Abstract 753: Associations of inflammatory bowel disease and subsequent cancers in the United States elderly population

Introduction: The risk for cancer may be elevated in patients with inflammatory bowel disease (IBD) due to chronic inflammation caused by IBD and/or immunosuppressive treatments. A comprehensive investigation of cancer as a complication of IBD in elderly patients is needed, as this population has a high background risk of cancer and are underrepresented in IBD studies.

Methods: We performed a case-control study using Surveillance Epidemiology and End Results-Medicare linked data. Cancer cases (N=1,986,735) included all patients aged 66-99 with a first invasive neoplasm diagnosed in 1992-2015. Cancer-free controls (N=200,000) were randomly selected from Medicare and matched by sex, age, and selection year. Medicare claims containing ulcerative colitis (UC) or Crohn's disease (CD) diagnosis codes occurring at least one year prior to selection were used to identify IBD patients. We estimated odds ratios (OR) and 95% confidence intervals (CI) with logistic regression, adjusting for the matching factors, race, and the average number of physician visits per year. A Bonferroni-corrected threshold of significance was defined as p < 0.0003 for 156 tests. Colorectal cancer analyses were further adjusted for the average number of colorectal cancer screens per year occurring at least one year before selection.

Results: IBD, CD, and UC were present in 0.80%, 0.33%, and 0.53% of cancer cases and in 0.76%, 0.30%, and 0.52% of controls, respectively. Out of 52 cancers examined, IBD was significantly associated with cancers of the small intestine (OR=2.53; 95% CI=2.14-2.99), intrahepatic (1.93; 1.48-2.52) and extrahepatic bile ducts (1.73; 1.37-2.19), rectum (1.67; 1.43-1.94), colon (1.20; 1.10-1.31), and lung (1.14; 1.07-1.23). For hematological malignancies, IBD was significantly associated with myelodysplastic syndrome (MDS) (OR=1.45; 95% CI=1.28-1.65) and diffuse large B-cell lymphoma (DLBCL) (1.28; 1.13-1.46). An inverse association was observed for IBD and cancer of the uterus (0.72; 0.62-0.83). CD was associated with cancers of the small intestine (OR= 4.21; 95% CI= 3.40-5.22), myelodysplastic syndrome (1.74; 1.44-2.11), rectum (1.60; 1.1.26-2.03), and lung (1.29; 1.16-1.43) and. UC was associated with cancers of the gastrointestinal system: intrahepatic bile ducts (1.94; 1.41-2.67), rectum (1.88; 1.57-2.25), and colon (1.38; 1.25-1.53).

Conclusions: Our large population-based analysis evaluating a comprehensive range of cancers found IBD significantly associated with increased risk for cancers of the small intestine, biliary tract, colorectum, and lung. IBD was also associated with DLBCL and MDS. Positive associations with IBD and cancers of the gastrointestinal system may reflect complications of chronic inflammation, while associations with DLBCL and MDS may reflect the effect of immunosuppressive medications.

Citation Format: Jeanny Wang, Monica D'Arcy, Eric Engels, Minkyo Song. Associations of inflammatory bowel disease and subsequent cancers in the United States elderly population [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 753.

Abstract 1056: Elevated incidence of rare cancers among solid organ transplant recipients (SOTRs) in the United States

Background: SOTRs, like people with AIDS (PWA), have elevated rates of virus-related cancers. This is due to immunosuppression caused by anti-rejection medications. Cancer classification based only on organ site may mask rare cancer subtypes with distinct etiology that are elevated in SOTRs.

Methods: We used data from a linkage of the US SOTR registry with 17 population-based cancer registries. We categorized first cancers in SOTRs using a classification based on site and histology (Gatta, Eur J Cancer 2011). Standardized incidence ratios (SIRs) compared incidence in SOTRs to the general population.

Results: In a cohort of 262,455 SOTRs, we evaluated 694 cancer types, of which 33 had significantly elevated SIRs (Bonferroni p<7.2E-05, Table). All 33 are rare and some have known viral etiology: Merkel cell carcinoma (SIR 24.7), leiomyosarcoma (26.5), and squamous cell carcinoma (SCC) of the anus (range 6.1-18.8), vulva/vagina (6.8), and penis (3.5). Other cancers with high SIRs include SCC of the lip (SIR 18.3-19.8), salivary gland (9.3), and conjunctiva (13.8); sebaceous adenocarcinoma (34.3); malignant fibrous histiocytoma (15.4); and subtypes of bladder and kidney cancers (10.3-13.3). Some of these cancers are also elevated in PWA to a lesser extent (Shiels, Cancer 2012).

