Abcc10 status affects mammary tumour growth, metastasis, and docetaxel treatment response

Background:

Resistance to chemotherapeutic agents is a major obstacle to cancer treatment. A group of ABC efflux pumps, the Multidrug Resistance Proteins, is a source of resistance. Herein, we investigated the role of ABCC10 in mammary tumours, given the important role we have defined for ABCC10 in transporting taxanes, and the recognition that some ABCC proteins have roles in tumour growth.

Methods:

ABCC10 expression was correlated to human breast cancer subtype using breast tissue microarrays. Real-time quantitative PCR and western blot analysis were used to examine ABCC10 expression in human breast cancer lines. Abcc10^−/− mice were crossed to MMTV-PyVmT mice to produce Abcc10^−/−vs Abcc10^+/+ mammary tumours and derivative cell lines. We used allograft and cellular assays to perform baseline and drug sensitization analysis of tumours and cell lines.

Results:

Clinical sample analyses indicated that ABCC10 was more highly expressed in Her2+ and ER+ than in Her2−, ER−, and triple-negative breast cancer. Unexpectedly, PyVmT; Abcc10^−/− tumours grew more rapidly than PyVmT; Abcc10^+/+ tumours and were associated with significantly reduced apoptosis and metastasis. PyVmT; Abcc10^−/− lines were less migratory than PyVmT; Abcc10^+/+ lines. Finally, we showed increased survival of docetaxel-treated MMTV-PyVmT; Abcc10^−/− mice compared with wild-type mice.

Conclusions:

These data identify roles for Abcc10 in breast cancer pathogenesis and in vivo docetaxel resistance.

Abstract P1-05-03: A requirement for neural precursor cell-expressed developmentally downregulated gene 9 during the initiation of mammary tumorigenesis in MMTV-neu mice

The Neural precursor cell-Expressed Developmentally Downregulated gene 9 (NEDD9; also HEF1, CAS-L) scaffolding protein regulates many signaling pathways associated with mitosis, survival, migration, and ciliary integrity. Within the last few years, elevated NEDD9 expression has been implicated in progression and metastasis of several types of cancer, including those of the lung, skin, and brain. We have investigated the consequences of introducing a Nedd9 genotype into the MMTV-neu mouse mammary tumor model, which in many respects recapitulates features of human HER2+ breast cancer. 80% of wild-type MMTV-Neu; Nedd9+/+ animals developed tumors with an average latency of 339 days, but only 18% of MMTV-Neu;Nedd9−/− animals developed tumors with an average latency of 416 days. This highly significant difference indicates that the Nedd9−/− genotype significantly prevents neu-dependent mammary tumor formation.

HER2-positive human breast tumors and MMTV-neu-induced tumors originate from mammary luminal epithelial progenitor cells. We evaluated mammary progenitor cell populations from non-tumor bearing MMTV-neu;Nedd9−/− versus MMTV-neu;Nedd9+/+ 4-month old mice (2 months prior to appearance of tumors). Flow cytometry analysis indicated a significantly reduced CD24high;CD49flow luminal progenitor subpopulation in MMTV-neu;Nedd9−/− and Nedd9−/− mammary glands, that could be contributed to the tumorigenesis resistance in the MMTV-neu;Nedd9−/− model. The MMTV-neu;Nedd9−/−genotype negatively affected the Matrigel mammosphere colony-forming potential of luminal progenitor cells compared to MMTV-neu; Nedd9+/+cells, causing formation of fewer colonies with aberrant size and morphology. Quantification of mitotic division planes of MMTV-neu;Nedd9−/− mammospheres revealed no contribution to the observed defects. However, MMTV-neu;Nedd9−/− mammospheres had defective expression of signaling proteins governing cell attachment, with reduced levels of FAK and more cytoplasmic localization of SRC.

The results reported above, together with other data, support three main conclusions. First, they revealed a very substantial requirement for Nedd9 during early stages of HER2/neu-dependent tumor formation. Second, these results are the first to demonstrate a role for Nedd9 in supporting the abundance and colony-forming potential of mammary luminal progenitor cells. Third, they indicate that the defects in mammosphere growth likely involve perturbation of crucial cellular attachment signaling pathways involving FAK and SRC. In sum, these data provide a strong justification for future analysis of NEDD9 in the defective signaling of transformed mammary epithelial progenitor cell populations that initiate human breast cancer.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P1-05-03.

