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Biomedical subjects

Christine B Ambrosone

Publications and source records attributed to Christine B Ambrosone.

At least 19 recordsLinked to original sources
PubMed2007

Predictive factors for late normal tissue complications following radiotherapy for breast cancer.

BACKGROUND AND PURPOSE: Radiotherapy after breast-conserving surgery is commonly applied to reduce recurrence of breast cancer but may cause acute and late side effects. To identify prognostic factors for the development of late toxicity after radiotherapy, we conducted a prospective study of breast cancer patients. PATIENTS AND METHODS: We assessed late complications of radiotherapy and collected information on epidemiologic factors in a cohort of breast cancer patients who had received radiotherapy after breast-conserving surgery. Among 416 patients with complete follow-up data, the association between possible risk factors and development of late complications was evaluated using multivariate logistic regression analysis. RESULTS: After a median follow-up time of 51 months, 131 (31.4%) patients presented with telangiectasia and 28 (6.7%) patients with fibrosis. We observed a strong association between development of telangiectasia and fibrosis (p < 0.01). Increasing age of the patient was a risk factor for both telangiectasia and fibrosis (p-value for trend <0.01 and 0.03, respectively). Patients with acute skin toxicity (odds ratio (OR) 1.8, 95% confidence interval (CI) 1.0-3.1) were at higher risk to develop telangiectasia. Long-term smoking was associated with a significant increase in risk of telangiectasia compared to non-smokers (OR 2.3, 95% CI 1.2-4.6). CONCLUSIONS: Our study revealed several factors other than radiation dose that may predispose to late complications following radiotherapy. Further understanding of differences in response to irradiation may advance individualized treatment and improve cosmetic outcome.

Adult↗
PubMed2007

Lifestyle factors and survival in women with breast cancer.

With increasing longevity and more effective cancer therapies, the population of cancer survivors is increasing. For example, it is estimated that there are over 2 million breast cancer survivors in the United States. Among cancer survivors and their families, there is substantial interest in whether there is anything that they can do beyond conventional therapy to improve their prognosis. Chief among these is interest in diet and use of complementary and alternative therapies. Despite this interest, there is surprisingly little that is known about the effects of these factors on cancer survival. This is in part because of the usual approach to research on diet and breast cancer in human populations. Studies that have had food and nutrition as a main interest have focused almost exclusively on cancer etiology and prevention; there are literally hundreds of such studies. Meanwhile, studies of populations after a breast cancer diagnosis have rarely considered lifestyle factors. Such studies have focused largely on therapeutics, such as effects of different chemotherapy regimens, or prognostic factors, such as the effects of stage of disease, hormone receptor status, or gene expression signatures on prognosis. To the extent that lifestyle factors have been a focus of cancer prognosis studies, they have often been aimed at the question of whether they impact quality of life, and not on whether they influence cancer survival or recurrence. There have been a handful of studies that have had lifestyle factors such as diet and physical activity as a principal focus. In addition to 2 randomized trials, the Women's Intervention Nutrition Study (WINS) and the Women's Healthy Eating and Living Study, there are at least 5 ongoing prospective cohort studies in breast cancer survivors that have diet as a main focus. Although these studies differ in various aspects, they are all aimed at examining whether differences in diet may result in differences in recurrence and mortality rates. One such study, the Pathways Study, is a prospective cohort study that began recruitment of study participants in early 2006. This study is unique in that it is enrolling women as soon after breast cancer diagnosis as is practical, whereas other studies have generally enrolled women after completion of adjuvant therapy or later. This and other studies promise to provide some of the first objective information regarding diet and breast cancer prognosis and serve as models for studies of diet and prognosis of other cancers.

Breast Neoplasms↗
PubMed2006

Polymorphisms in DNA repair genes and therapeutic outcomes of AML patients from SWOG clinical trials.

