Joseph Geradts

27-Hydroxycholesterol Links Hypercholesterolemia and Breast Cancer Pathophysiology

Cholesterol and Cancer Obesity and high cholesterol levels are associated with an increased risk of breast cancer in post-menopausal women. Nelson et al. (p. 1094) found that a specific metabolite of cholesterol, 27-hydroxycholesterol (27HC), promoted tumor growth and metastasis in mouse models of mammary cancer by serving as a partial agonist for the estrogen receptor and the liver X receptor. The most aggressive human breast cancers were found to express the highest level of the enzyme that converts cholesterol to 27HC, suggesting that 27HC produced within tumors (in addition to circulating 27HC) may contribute to tumorigenesis. The activity of a specific metabolite of cholesterol may help explain why obesity is a risk factor for breast cancer. Hypercholesterolemia is a risk factor for estrogen receptor (ER)–positive breast cancers and is associated with a decreased response of tumors to endocrine therapies. Here, we show that 27-hydroxycholesterol (27HC), a primary metabolite of cholesterol and an ER and liver X receptor (LXR) ligand, increases ER-dependent growth and LXR-dependent metastasis in mouse models of breast cancer. The effects of cholesterol on tumor pathology required its conversion to 27HC by the cytochrome P450 oxidase CYP27A1 and were attenuated by treatment with CYP27A1 inhibitors. In human breast cancer specimens, CYP27A1 expression levels correlated with tumor grade. In high-grade tumors, both tumor cells and tumor-associated macrophages exhibited high expression levels of the enzyme. Thus, lowering circulating cholesterol levels or interfering with its conversion to 27HC may be a useful strategy to prevent and/or treat breast cancer.

Intrinsic Breast Tumor Subtypes, Race, and Long-Term Survival in the Carolina Breast Cancer Study

Purpose: Previous research identified differences in breast cancer–specific mortality across 4 intrinsic tumor subtypes: luminal A, luminal B, basal-like, and human epidermal growth factor receptor 2 positive/estrogen receptor negative (HER2+/ER−). Experimental Design: We used immunohistochemical markers to subtype 1,149 invasive breast cancer patients (518 African American, 631 white) in the Carolina Breast Cancer Study, a population-based study of women diagnosed with breast cancer. Vital status was determined through 2006 using the National Death Index, with median follow-up of 9 years. Results: Cancer subtypes luminal A, luminal B, basal-like, and HER2+/ER− were distributed as 64%, 11%, 11%, and 5% for whites, and 48%, 8%, 22%, and 7% for African Americans, respectively. Breast cancer mortality was higher for participants with HER2+/ER− and basal-like breast cancer compared with luminal A and B. African Americans had higher breast cancer–specific mortality than whites, but the effect of race was statistically significant only among women with luminal A breast cancer. However, when compared with the luminal A subtype within racial categories, mortality for participants with basal-like breast cancer was higher among whites (HR = 2.0, 95% CI: 1.2–3.4) than African Americans (HR = 1.5, 95% CI: 1.0–2.4), with the strongest effect seen in postmenopausal white women (HR = 3.9, 95% CI: 1.5–10.0). Conclusions: Our results confirm the association of basal-like breast cancer with poor prognosis and suggest that basal-like breast cancer is not an inherently more aggressive disease in African American women compared with whites. Additional analyses are needed in populations with known treatment profiles to understand the role of tumor subtypes and race in breast cancer mortality, and in particular our finding that among women with luminal A breast cancer, African Americans have higher mortality than whites. Clin Cancer Res; 16(24); 6100–10. ©2010 AACR.

The Carolina Breast Cancer Study: integrating population-based epidemiology and molecular biology

SummaryThe integration of epidemiology and molecular biology provides a new strategy to identify additional risk factors for breast cancer and to better understand the role played by traditionally recognized risk factors. The Carolina Breast Cancer Study (CBCS) is a population-based, case-control study designed to identify causes of breast cancer among Caucasian and African-American women who are residents of a 24-county area of central and eastern North Carolina. Information on established and potential breast cancer risk factors is obtained by personal interviews. Blood samples are collected from all consenting participants. Medical record documentation and paraffin-embedded tumor specimens are obtained for all breast cancer patients. DNA from tumor tissue is tested for a variety of molecular alterations characteristic of breast cancer. Germline DNA from blood lymphocytes is evaluated for presence of alleles increasing susceptibility to breast cancer. Statistical analyses evaluate gene-environment interaction by exploring the associations between environmental/behavioral factors and breast cancer in relation to specific molecular alterations (germline and tumor). Results will help identify high-risk women, clarify causal pathways, and hopefully contribute to the prevention of breast cancer.

High focal adhesion kinase expression in invasive breast carcinomas is associated with an aggressive phenotype

Focal adhesion kinase (FAK) is a protein tyrosine kinase expressed in invasive breast cancer that regulates antiapoptotic signaling. We have examined FAK expression by immunohistochemistry using anti-FAK 4.47 in breast tumor samples from a large population-based, case–control study of women participating in the University of North Carolina Breast Specialized Programs of Research Excellence (SPORE), Carolina Breast Cancer Study. In this population, 629 formalin-fixed, paraffin-embedded tissue sections were stained for FAK and scored as high (3+ or 4+ intensity and ≥90% positive cells) or otherwise. High FAK expression was associated with poor prognostic indicators including high mitotic index (>10 mitoses per 10 consecutive high-power fields), nuclear grade 3, architectural grade 3, estrogen and progesterone receptor negative, and HER-2/neu overexpressed using CB11 antibody. The association of high FAK expression with HER-2/neu overexpression lends further support that HER-2/neu and FAK collaborate to promote tumorigenesis. The presence of strong FAK expression in many high grade, estrogen- and progesterone-negative breast carcinomas indicates that FAK may be an attractive target for therapeutic intervention.