Abstract P6-08-01: Perceptions of breast cancer risk, psychological adjustment and behaviors in adolescent girls at high-risk and population-risk for breast cancer

BACKGROUND: Preliminary evidence suggests that many girls from breast cancer (BC) families are aware of their increased risk for BC. How this awareness impacts their psychosocial adjustment and health behaviors remains unknown.

METHODS: 11–19 YO girls at high-risk (HR) or population-risk (PR) for BC completed self-administered quantitative surveys informed by the Self-Regulation Theory of Health Behavior. Girls with a first or second-degree relative with BC were classified as HR. For hypothesis testing, we used simple linear and logistic regressions. To account for correlation of responses within families, we used robust (cluster-corrected) standard errors or Generalized Estimating Equations.

RESULTS: 47 PR and 89 HR girls have completed surveys. Age did not differ between groups (Mage = 15.6; SD=2.4). 30% of HR girls have a mother with BC. 67% of HR girls vs. 30% of PR girls reported self-perceived risk for adult BC to be “higher than other girls my age,” (p = <0.01, Table 1).

Genetic counselor opinions of, and experiences with telephone communication of BRCA1/2 test results

BRCA1/2 test disclosure has, historically, been conducted in-person by genetics professionals. Given increasing demand for, and access to, genetic testing, interest in telephone and Internet genetic services, including disclosure of test results, has increased. Semi-structured interviews with genetic counselors were conducted to determine interest in, and experiences with telephone disclosure of BRCA1/2 test results. Descriptive data are summarized with response proportions. One hundred and ninety-four genetic counselors completed self-administered surveys via the web. Although 98% had provided BRCA1/2 results by telephone, 77% had never provided pre-test counseling by telephone. Genetic counselors reported perceived advantages and disadvantages to telephone disclosure. Thirty-two percent of participants described experiences that made them question this practice. Genetic counselors more frequently reported discomfort with telephone disclosure of a positive result or variant of uncertain significance (p < 0.01) than other results. Overall, 73% of participants reported interest in telephone disclosure. Many genetic counselors have provided telephone disclosure, however, most, infrequently. Genetic counselors identify potential advantages and disadvantages to telephone disclosure, and recognize the potential for testing and patient factors to impact patient outcomes. Further research evaluating the impact of testing and patient factors on cognitive, affective, social and behavioral outcomes of alternative models of communicating genetic information is warranted.

Should Minors Be Offered BRCA1/2 Testing for Hereditary Breast Cancer? Opinions of Parents Who Have Undergone BRCA1/2 Testing

Background: Professional societies recommend against the genetic testing of minors for hereditary cancer syndromes that present in adulthood. Yet, many adolescent specialists indicate that they would consider BRCA1/2 testing of minor children. We conducted interviews with parents who have had BRCA1/2 testing, to evaluate their opinions regarding the genetic testing of minors for BRCA1/2. Methods: 244 parents, including 67 BRCA1/2 mutation carriers (MCs), 140 parents with uninformative negative results (UN), 14 with true negative results (TN) & 23 with a variant of uncertain significance (VUS), from two cancer risk assessment programs completed semi-structured interviews. We used multiple logistic regressions to evaluate the associations among biomedical factors, demographic factors and support of testing minors. Wald tests and likelihood ratio tests were used to assess statistical significance for binary covariates and nominal covariates. Results: 38% of parents supported testing minors for BRCA1/2 in response to a dichotomous (Y/N) question. Support was greatest among parents with TN (64%) and UN (40%) results and lower among MCs (31%) and parents with a VUS (26%). In a multivariable analysis, support was greatest among parents who tested negative (p=0.02), were of minority race (p=0.06) and among fathers (&lt;0.01). Responses to open-ended questions suggest that 27% of parents unconditionally support testing of minors, and 25% support testing only in certain situations. Psychological risks, a lack of medical necessity and the insufficient maturity of minors, were frequent concerns of those opposed. The potential to positively impact minors' health behaviors was the most reported reason for supporting testing. Conclusions: Up to 52% of parents who have undergone BRCA1/2 testing support pediatric testing for BRCA1/2. Given willingness among general and pediatric practitioners and interest among parents, further research is necessary to formally evaluate the risks and benefits of providing genetic testing to minors for adult-onset hereditary cancer syndromes in order to inform clinical practice and public policy that will ensure optimal psychosocial and medical outcomes for all members of families at risk for hereditary cancer.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 4071.