Repair of damage to DNA resulting from chemotherapy may influence drug toxicity and survival in response to treatment. We evaluated the role of polymorphisms in DNA repair genes APE1, XRCC1, ERCC1, XPD, and XRCC3 in predicting therapeutic outcomes of older adults with acute myeloid leukemia (AML) from 2 Southwest Oncology Group (SWOG) clinical trials. All patients received standard chemotherapy induction regimens. Using logistic and proportional hazards regression models, relationships between genotypes, haplotypes, and toxicities, response to induction therapy, and overall survival were evaluated. Patients with XPD Gln751C/Asp312G ('D') haplotype were more likely to have complete response (OR = 3.06; 95% CI, 1.44-6.70) and less likely to have resistant disease (OR = 0.32; 95%CI, 0.14-0.72) than patients with other haplotypes. ERCC1 polymorphisms were significantly associated with lung (P = .037) and metabolic (P = .041) toxicities, and patients with the XRCC3 241Met variant had reduced risk of liver toxicity (OR = 0.32; 95%CI, 0.11-0.95). Significant associations with other toxicities were also found for variant XPD genotypes/haplotypes. These data from clinical trials of older patients treated for AML indicate that variants in DNA repair pathways may have an impact on both outcomes of patients and toxicities associated with treatments. With validation of results in larger samples, these findings could lead to optimizing individual chemotherapy options.

Adult↗
PubMed2006

Polymorphisms in genes related to oxidative stress (CAT, MnSOD, MPO, and eNOS) and acute toxicities from radiation therapy following lumpectomy for breast cancer.

PURPOSE: Because radiotherapy exerts cytotoxic effects via generation of massive oxidative stress, we hypothesized that catalase, manganese superoxide dismutase, myeloperoxidase (MPO), and endothelial nitric oxide synthase (eNOS) genotypes might result in greater risk of radiotoxicity. EXPERIMENTAL DESIGN: Cases (n = 446) were Caucasian women with breast cancer who received radiotherapy following lumpectomy. Genotypes were determined by matrix-assisted laser desorption/ionization time-of-flight. The development of acute reactions (moist desquamation) associated with genotypes was modeled using the Cox proportional hazards model, accounting for cumulative biologically effective radiation dose. RESULTS: Genotypes associated with higher levels of reactive oxygen species (ROS) were not associated with risk of radiotoxicity. However, relationships between overweight/obesity [body mass index (BMI), >25] and radiotoxicity risk seemed to be modified by eNOS and MPO genotypes associated with higher generation of nitric oxide and ROS, respectively. Women with high BMI (>25) and eNOS GG genotypes were at more than a 6-fold increase in risk (hazard ratio, 6.39; 95% confidence interval, 2.53-16.15) compared with those with BMI <25, and for MPO, those with high BMI (>25) and GG genotypes also had greater risk of radiotoxicity (hazard ratio, 3.61; 95% confidence interval, 1.78-7.35) compared with those with BMI <25. Overweight/obesity was not a strong risk factor among women with other eNOS and MPO genotypes. Exploratory analysis using classification and regression trees indicated that total number of risk alleles contributed, in part, to acute toxicity outcomes among a subgroup of women. CONCLUSIONS: Associations between BMI and radiotoxicity risk may be most apparent among women with genotypes related to higher levels of oxidative stress. Regression trees may be useful in future studies to examine the contributions of multiple factors to individual susceptibility to adverse effects of cancer treatment.

Adult↗
PubMed2006

Breast cancer in African-American women: differences in tumor biology from European-American women.

Disparities exist between African-American and European-American women in the incidence and nature of breast cancer. African-American women are more often diagnosed with breast cancer at an earlier age and with more aggressive disease, characterized by higher grade and negative estrogen and progesterone receptor status. Recent findings reveal specific gene expression patterns associated with the more aggressive breast cancers observed in African-American women. An overview of the current literature about racial differences in breast cancer prompts questions for future research to elucidate causes for the apparent disparities in tumor biology.

Black People↗
PubMed2006

Effects of glutathione S-transferase A1 (GSTA1) genotype and potential modifiers on breast cancer risk.

