (EGFR) and ErbB2 receptor tyrosine kinases, is a promising agent for the treatment of breast cancer. We examined the effect of lapatinib on the development of mammary tumors in MMTV-erbB2 transgenic mice, which express wild-type ErbB2 under the control of the mouse mammary tumor virus promoter and spontaneously develop estrogen receptor (ER)-negative and ErbB2-positive mammary tumors by 14 months of age. Mice were treated from age 3 months to age 15 months with vehicle (n = 17) or lapatinib (30 or 75 mg/kg body weight; n = 16 mice per group) by oral gavage twice daily (6 d/wk). All statistical tests were two-sided. By 328 days after the start of treatment, all 17 (100%) of the vehicle-treated mice vs five (31%) of the 16 mice treated with high-dose lapatinib developed mammary tumors (P < .001). Among MMTV-erbB2 mice treated for 5 months (n = 20 mice per group), those treated with lapatinib had fewer premalignant lesions and noninvasive cancers in their mammary glands than those treated with vehicle (P = .02). Lapatinib also effectively blocked epidermal growth factor-induced signaling through the EGFR and ErbB2 receptors, suppressed cyclin D1 and epiregulin mRNA expression, and stimulated p27 mRNA expression in human mammary epithelial cells and in mammary epithelial cells from mice treated for 5 months with high-dose lapatinib. Thus, cyclin D1, epiregulin, and p27 may represent useful biomarkers of lapatinib response in patients. These data suggest that lapatinib is a promising agent for the prevention of ER-negative breast cancer.

The rates of chemotherapy-induced amenorrhea in patients treated with adjuvant doxorubicin and cyclophosphamide followed by a taxane.

OBJECTIVE: Adjuvant chemotherapy in premenopausal women with breast cancer may induce amenorrhea, which can affect fertility, choice of hormonal therapy, and increase the risk of late toxicity. The incidence of chemotherapy-induced amenorrhea (CIA) resulting from doxorubicin and cyclophosphamide (AC) followed by a taxane (T) is poorly characterized. METHODS: We retrospectively surveyed women who were premenopausal and less than age 50 at initiation of chemotherapy to determine the rates of CIA in women receiving AC followed by T compared with AC alone. RESULTS: One hundred ninety-one eligible women completed the survey. The rate of CIA in women who received AC followed by T was 64% (95% confidence interval [CI] = 55-72%) compared with 55% (95% CI = 43-66%) in AC alone. As expected, CIA rates were higher in older than younger women (82% vs. 55%, P = 0.004). Multivariate logistic regression analysis revealed that age >40 was associated with a 4.6-fold increased risk of CIA (95% CI = 1.7-12.1, P = 0.002). It also revealed that receiving T after AC was associated with an odds ratio of 1.9 for CIA as compared with receiving AC alone (95% CI = 1.0-3.5, P = 0.05). Despite > or =6 months of amenorrhea, many women < or =40 resumed menses (40%). CIA was more likely to be irreversible in those >40. The addition of taxanes did not alter the rate of reversibility for the group as a whole (P = 0.36). CONCLUSIONS: Older age and the addition of taxane to AC increased the risk of CIA and the amenorrhea was more likely to be irreversible for women >40. Women < or =40 often resume menstruation even after 6 months of amenorrhea, and the addition of T does not play a role. Subsequent resumption of menstrual function must be considered when initiating appropriate hormonal therapy.

Primary breast cancer phenotypes associated with propensity for central nervous system metastases.

BACKGROUND: There is anecdotal evidence that the incidence of central nervous system (CNS) metastases in breast cancer patients is increasing. It is unclear whether specific tumor biological properties or the use of systemic therapies influence this risk. METHODS: Using a database of 10,782 patients, 2685 patients were identified who experienced recurrence distantly. Clinical and biological features were analyzed in 2 ways: (1) patients who ever had versus those who never had CNS metastases, and (2) CNS metastases as the first site of recurrence versus those who had other sites. Correlations of survival after CNS metastasis with clinical and biologic features were also analyzed. RESULTS: In the ever versus never analysis, CNS metastases were significantly associated with younger age, premenopausal status, infiltrating ductal carcinoma histology (IDC), estrogen receptor (ER) and progesterone receptor (PR) negativity, low Bcl-2, high S-phase, aneuploidy, and altered p53. Tumor size, lymph node status, and use of adjuvant systemic therapy played little role. HER-2 overexpression was not associated with an increased risk in these patients (none of whom were treated with trastuzumab) (P = .91). However, epidermal growth factor receptor (EGFR) overexpression was associated with increased risk (P = .02). A multivariate analysis revealed ER negativity (odds ratio [OR] 2.8, P < .001), IDC histology (OR 2.5, P = .02), and young age (P < .001) as independent factors for CNS metastases. The clinical and biologic profiles of primary tumors with CNS metastases at first recurrence did not differ from those with CNS metastases after recurrence to other sites, except for HER-2 status. HER-2-positive tumors were not more likely to undergo recurrence initially in the CNS (P =.04). The median survival after CNS metastases was 5.5 months and HER-2-positive patients had a shorter survival. CONCLUSIONS: Younger patients with hormone receptor-negative, highly proliferative, genomically unstable, and p53-altered tumors were at increased relative risk for CNS metastases. HER-2 expression and adjuvant systemic therapies did not increase this risk.

The adherence to practice guidelines in the assessment of bone health in women with chemotherapy-induced menopause.

Premenopausal women are diagnosed with 25% of all invasive breast cancers;adjuvant chemotherapy given to many of this population may induce menopause and increase the risk of osteoporosis development. Guidelines issued by the American Society of Clinical Oncology recommend regular assessment of bone health in such women. To assess appropriate attention to bone health, we performed a retrospective, cross-sectional survey of young women at high risk of osteoporosis secondary to chemotherapy-induced premature menopause. In all, 102 women with chemotherapy-induced menopause, 75% of whom were 40 years of age or younger, were asked whether they underwent screening and preventive measures for osteoporosis. Only 56% had discussed bone health with their healthcare providers; age at diagnosis, race, and use of tamoxifen were not linked to the likelihood of such discussions. Regular exercise was recommended to 73% of the women, calcium supplementation to 56%, and bone mineral density (BMD) testing to 40%. Approximately one half of the women regularly exercised and took a calcium supplement; however, over 37% of those using a supplement took less calcium than that recommended to prevent osteoporosis. Further, 32% reported having had BMD testing;women 40 years of age or younger were less likely to have had such tests (27%) than were older women (48%;P = 0.05). More emphasis must be given to educating breast cancer survivors with chemotherapy-induced menopause about bone health and its maintenance. Approved therapies to prevent osteoporosis probably are underused in this population.