Understanding how out-of-pocket expenses, treatment value, and patient characteristics influence treatment choices

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Background: Cost-sharing is a method to control “over-use” of healthcare services but may have the unintended consequence of reducing utilization of necessary services among vulnerable patients (pts). It is not known if cost influences pts’ choices of cancer treatments. Methods: A survey was administered to a convenience sample of pts on surveillance for localized cancer. Domains included demographic questions as well as clinical scenarios to elicit the maximum co-payment pts would be willing to pay for hypothetical cancer treatments. Scenario A described adjuvant therapy; questions varied reductions in recurrence rates from 5–20%. Scenario B described palliative therapy; questions varied 2-year survival between 19–34%. Scenario C described palliative therapy; questions varied improvement in median life expectancy from 11–20 months. GEE fit multiple logistic regressions examined pts’ characteristics associated with willingness to pay (WTP). Pts chose from 9 co-payment levels (highest: >$7,000/6 months for Scenario A; >$1,000/3 weeks for Scenarios B-C), which were dichotomized (highest 5 vs lowest 4 levels). Results: 60 pts completed the survey. Demographics: Female (78%); < 65 (83%), Caucasian (97%), college degree (58%). 13% reported making financial sacrifices to pay for treatment. Overall, pts showed a greater WTP for more effective treatments (p<0.05 for all 3 scenarios). In Scenario B, pts who were currently working demonstrated a greater WTP (OR 12.6 95% CI 2.0 -80.4) when controlling for dichotomized efficacy. In Scenario C, pts with a college degree showed greater WTP (OR 5.0, 96% CI 1.2–20.9). In addition, pts who reported having to make previous financial sacrifices for care showed lower WTP (OR 0.2 95%CI 0.04–0.6). Conclusions: Pts may assign a higher value to treatments of greater efficacy. Even among this relatively young, affluent and educated group, demographic variables were associated with WTP. Larger studies in more diverse populations are required to further elucidate how cost may influence pts'treatment choices and contribute to health disparities. These findings may inform health policy by suggesting benefit plans that use cost sharing to optimize use of limited health care resources without compromising access to needed care.

[Table: see text]

Parent perceptions of offspring responses to parental communication of BRCA1/2 test results

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Background: Many BRCA1/2 mutation carriers report sharing their genetic test results with their minor children. The impact of this communication on offspring remains unknown. Methods: 163 parents who had BRCA1/2 testing completed qualitative interviews regarding their experiences with communication of their genetic test results to offspring. Descriptive responses were coded and response proportions utilized to summarize results. We used multiple regressions fit by GEE to test associations with disclosure. We controlled for parent mutation status in each regression. Results: 163 parents (52 BRCA1/2 mutation carriers) reported on 323 offspring 5 to 25 years old at the time of parent genetic testing. 107 (66%) parents reported disclosing to at least one offspring. Child age (p < 0.001) and parent cancer history (p = 0.004) were positively associated with disclosure. Parents without a BRCA1/2 mutation were more likely to communicate test results than parents with a mutation (p = 0.007). Among parents who disclosed, few (14%) reported they perceived their offspring to have had an initial negative affective or behavioral response. Others (13%) reported offspring concern for self and family. Reports of initial negative responses and concern were more frequent among parents with a mutation or a variant of uncertain significance. Many parents reported that the communication had no significant impact (39%) or a positive impact (36%) on their offspring. Conclusions: Many parents report sharing BRCA1/2 test results with their offspring. Parent self-reports suggest that they do not perceive most offspring to experience adverse reactions to this communication. Self-reports suggest that offspring learning of a BRCA1/2 mutation or a variant of uncertain significance may be more susceptible to initial negative reactions. Further research is necessary to explore psychosocial and behavioral responses to learning of hereditary risk during childhood and adolescence, and to inform the development of interventions to optimize adaptive response.