Glutathione S-transferases (GSTs) are phase II enzymes that are involved in the detoxification of a wide range of carcinogens. The novel GSTA1*A and GSTA1*B genetic polymorphism results in differential expression, with lower transcriptional activation of GSTA1*B (variant) than that of GSTA1*A (common) allele. Considering that cruciferous vegetables induce GSTs, which metabolize tobacco smoke carcinogens, we hypothesized that the variant GSTA1*B genotype may predispose women to breast cancer, particularly among low cruciferous vegetable consumers and among smokers. Thus, we evaluated potential relationships between GSTA1 polymorphisms and breast cancer risk, in relation to vegetable consumption and smoking status in the Long Island Breast Cancer Study Project (1996-1997), a population-based case-control study. Genotyping (1036 cases and 1089 controls) was performed, and putative breast cancer risk factors and usual dietary intakes were assessed. Having GSTA1*A/*B or *B/*B genotypes was not associated with increased breast cancer risk, compared to having the common *A/*A genotype. However, among women in the lowest two tertiles of cruciferous vegetable consumption, *B/*B genotypes were associated with increased risk (OR (95% CI)=1.73 (1.10-2.72) for 0-1 servings/week), compared to women with *A/*A genotypes. Among women with *B/*B genotypes, a significant inverse trend between cruciferous vegetable consumption and breast cancer risk was observed (P for trend=0.05), and higher consumption (4+ servings/week) ameliorated the increased risk associated with the genotype. Current smokers with *B/*B genotypes had a 1.89-fold increase in risk (OR (95% CI)=1.89 (1.09-3.25)), compared with never smokers with *A/*A genotypes. These data indicate that GSTA1 genotypes related to reduced GSTA1 expression are associated with increased breast cancer primarily among women with lower consumption of cruciferous vegetables and among current smokers.

Alleles↗
PubMed2006

Catechol-O-methyltransferase haplotypes and breast cancer among women on Long Island, New York.

The gene encoding catechol-O-methyltransferase (COMT), critical to the inactivation of reactive catechol estrogens, has several single nucleotide polymorphisms (SNPs) that influence enzyme activity. A 3-SNP haplotype (IVS1+255 C>T; Ex4-12 G>A; 3'UTR-521 A>G), which has been shown to reduce COMT expression in the human brain, has been identified. To evaluate the influence of genetic variation of COMT on breast cancer risk, these 3-SNPs were genotyped in 1052 cases and 1098 controls. We estimated the associations between breast cancer and individual SNPs, as well as, multilocus haplotypes. We also examined surrogates of hormone exposure as potential modifiers of the putatively functional Ex4-12 SNP-breast cancer association. Odds ratios (OR) and 95% confidence intervals (CI) were based on age-adjusted unconditional logistic regression models. We found no association between the individual SNPs alone and breast cancer. When examining the association between breast cancer and the 3-SNP haplotypes, we observed a 19% increase in risk associated with each copy of the TGG haplotype (OR=1.19, 95% CI 0.96-1.49), relative to the common TAA haplotype, which was statistically significant when assuming a dominant model (OR=1.32, 95% CI 1.05-1.67, p-value=0.02). In this report of COMT haplotypes and breast cancer, we found some evidence that additional genetic variability beyond the Ex4-12 G>A SNP contributes to risk of breast cancer among a small subgroup of women; however, these results need to be replicated in additional studies.

Adult↗
PubMed2006

Cancer survivorship--genetic susceptibility and second primary cancers: research strategies and recommendations.