Table:Standardized incidence ratios for cancers that occur at increased incidence among solid organ transplant recipientsCancer typeCasesSIR95% CIOral cavity/pharynxLip, SCC w/variants of lip, NOS2919.7913.2628.43Lip, SCC w/variants of lip, SCC16318.3015.6021.33Salivary gland, epithelial tumors, mucoepidermoid carcinoma184.322.566.82Salivary gland, epithelial tumors, SCC279.256.0913.45Oropharynx, SCC w/variants, SCC1612.231.902.60Digestive systemColon/rectum, adenocarcinoma, signet ring cell carcinoma314.453.026.31Anal canal, SCC, NOS1176.105.057.32Anal canal, SCC, verrucous carcinoma518.766.0943.78Liver and IBD, cholangiocarcinoma of IBD332.631.813.69Respiratory systemNasal cavity and sinuses, SCC, SCC214.472.766.83Lung, adenocarcinoma, mucinous adenocarcinoma213.211.994.91Lung, adenocarcinoma, papillary adenocarcinoma NOS193.552.145.54Soft tissueSarcoma of head and neck, leiomyosarcoma1226.5413.7146.36Sarcoma of head and neck, malignant fibrous histiocytoma815.416.6530.36Non-melanoma skin cancerAdnexal carcinoma NOS159.765.4616.10Adnexal carcinoma, malignant nodular hidradenoma720.398.2042.01Adnexal carcinoma, sclerosing sweat duct carcinoma613.394.9129.14Adnexal carcinoma, sebaceous adenocarcinoma6234.3426.3344.02Merkel cell carcinoma14024.6720.7529.11Soft tissue sarcoma536.464.848.45Breast, male302.351.593.36Genital systemVulva and vagina, SCC w/variants796.765.358.42Penis, SCC w/variants, SCC213.532.185.39Urinary systemBladder, adenocarcinoma NOS156.173.4510.18Bladder, adenocarcinoma, signet ring cell carcinoma610.593.8923.05Bladder, TCC, micropapillary714.185.7029.22Kidney, RCC, clear cell adenocarcinoma NOS3793.783.414.19Kidney, RCC, collecting duct carcinoma610.333.7922.48Kidney, RCC, papillary adenocarcinoma NOS32413.3011.8914.83Kidney, RCC, renal cell adenocarcinoma3963.653.304.03Kidney, RCC, RCC chromophobe type252.901.874.28Eye and adnexa, SCC, squamous carcinoma1613.757.8622.32NET, well differentiated endocrine tumors, carcinoid282.401.593.46Abbreviations: CI confidence interval, IBD intrahepatic bile duct, NET neuroendocrine tumor, NOS not otherwise specified, RCC renal cell carcinoma, SCC squamous cell carcinoma, SIR standardized incidence ratio, TCC transitional cell carcinoma

Conclusion: SOTRs experience elevated rates of selected rare cancers. Further characterization of cancers caused by immunosuppression and viral infections could facilitate prevention and treatment.

Citation Format: Eric Engels, Monica D'Arcy, Ruth Pfeiffer, Meredith Shiels, Lindsay Morton, Amy Kahn, Charles Lynch. Elevated incidence of rare cancers among solid organ transplant recipients (SOTRs) in the United States [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1056.

Allergies and the Subsequent Risk of Cancer among Elderly Adults in the United States

BACKGROUND

Allergic conditions may prevent some cancers by promoting immune surveillance. We examined associations of allergic rhinitis, asthma, and eczema with cancer risk among elderly Americans.

METHODS

We used Surveillance Epidemiology and End Results (SEER)-Medicare linked data to perform a case-control study. Cases were individuals with first cancer diagnosed in SEER registries (1992-2013, ages 66-99; N = 1,744,575). Cancer-free controls (N = 100,000) were randomly selected from Medicare and matched on sex, age, and selection year. Allergic conditions were identified using Medicare claims, and logistic regression was used to estimate adjusted ORs (aOR) with significance gauged with a Bonferroni P cutoff (P < 0.00034).