No significant financial relationships to disclose.

Phase II trial of docetaxel-irinotecan combination in advanced esophageal cancer

BACKGROUND

Preclinical evidence suggests synergy between docetaxel and irinotecan, two drugs active in esophagogastric cancer. We previously demonstrated the safety of docetaxel 35 mg/m2 and irinotecan 50 mg/m2 given on days 1 and 8 of a 21-day schedule.

MATERIALS AND METHODS

Patients who had unresectable/metastatic squamous cell carcinoma or adenocarcinoma of the esophagus, measurable disease, Eastern Cooperative Oncology Group performance status of zero to two, and normal bilirubin were eligible. Tumor assessment was carried out every three cycles.

RESULTS

We enrolled 29 chemotherapy-naive (CN) and 15 chemotherapy-exposed (CE) eligible patients. Principal toxic effects were diarrhea, neutropenia, and hyperglycemia. There were no toxic deaths. There was one early death, from myocardial infarction. Among 26 CN and assessable patients, there were seven (26.9%) with a partial response (PR) and one (3.8%) with a complete response (CR). There were two PRs and one CR among the patients with CE disease. Median time to progression for CN patients was 4.0 months and for CE patients 3.5 months. Median survival for CN eligible patients was 9.0 months and for CE patients 11.4 months.

CONCLUSIONS

Docetaxel-irinotecan combination given on a weekly x 2 of 3 schedule is promising in the treatment of advanced esophageal cancer.

Patterns of prostate cancer treatment by clinical stage and age

OBJECTIVES

This study analyzed prostate cancer treatment rates by age and clinical stage and contrasted these with rates by most accurate stage.

METHODS

We determined surgery and radiation rates by most accurate and clinical stage by using 1996 Surveillance, Epidemiology, and End Results data.

RESULTS

Treatment rates by clinical stage vs best stage differ significantly. For example, surgery rates for stages B, C, and D are 37%, 78%, and 13% by most accurate stage but 33%, 6%, and 1% by clinical stage. Treatment patterns by clinical stage vary substantially by age.

CONCLUSIONS

Treatment patterns should be described by clinical stage rather than most accurate stage, and they vary by age.

Effect of future costs on cost-effectiveness of medical interventions among young adults: the example of intensive therapy for type 1 diabetes mellitus

OBJECTIVES

Recent research based on a lifetime utility maximization model has suggested that cost-effectiveness analyses should account for all future costs, including medical costs for related and unrelated illnesses and nonmedical costs. This work has also shown that analyses that omit future costs are biased to favor interventions among the elderly that extend life over interventions that improve quality of life. However, the effect of including future costs on the cost-effectiveness of interventions among the young has not been studied. This article examines the effect of including future costs on the cost-effectiveness of intensive therapy for type 1 diabetes mellitus among young adults.

METHODS

By modifying a cost-effectiveness model based on the Diabetes Control and Complications Trial to include future costs, the effect of including future costs on the cost-effectiveness of intensive therapy for type 1 diabetes mellitus among young adults was examined. Future costs added to the model included future costs for medical expenditures for illnesses unrelated to diabetes and future nonmedical expenditures net of earnings.

RESULTS

Intensive therapy among young adults led to approximately equal increases in the expected number of years lived before age 65, when people generally produce more than they consume, and after age 65, when the opposite tends to hold. Because the discounted value of savings due to lower mortality before age 65 exceeded the discounted value of later increases in costs due to lower mortality after age 65, accounting for future costs decreased the cost-effectiveness ratio from $22,576 to $9,626 per quality-adjusted life-year.

CONCLUSIONS

The inclusion of future costs can significantly improve the cost-effectiveness of interventions that decrease mortality among young adults. The common practice of excluding future costs may bias cost-effectiveness analyses against such interventions.