Cancer survivors constitute 3.5% of the United States population, but second primary malignancies among this high-risk group now account for 16% of all cancer incidence. Although few data currently exist regarding the molecular mechanisms for second primary cancers and other late outcomes after cancer treatment, the careful measurement and documentation of potentially carcinogenic treatments (chemotherapy and radiotherapy) provide a unique platform for in vivo research on gene-environment interactions in human carcinogenesis. We review research priorities identified during a National Cancer Institute (NCI)-sponsored workshop entitled "Cancer Survivorship--Genetic Susceptibility and Second Primary Cancers." These priorities include 1) development of a national research infrastructure for studies of cancer survivorship; 2) creation of a coordinated system for biospecimen collection; 3) development of new technology, bioinformatics, and biomarkers; 4) design of new epidemiologic methods; and 5) development of evidence-based clinical practice guidelines. Many of the infrastructure resources and design strategies that would facilitate research in this area also provide a foundation for the study of other important nonneoplastic late effects of treatment and psychosocial concerns among cancer survivors. These research areas warrant high priority to promote NCI's goal of eliminating pain and suffering related to cancer.

Antineoplastic Agents↗
PubMed2006

Association between polymorphisms in the DNA repair genes XRCC1 and APE1, and the risk of prostate cancer in white and black Americans.

PURPOSE: XRCC1 and APE1 are enzymes involved in the repair of DNA strand breaks and base damage that arise from various endogenous and exogenous oxidants. We determined whether polymorphisms in XRCC1 and APE1 increase the risk of prostate cancer. MATERIALS AND METHODS: We performed a case-control study in 228 white American men, 124 black American men, and 335 age, sex and race matched controls. Polymorphisms at codon 399 in XRCC1, and at codons 51 and 148 in APE1 were determined using an restriction fragment length polymorphism method. Frequencies were compared between cases and controls. RESULTS: A significantly increased risk of prostate cancer was observed in white men with the XRCC1(399Gln) allele (OR 1.6, 95% CI 1.1 to 2.4). When APE1 and XRCC1 polymorphisms were evaluated together, we found an increased risk of the XRCC1(399Arg/Gln+Gln/Gln)/APE1(51Gln/Gln) (OR 4.0, 95% CI 1.3 to 12.5) and XRCC1(399Arg/Gln+Gln/Gln)/APE1(148Asp/Asp) (OR 2.9, 95% CI 1.4 to 6.1) genotypes in white men. Significant associations were found between combined genotypes and prostate cancer risk with a dose-effect relationship in white men (trend test p = 0.035 and 0.039, respectively). No significant associations were observed between polymorphisms in these genes and prostate cancer risk in black men. CONCLUSIONS: Our results suggest that inherited variability in DNA repair capacity, as reflected by polymorphisms in XRCC1 and APE1, is a risk factor for prostate cancer.

Adult↗
PubMed2006

p53 Mutation analysis in breast tumors by a DNA microarray method.

The p53 gene acts as a regulator of cell growth and DNA repair in normal cells; inactivation of the gene seems to lead to cancer. It is the most commonly mutated gene in human cancers, and a high-throughput sequencing method is needed for cancer etiology studies using large sample sets. In our population-based case-control study of breast cancer, the p53 gene was amplified by PCR for 392 subjects from seven hospitals in Western New York using the Affymetrix GeneChip technology. One hundred thirty-eight (35%) of the breast tumors had p53 mutations, of which 88% were located in exons 5 to 8. New hotspots were identified at codons 179, 195, 196, 213, 217, 249, 254, 278, 281, and 298, and previously reported hotspots were found at codons 175, 248, and 273. Manual sequencing for exons 5 to 9 of the p53 gene was done for 139 tumors to validate the Affymetrix assay. The two methods had 100% concordance for mutations detectable by the Affymetrix assay. We also successfully assayed paraffin-embedded breast and lung tumors from as early as 1958 and employed a nested PCR strategy to improve weak PCR amplification. To have statistical power, the investigation of gene environment interactions and cancer requires a large number of tumor analyses, which are frequently only available from archived tissue from multiple sources. We have shown the utility of the Affymetrix GeneChip method under these challenging conditions and provided new data for the mutational spectra of breast cancer in a population-based study.

Breast Neoplasms↗
PubMed2006

Associations between catalase phenotype and genotype: modification by epidemiologic factors.