RESULTS

Allergic rhinitis, asthma, and eczema were present in 8.40%, 3.45%, and 0.78% of controls, respectively. For allergic rhinitis, strong inverse associations (aORs, 0.66-0.79) were observed for cancers of the hypopharynx, esophagus (squamous cell), cervix, tonsil/oropharynx, and vagina/vulva. More modest but significant inverse associations were noted for cancers of the esophagus (adenocarcinoma), stomach, colon, rectosigmoid/rectum, liver, gallbladder, lung, uterus, bladder, and miscellaneous sites. Associations were stronger in analyses requiring a dispensed medication to confirm the presence of allergic rhinitis. Asthma was associated with reduced risk of liver cancer [aOR 0.82; 95% confidence interval (CI), 0.75-0.91], whereas eczema was associated with elevated risk of T-cell lymphoma (aOR, 4.12; 95% CI, 3.43-4.95).

CONCLUSIONS

Inverse associations with allergic rhinitis are present for multiple cancers and require etiologic investigation.

IMPACT

Understanding of mechanisms by which allergic conditions reduce cancer risk may advance cancer prevention and treatment.

DNA defects, epigenetics, and gene expression in cancer-adjacent breast: a study from The Cancer Genome Atlas

Recurrence rates after breast-conserving therapy may depend on genomic characteristics of cancer-adjacent, benign-appearing tissue. Studies have not evaluated recurrence in association with multiple genomic characteristics of cancer-adjacent breast tissue. To estimate the prevalence of DNA defects and RNA expression subtypes in cancer-adjacent, benign-appearing breast tissue at least 2 cm from the tumor margin, cancer-adjacent, pathologically well-characterized, benign-appearing breast tissue specimens from The Cancer Genome Atlas project were analyzed for DNA sequence, copy-number variation, DNA methylation, messenger RNA (mRNA) sequence, and mRNA/microRNA expression. Additional samples were also analyzed by at least one of these genomic data types and associations between genomic characteristics of normal tissue and overall survival were assessed. Approximately 40% of cancer-adjacent, benign-appearing tissues harbored genomic defects in DNA copy number, sequence, methylation, or in RNA sequence, although these defects did not significantly predict 10-year overall survival. Two mRNA/microRNA expression phenotypes were observed, including an active mRNA subtype that was identified in 40% of samples. Controlling for tumor characteristics and the presence of genomic defects, this active subtype was associated with significantly worse 10-year survival among estrogen receptor (ER)-positive cases. This multi-platform analysis of breast cancer-adjacent samples produced genomic findings consistent with current surgical margin guidelines, and provides evidence that extratumoral RNA expression patterns in cancer-adjacent tissue predict overall survival among patients with ER-positive disease.

Abstract B38: Altered p53 status confers molecular subtype-dependent distinct interactions with fibroblasts in breast cancer

Different molecular subtypes of breast cancer have distinct interactions with stromal and immune cells in the cancer microenvironment. However, the role of specific somatic mutations in mediating stromal interactions is not well understood. Conversely, the role of stromal interactions in modulating the biological effects of tumor genetic events is understudied. This project hypothesized that (a) p53 mutations may modulate stromal-epithelial interactions, and (b) stromal-epithelial interactions may potentiate the effects of p53 loss. The p53 gene is mutated in 50% of breast cancers, with 84% of basal-like breast cancers harboring p53 mutations, compared to just 12-32% of luminal breast cancers. The influence of p53 loss on stromal-epithelial interactions across different molecular subtypes may have important implications for tumor progression. To study how gene expression of fibroblast-epithelial cocultures differ in luminal vs. basal-like breast cancers as a function of p53 status, we employed RNAi-mediated p53 knockdown (KD) in a panel of four epithelial cell lines (two basal-like, two luminal). Cocultures were carried out with p53-wildtype or KD cell lines maintained in direct physical contact with fibroblasts for 48 hours before RNA isolation. Results of gene expression analysis show that p53 knockdown significantly altered cell-cell interactions in a subtype-specific manner. Comparing cocultures of p53-wildtype to cocultures of p53 KD basal-like cells, we identified 1600 genes whose expression was significantly altered. Among luminal breast cancer cocultures, the impact of p53 loss on gene expression was far more limited, with no genes identified at the same level of significance. Among basal-likes, p53 loss-associated gene expression occurred in immune response pathways, including IL-8 signaling, IL-15 signaling LXR/RXR activation, TREM1 signaling, B cell receptor signaling. In addition, Wnt/β-catenin Signaling was altered in coculture due to p53 loss. Other recent studies have indicated that p53 may modulate Wnt signaling and EMT via a microRNA-dependent mechanism, and these findings suggest that the p53-Wnt axis is also modulated by stromal-epithelial interactions. These observations strongly suggest that the interactions of epithelial cells with fibroblasts are significantly affected by p53 status. Given the high frequency of basal-like tumors with p53 mutations, it is important to understand how stromal-epithelial interactions potentiate the effects of p53 loss.