How patients with diabetes perceive their risk for major complications

CONTEXT

To educate patients with diabetes about their illness and to motivate these patients to pursue intensive treatment, physicians often inform them about their risk for serious complications. However, little is known about patient perceptions of these risks.

OBJECTIVE

To compare patient perceptions of risk for major complications of diabetes with actual risk for these complications.

DESIGN

Structured interviews were done to obtain the patient's estimate of their risk for complications. To generate estimates of actual risk for each patient, we used a simulation model based on the Diabetes Control and Complications Trial (DCCT).

SETTING

Four university-affiliated diabetes clinics in the midwestern United States.

PATIENTS

139 patients with type 1 diabetes mellitus.

MAIN OUTCOME MEASURES

Probability of blindness, end-stage renal disease (ESRD), and lower-leg amputation over 20 years.

RESULTS

Participants were young (mean age, 30 years) and reported having had diabetes for an average of 15 years. Seventy-nine percent reported their current diabetic therapy to be "intensive." Ninety-eight percent had completed high school, and 51% were college graduates. The patients' estimates of their risks far exceeded the DCCT estimates for all three complications. The mean patient estimate of the risk for blindness was 31.6% (DCCT estimate, 17.0%), of the risk for ESRD was 33.7% (DCCT estimate, 8.7%), and of the risk for amputation was 25.1% (DCCT estimate, 1.9%). Similarly, patients overestimated the benefit of intensive therapy. They estimated, on average, that intensive therapy would result in a 17.0% absolute risk reduction for blindness (DCCT estimate, 12.2%), an 18.1% risk reduction for ESRD (DCCT estimate, 7.0%), and a 14.2% risk reduction for amputation (DCCT estimate, 1.2%).

CONCLUSION

Patients with diabetes overestimated their risk for major complications and the benefits of intensive treatment.

Parental availability for the care of sick children

OBJECTIVE

Parents have always played a critical role in the care of sick children. Although parents' roles remain crucial to children's health, parental availability has declined during the past half century. The percentage of women with preschool children who work has risen almost fivefold in 45 years from 12% in 1947 to 58% in 1992. The percentage of women in the paid work force with school-aged children has almost tripled in the same period, from 27.3% to 75.9%. Research has examined the effects of a variety of parental work conditions on children. However, past research has not examined how working conditions affect the ability of parents to care for their sick children. In this article, we examine how often the children of working parents get sick and whether parents receive enough paid leave to care for their sick children.

METHODOLOGY

This analysis makes use of two national surveys, which provide complementary information regarding the care of sick children. The National Longitudinal Survey of Youth is a longitudinal survey of a nationally representative probability sample of 12,686 men and women; the National Medical Expenditure Survey is a panel survey of 34,459 people. First, we estimated the family illness burden. Second, we looked in detail at the number of days of sick leave mothers had. Third, we examined whether mothers who had sick leave had it consistently during a 5-year period. Finally, we conducted a logistic regression to determine what factors were significant predictors of both lacking sick leave.

RESULTS

More than one in three families faced a family illness burden of 2 weeks or more each year. Yet, 28% of mothers had sick leave none of the time they were employed between 1985 and 1990. Employed mothers of children with chronic conditions had less sick leave than other employed mothers. Thirty-six percent of mothers whose children had chronic conditions had sick leave none of the time they were employed. Although 20% of working parents who did not live in poverty lacked sick leave, 38% of parents who did live in poverty lacked sick leave. The problem is also more marked for nonwhite parents. Although 23% of working white parents lacked paid sick leave, 31% of nonwhite parents lacked sick leave. One in six families that lacked sick leave had to cover for more than 4 weeks of family illness during the year.

CONCLUSION

In 1993, the US Congress passed the Family and Medical Leave Act (FMLA). However, by limiting the medical leave to the care of major illnesses, primarily those requiring hospitalization, the FMLA does not address the majority of children's sick care needs. For the common childhood illnesses that are not covered by the FMLA, employed parents often must rely on their sick leave if they are to care for their sick children themselves. Yet, we found that many employed parents lack sick leave. This is particularly true of parents of children with chronic conditions and poor and minority families.