Catalase is an endogenous antioxidant enzyme that neutralizes hydrogen peroxide and is induced by oxidative challenge. A -262C --> T polymorphism in the promoter region of the gene (CAT) is associated with risk of several conditions related to oxidative stress. We sought to determine the functional effects of the CAT polymorphism on enzyme activity in erythrocytes and the potential modifying effects of demographic and lifestyle factors on genotype/phenotype relationships, using specimens and data from controls from breast and prostate cancer studies in Arkansas (n = 420). There was a dose-response reduction in catalase activity by genotype, with geometric means of 115.4 units/mg hemoglobin for those with CC genotypes, 82.1 units/mg for those with CT genotypes, and 73.5 units/mg for those with TT genotypes. Associations were only observed among Caucasians (P < 0.0001), with no effects among African Americans (P = 0.91), and were stronger among women than men, although numbers in stratified analyses were small. Differences in catalase activity by genotype were most pronounced among those in the highest tertiles of consumption of fruits and vegetables (-35%, P = 0.003), with weaker relationships among those who were lower consumers (-21.8%, P = 0.16). Among those with CC genotypes, there was no change in activity by consumption, but there were notable decreases in activity by tertiles of consumption for those with at least one T allele. These data indicate that the CAT -262C --> T polymorphism predicts a portion of catalase phenotype, which may be limited to Caucasians. Associations between genotype and phenotype were modified by dietary factors, illustrating the biochemical complexity of studies of genetic polymorphisms and disease risk.

Adult↗
PubMed2006

Deletion polymorphism of UDP-glucuronosyltransferase 2B17 and risk of prostate cancer in African American and Caucasian men.

PURPOSE: UDP-glucuronosyltransferases (UGT) are a family of enzymes that glucuronidate many endogenous chemicals, including androgens. This makes them more hydrophilic, alters biological activity, and facilitates their excretion. A deletion polymorphism in the UGT2B17 gene was recently described that was associated with a reduced rate of glucuronidation in vivo. The purpose of this study was to determine if the deletion polymorphism is associated with susceptibility to prostate cancer. MATERIALS AND METHODS: UGT2B17 expression was determined by reverse transcription-PCR of pathologically normal prostate tissues (n = 5). In a case-control study with 420 patients with incident primary prostate cancer (127 African Americans and 293 Caucasians) and 487 controls (120 African Americans and 367 Caucasians), the frequency of UGT2B17 deletion polymorphism in genomic DNA was compared between cases and controls with PCR analysis. RESULTS: UGT2B17 mRNA was detected only in individuals with at least one UGT2B17 allele. The frequency of the null genotype was present in 0.11 and 0.12 of Caucasian and African American controls, respectively. When all subjects were considered, a significant association was found between the UGT2B17 deletion polymorphism and prostate cancer risk [odds ratio (OR), 1.7; 95% confidence interval (95% CI), 1.2-2.6]. There was an increase in prostate cancer risk among individuals with UGT2B17 deletion polymorphism in Caucasians (OR, 1.9; 95% CI, 1.2-3.0) but not in African Americans (OR, 1.3; 95% CI, 0.6-2.7). CONCLUSIONS: These results suggest that the UGT2B17 enzyme may play a role in the metabolism of androgens in prostate tissue and that the UGT2B17 deletion polymorphism is associated with prostate cancer risk.

Adult↗
PubMed2006

Establishing a cancer center data bank and biorepository for multidisciplinary research.

The establishment of a biorepository with linkage to clinical and epidemiologic data will provide an invaluable resource for cancer research, including studies of cancer etiology, progression, and prognosis, as well as development of biomarkers for early detection. Developing an infrastructure for a biorepository linked to clinical, pathologic, and epidemiologic data requires significant efforts in strategic planning for efficient means to ascertain, identify, and consent participants, as well as guidelines for blood collection, processing, and storage while maintaining participant privacy rights. In this report, we present an approach to developing a Data Bank and Biorepository at our own institution, with discussion of elements to be considered when establishing such a bank.