Citation Format: Rupninder Sandhu, Monica D'Arcy, Melissa A. Troester. Altered p53 status confers molecular subtype-dependent distinct interactions with fibroblasts in breast cancer. [abstract]. In: Abstracts: AACR Special Conference on Cellular Heterogeneity in the Tumor Microenvironment; 2014 Feb 26-Mar 1; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(1 Suppl):Abstract nr B38. doi:10.1158/1538-7445.CHTME14-B38

Tumor intrinsic subtype is reflected in cancer-adjacent tissue

INTRODUCTION

Overall survival of early-stage breast cancer patients is similar for those who undergo breast-conserving therapy (BCT) and mastectomy; however, 10% to 15% of women undergoing BCT suffer ipsilateral breast tumor recurrence. The risk of recurrence may vary with breast cancer subtype. Understanding the gene expression of the cancer-adjacent tissue and the stromal response to specific tumor subtypes is important for developing clinical strategies to reduce recurrence risk.

METHODS

We utilized two independent datasets to study gene expression data in cancer-adjacent tissue from invasive breast cancer patients. Complementary in vitro cocultures were used to study cell-cell communication between fibroblasts and specific breast cancer subtypes.

RESULTS

Our results suggest that intrinsic tumor subtypes are reflected in histologically normal cancer-adjacent tissue. Gene expression of cancer-adjacent tissues shows that triple-negative (Claudin-low or basal-like) tumors exhibit increased expression of genes involved in inflammation and immune response. Although such changes could reflect distinct immune populations present in the microenvironment, altered immune response gene expression was also observed in cocultures in the absence of immune cell infiltrates, emphasizing that these inflammatory mediators are secreted by breast-specific cells. In addition, although triple-negative breast cancers are associated with upregulated immune response genes, luminal breast cancers are more commonly associated with estrogen-response pathways in adjacent tissues.

CONCLUSIONS

Specific characteristics of breast cancers are reflected in the surrounding histologically normal tissue. This commonality between tumor and cancer-adjacent tissue may underlie second primaries and local recurrences.

IMPACT

Biomarkers derived from cancer-adjacent tissue may be helpful in defining personalized surgical strategies or in predicting recurrence risk.

Role of HGF in epithelial-stromal cell interactions during progression from benign breast disease to ductal carcinoma in situ

Introduction

Basal-like and luminal breast cancers have distinct stromal–epithelial interactions, which play a role in progression to invasive cancer. However, little is known about how stromal–epithelial interactions evolve in benign and pre-invasive lesions.

Methods

To study epithelial–stromal interactions in basal-like breast cancer progression, we cocultured reduction mammoplasty fibroblasts with the isogenic MCF10 series of cell lines (representing benign/normal, atypical hyperplasia, and ductal carcinoma in situ). We used gene expression microarrays to identify pathways induced by coculture in premalignant cells (MCF10DCIS) compared with normal and benign cells (MCF10A and MCF10AT1). Relevant pathways were then evaluated in vivo for associations with basal-like subtype and were targeted in vitro to evaluate effects on morphogenesis.

Results

Our results show that premalignant MCF10DCIS cells express characteristic gene expression patterns of invasive basal-like microenvironments. Furthermore, while hepatocyte growth factor (HGF) secretion is upregulated (relative to normal, MCF10A levels) when fibroblasts are cocultured with either atypical (MCF10AT1) or premalignant (MCF10DCIS) cells, only MCF10DCIS cells upregulated the HGF receptor MET. In three-dimensional cultures, upregulation of HGF/MET in MCF10DCIS cells induced morphological changes suggestive of invasive potential, and these changes were reversed by antibody-based blocking of HGF signaling. These results are relevant to in vivo progression because high expression of a novel MCF10DCIS-derived HGF signature was correlated with the basal-like subtype, with approximately 86% of basal-like cancers highly expressing the HGF signature, and because high expression of HGF signature was associated with poor survival.

Conclusions

Coordinated and complementary changes in HGF/MET expression occur in epithelium and stroma during progression of pre-invasive basal-like lesions. These results suggest that targeting stroma-derived HGF signaling in early carcinogenesis may block progression of basal-like precursor lesions.

Overexpression of miR-146a in basal-like breast cancer cells confers enhanced tumorigenic potential in association with altered p53 status

The tumor suppressor p53 is the most frequently mutated gene in human cancers, mutated in 25-30% of breast cancers. However, mutation rates differ according to breast cancer subtype, being more prevalent in aggressive estrogen receptor-negative tumors and basal-like and HER2-amplified subtypes. This heterogeneity suggests that p53 may function differently across breast cancer subtypes. We used RNAi-mediated p53 knockdown (KD) and antagomir-mediated KD of microRNAs to study how gene expression and cellular response to p53 loss differ in luminal versus basal-like breast cancer. As expected, p53 loss caused downregulation of established p53 targets (e.g. p21 and miR-34 family) and increased proliferation in both luminal and basal-like cell lines. However, some p53-dependent changes were subtype specific, including expression of miR-134, miR-146a and miR-181b. To study the cellular response to miR-146a upregulation in p53-impaired basal-like lines, antagomir KD of miR-146a was performed. KD of miR-146a caused decreased proliferation and increased apoptosis, effectively ablating the effects of p53 loss. Furthermore, we found that miR-146a upregulation decreased NF-κB expression and downregulated the NF-κB-dependent extrinsic apoptotic pathway (including tumor necrosis factor, FADD and TRADD) and antagomir-mediated miR-146a KD restored expression of these components, suggesting a plausible mechanism for miR-146a-dependent cellular responses. These findings are relevant to human basal-like tumor progression in vivo, since miR-146a is highly expressed in p53 mutant basal-like breast cancers. These findings suggest that targeting miR-146a expression may have value for altering the aggressiveness of p53 mutant basal-like tumors.

Dermcidin expression is associated with disease progression and survival among breast cancer patients

Improved diagnostic screening has led to earlier detection of many tumors, but screening may still miss many aggressive tumor types. Proteomic and genomic profiling studies of breast cancer samples have identified tumor markers that may help improve screening for more aggressive, rapidly growing breast cancers. To identify potential blood-based biomarkers for the early detection of breast cancer, we assayed serum samples via matrix-assisted laser desorption ionization-time of flight mass spectrometry from a rat model of mammary carcinogenesis. We found elevated levels of a fragment of the protein dermcidin (DCD) to be associated with early progression of N-methylnitrosourea-induced breast cancer, demonstrating significance at weeks 4 (p = 0.045) and 5 (p = 0.004), a time period during which mammary pathologies rapidly progress from ductal hyperplasia to adenocarcinoma. The highest serum concentrations were observed in rats bearing palpable mammary carcinomas. Increased DCD was also detected with immunoblotting methods in 102 serum samples taken from women just prior to breast cancer diagnosis. To validate these findings in a larger population, we applied a 32-gene in vitro DCD response signature to a dataset of 295 breast tumors and assessed correlation with intrinsic breast cancer subtypes and overall survival. The DCD-derived gene signature was significantly associated with subtype (p < 0.001) and poorer overall survival [HR (95 % CI) = 1.60 (1.01-2.51), p = 0.044]. In conclusion, these results present novel evidence that DCD levels may increase in early carcinogenesis, particularly among more aggressive forms of breast cancer.