Biological Specimen Banks↗
PubMed2006

Genetic predictors of acute toxicities related to radiation therapy following lumpectomy for breast cancer: a case-series study.

INTRODUCTION: The cytotoxic effects of radiation therapy are mediated primarily through increased formation of hydroxyl radicals and reactive oxygen species, which can damage cells, proteins and DNA; the glutathione S-transferases (GSTs) function to protect against oxidative stress. We hypothesized that polymorphisms encoding reduced or absent activity in the GSTs might result in greater risk for radiation-associated toxicity. METHODS: Women receiving therapy in radiation units in Germany following lumpectomy for breast cancer (1998-2001) provided a blood sample and completed an epidemiological questionnaire (n = 446). Genotypes were determined using Sequonom MALDI-TOF (GSTA1, GSTP1) and Masscode (GSTM1, GSTT1). Biologically effective radiotherapy dose (BED) was calculated, accounting for differences in fractionation and overall treatment time. Side effects considered were grade 2c and above, as classified using the modified Common Toxicity Criteria. Predictors of toxicity were modelled using Cox regression models in relation to BED, with adjustment for treating clinic, photon field, beam energy and boost method, and potential confounding variables. RESULTS: Low activity GSTP1 genotypes were associated with a greater than twofold increase in risk for acute skin toxicities (adjusted hazard ratio 2.28, 95% confidence interval 1.04-4.99). No associations were noted for the other GST genotypes. CONCLUSION: These data indicate that GSTP1 plays an important role in protecting normal cells from damage associated with radiation therapy. Studies examining the effects of GSTP1 polymorphisms on toxicity, recurrence and survival will further inform individualized therapeutics based on genotypes.

Adult↗
PubMed2006

Association between manganese superoxide dismutase promoter gene polymorphism and breast cancer survival.

BACKGROUND: Manganese superoxide dismutase (MnSOD) plays a critical role in the detoxification of mitochondrial reactive oxygen species, constituting a major cellular defense mechanism against agents that induce oxidative stress. A genetic polymorphism in the mitochondrial targeting sequence of this gene has been associated with increased cancer risk and survival in breast cancer. This base pair transition (-9 T > C) leads to a valine to alanine amino acid change in the mitochondrial targeting sequence. A polymorphism has also been identified in the proximal region of the promoter (-102 C>T) that alters the recognition sequence of the AP-2 transcription factor, leading to a reduction in transcriptional activity. The aim of our study was to investigate possible associations of the -102 C>T polymorphism with overall and relapse-free breast cancer survival in a hospital-based case-only study. MATERIALS AND METHODS: The relationship between the MnSOD -102 C>T polymorphism and survival was examined in a cohort of 291 women who received chemotherapy and/or radiotherapy for incident breast cancer. The MnSOD -102 C>T genotype was determined using a TaqMan allele discrimination assay. Patient survival was evaluated according to the MnSOD genotype using Kaplan-Meier survival functions. Hazard ratios were calculated from adjusted Cox proportional hazards modeling. All statistical tests were two-sided. RESULTS: In an evaluation of all women, there was a borderline significant reduction in recurrence-free survival with either one or both variant alleles (CT + TT) when compared with patients with wild-type alleles (CC) (odds ratio, 0.65; 95% confidence interval, 0.42-1.01). When the analysis was restricted to patients receiving radiation therapy, there was a significant reduction in relapse-free survival in women who were heterozygous for the MnSOD -102 genotype (relative risk, 0.40; 95% confidence interval, 0.18-0.86). Similarly, when the homozygous and heterozygous variant genotypes were combined, there remained a significant reduction in relapse-free survival in this group (hazard ratio, 0.42; 95% confidence interval, 0.20-0.87). CONCLUSION: The MnSOD -102 variant allele appears to be associated with an improved recurrence-free survival in all patients, and more dramatically in subjects who received adjuvant radiation therapy.

Breast Neoplasms↗