Abstract 4196: Over-expression of miR-146a in basal-like breast cancer cells confers enhanced tumorigenic potential in association with altered p53 status

Over-expression of miR-146a in basal-like breast cancer cells confers enhanced tumorigenic potential in association with altered p53 status

p53 is the most frequently mutated gene in human cancers, mutated in 26-30% of breast cancers. However, mutation rates differ according to breast cancer subtype, being more prevalent in aggressive ER negative tumors, basal-like and HER2 amplified subtypes. This heterogeneity suggests that p53 signaling may differ across molecular subtypes of breast cancer. Understanding the inherent differences in p53 pathway in luminal versus basal-like breast cancers is important and could provide a target for development of new treatment strategies. We used RNAi-mediated p53 knockdown in a panel of four cell lines (2 basal-like, two luminal), together with antagomir-mediated knockdown of a p53-regulated microRNA, to study how gene expression and cellular phenotypes of p53 loss differ in luminal vs. basal-like breast cancer. We observed that p53 knockdown significantly altered gene expression and miRNA expression. We identified a common response shared by all cell lines indicating that certain established p53 targets (e.g. p21 and miR-34 family) are down-regulated and proliferation is upregulated. Interestingly, some p53-dependent changes were subtype-specific. Basal-like cells lines demonstrated increased correlation with a Claudin-low breast cancer signature in presence of p53 KD, while luminal cell lines did not. Basal-like cell lines with p53 KD also exhibited decreased levels of apoptosis, while luminal cell-lines did not. Several miRs were differentially expressed in luminal vs. basal-like knock down cell lines including miR-134, miR-146a, and miR-181b. miR-146a was chosen for further analysis based on the most significant fold change. Antagomir knockdown of miR-146a ablated several p53-dependent phenotypic changes observed in basal-like cells, including increased population doubling times and decreased steady state apoptosis levels. The mechanism underlying these cellular phenotypes involves NF-kB signaling alterations, with downregulation of the extrinsic apoptotic pathway including TNFR, FADD, and TRADD. Antagomir-mediated knockdown of miR-146a restored expression of these components in basal-like breast cancer cell lines with p53 KD. This study documents that an alternate p53-dependent survival pathway exists for basal-like breast cancer cells with p53 loss, mediated by upregulation of miR-146a. Targeting miR-146a expression may have value for altering the aggressiveness of p53 mutant basal-like tumors.

Citation Format: Rupninder Sandhu, Jessica Rein, Monica D'Arcy, Melissa A. Troester. Over-expression of miR-146a in basal-like breast cancer cells confers enhanced tumorigenic potential in association with altered p53 status. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4196. doi:10.1158/1538-7445.AM2013-4196

Impact of tumor microenvironment and epithelial phenotypes on metabolism in breast cancer

PURPOSE

Cancer cells have altered metabolism, with increased glucose uptake, glycolysis, and biomass production. This study conducted genomic and metabolomic analyses to elucidate how tumor and stromal genomic characteristics influence tumor metabolism.

EXPERIMENTAL DESIGN

Thirty-three breast tumors and six normal breast tissues were analyzed by gene expression microarray and by mass spectrometry for metabolites. Gene expression data and clinical characteristics were evaluated in association with metabolic phenotype. To evaluate the role of stromal interactions in altered metabolism, cocultures were conducted using breast cancer cells and primary cancer-associated fibroblasts (CAF).

RESULTS

Across all metabolites, unsupervised clustering resulted in two main sample clusters. Normal breast tissue and a subset of tumors with less aggressive clinical characteristics had lower levels of nucleic and amino acids and glycolysis byproducts, whereas more aggressive tumors had higher levels of these Warburg-associated metabolites. While tumor-intrinsic subtype did not predict metabolic phenotype, metabolic cluster was significantly associated with expression of a wound response signature. In cocultures, CAFs from basal-like breast cancers increased glucose uptake and basal-like epithelial cells increased glucose oxidation and glycogen synthesis, suggesting interplay of stromal and epithelial phenotypes on metabolism. Cytokine arrays identified hepatocyte growth factor (HGF) as a potential mediator of stromal-epithelial interaction and antibody neutralization of HGF resulted in reduced expression of glucose transporter 1 (GLUT1) and decreased glucose uptake by epithelium.

CONCLUSIONS

Both tumor/epithelial and stromal characteristics play important roles in metabolism. Warburg-like metabolism is influenced by changes in stromal-epithelial interactions, including altered expression of HGF/Met pathway and GLUT1 expression.

Age-associated gene expression in normal breast tissue mirrors qualitative age-at-incidence patterns for breast cancer

BACKGROUND

Age is the strongest breast cancer risk factor, with overall breast cancer risk increasing steadily beginning at approximately 30 years of age. However, while breast cancer risk is lower among younger women, young women's breast cancer may be more aggressive. Although, several genomic and epidemiologic studies have shown higher prevalence of aggressive, estrogen-receptor negative breast cancer in younger women, the age-related gene expression that predisposes to these tumors is poorly understood. Characterizing age-related patterns of gene expression in normal breast tissues may provide insights on etiology of distinct breast cancer subtypes that arise from these tissues.

METHODS

To identify age-related changes in normal breast tissue, 96 tissue specimens from patients with reduction mammoplasty, ages 14 to 70 years, were assayed by gene expression microarray.

RESULTS

Significant associations between gene expression levels and age were identified for 802 probes (481 increased, 321 decreased with increasing age). Enriched functions included "aging of cells," "shape change," and "chemotaxis," and enriched pathways included Wnt/beta-catenin signaling, Ephrin receptor signaling, and JAK/Stat signaling. Applying the age-associated genes to publicly available tumor datasets, the age-associated pathways defined two groups of tumors with distinct survival.

CONCLUSION

The hazard rates of young-like tumors mirrored that of high-grade tumors in the Surveillance, Epidemiology, and End Results Program, providing a biologic link between normal aging and age-related tumor aggressiveness.

IMPACT

These data show that studies of normal tissue gene expression can yield important insights about the pathways and biologic pressures that are relevant during tumor etiology and progression.

Abstract 1680: Age-associated gene expression in normal breast tissue provide insights regarding associations between aging and aggressive tumor characteristics

Age is the strongest breast cancer risk factor, with overall breast cancer risk increasing steadily beginning at approximately 30 years of age. Though several genomic studies have characterized differences in the biology of tumors arising in younger vs. older women, understanding of age-related gene expression in the non-malignant tissue is lacking. Because non-malignant tissue represents the microenvironment and/or field from which the tumor arises, an improved characterization of the age-related change in normal breast may provide suggestions of important pathways in the etiology of distinct breast cancer subtypes. To identify age-related changes in the breast microenvironment, 96 normal tissue specimens from reduction mammoplasty patients ranging in age from 14 to 70 were assayed by gene expression microarray. Significant associations between gene expression levels and age were identified for 802 genes (481 increased and 321 decreased with increasing age). Enriched functions included ‘aging of cells’, ‘shape change’, and ‘chemotaxis’, and enriched pathways included Wnt/beta-catenin signaling, Ephrin Receptor Signaling, Oncostatin M signaling, and JAK/Stat Signaling. Applying the age-associated genes to publicly available tumor datasets, the age-associated pathways defined two groups of tumors with distinct survival. The poor prognosis tumor group shared features of ‘younger’ breast tissue gene expression, providing a biological link to qualitative patterns in age at incidence. Aggressive tumors common in younger women (such as ER negative and basal-like breast cancers) harbor gene expression patterns that reflect the normal tissue from which they arise. For the young, these signatures portend more aggressive disease. These data show that studies of normal tissue gene expression can yield important insights about the pathways and biological selection factors that are relevant during tumor progression.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1680. doi:1538-7445.AM2012-1680

High-resolution mapping and analysis of copy number variations in the human genome: a data resource for clinical and research applications

We present a database of copy number variations (CNVs) detected in 2026 disease-free individuals, using high-density, SNP-based oligonucleotide microarrays. This large cohort, comprised mainly of Caucasians (65.2%) and African-Americans (34.2%), was analyzed for CNVs in a single study using a uniform array platform and computational process. We have catalogued and characterized 54,462 individual CNVs, 77.8% of which were identified in multiple unrelated individuals. These nonunique CNVs mapped to 3272 distinct regions of genomic variation spanning 5.9% of the genome; 51.5% of these were previously unreported, and >85% are rare. Our annotation and analysis confirmed and extended previously reported correlations between CNVs and several genomic features such as repetitive DNA elements, segmental duplications, and genes. We demonstrate the utility of this data set in distinguishing CNVs with pathologic significance from normal variants. Together, this analysis and annotation provides a useful resource to assist with the assessment of CNVs in the contexts of human variation, disease susceptibility, and clinical molecular diagnostics.