Differential Gene Expression Patterns in HER2/neu-Positive and -Negative Breast Cancer Cell Lines and Tissues

Overexpression of the oncogene HER2/neu (c-erbB-2) occurs in up to 30% of breast cancers and is correlated with reduced survival, especially in node-positive disease. The aim of this study was to identify genes associated with the aggressive phenotype of HER2/neu-positive breast cancer cells using cDNA microarrays. RNA was extracted from three HER2/neu-positive and three HER2/neu-negative breast cancer cell lines. Pooled RNA was hybridized in duplicate to the breast specific microarray filters from Research Genetics containing 5184 unique cDNAs. Subsequently, a similar comparison was performed for pooled RNAs from 10 node-positive, ER-positive invasive ductal carcinomas, half of which were HER2/neu overexpressers. In HER2/neu overexpressing breast cancer cell lines, 90 (1.7%) genes were up-regulated and 46 (0.9%) were down-regulated, compared to cell lines with low HER2/neu protein levels. In contrast, in HER2/neu overexpressing primary breast cancers, more genes were down-regulated (N = 132, 2.5%) than up-regulated (N = 19, 0.4%). Many of the differentially expressed genes have previously not been known to play a role in human neoplasia, and some of them may represent novel tumor suppressor or oncogenes. No genes were up-regulated, and only a small number of genes were down-regulated both in cell lines and in carcinomas with high HER2/neu protein levels. These included transforming acidic coiled-coil containing protein 1, glycogen phosphorylase BB, complement 1q and one EST. The differential expression of select genes was confirmed by Northern blotting (trefoil factor 3) or by immunocytochemistry (glycogen phosphorylase BB, vimentin, KAI1). In an extended validation study, 18 of 41 ER-negative, but none of 46 ER-positive, breast carcinomas were found to express vimentin, and all but one of the vimentin-positive tumors were confined to the HER2/neu-negative subgroup (P = 0.0019). Our findings support an important role of the mammary stroma in determining the clinical breast cancer phenotype.

Ductal epithelial proliferations of the breast : a biological continuum? Comparative genomic hybridization and high-molecular-weight cytokeratin expression patterns

According to current concepts, benign proliferative breast disease (BPBD) is a direct precursor of breast cancer, in a spectrum ranging from ductal hyperplasia to overtly invasive carcinoma. In this study, comparative genomic hybridization (CGH) was used to screen ductal hyperplasia and other BPBD lesions and ductal carcinoma in situ (DCIS) for common genomic abnormalities, to test the relationship between these hyperplastic and neoplastic lesions. Immunohistochemistry for cytokeratin 5/6 was used as a diagnostic adjunct to distinguish ductal hyperplasia from DCIS. A total of 42 cases of BPBD comprising ductal hyperplasia of the usual type (n=14), papilloma (n=22), tubular adenoma (n=3), and adenosis (n=3), as well as 52 cases of DCIS, were studied. All cases of BPBD consistently displayed the presence of a subpopulation of cytokeratin 5/6‐expressing basal‐type cells within the proliferative lesion, whereas all of the non‐high‐grade and most of the high‐grade DCIS lesions lacked cytokeratin 5/6‐positive cells. Whereas gross genomic alterations, as determined by CGH, were undetectable in BPBD, distinct genetic changes characterized all cases of DCIS, with one exception. These results confirm the usefulness of cytokeratin 5/6 immunohistology in the diagnosis of BPBD and neoplastic breast lesions and support the view that BPBD and DCIS are not closely related entities and that BPBD is not an obligate direct precursor of DCIS. Copyright

Re-expression of p16 INK4a in mesothelioma cells results in cell cycle arrest, cell death, tumor suppression and tumor regression

Absence of expression of the p16IKN4a gene product is commonly observed in mesothelioma tumors and cell lines, while wild-type pRB expression is maintained. We have examined the biologic and potential therapeutic role of re-expressing p16INK4a gene product in mesothelioma cells and tumors. Following transduction with a p16INK4a expressing adenovirus (Adp16), over-expression of p16INK4a in mesothelioma cells resulted in cell cycle arrest, inhibition of pRB phosphorylation, diminished cell growth, and eventual death of the transduced cells. Expression of p16INK4a protein was accompanied by decreased expression of pRB as detected by immunoblot and immunohistochemistry. Experiments in mesothelioma xenografts demonstrated inhibition of tumor formation, tumor growth arrest and diminished tumor size and spread. p16INK4a gene product expression was also demonstrated in intraperitoneal xenografts of human mesothelioma cells. These results demonstrate that p16INK4a gene transfer may play a therapeutic role in the treatment of mesothelioma.

p16 Inactivation in Pancreatic Intraepithelial Neoplasias (PanINs) Arising in Patients with Chronic Pancreatitis

Patients with long-standing chronic pancreatitis are thought to be at increased risk of developing pancreatic ductal adenocarcinoma, but the mechanism for this increased risk is unknown. Since increasing evidence supports the notion that infiltrating pancreatic ductal adenocarcinomas arise from pancreatic intraepithelial lesions (PanINs), we sought to determine if patients with chronic pancreatitis harbor PanINs with alterations in tumor suppressor genes that are associated with infiltrating pancreatic ductal adenocarcinoma. We identified 122 patients with a diagnosis of chronic pancreatitis and 29 patients with a well-differentiated pancreatic endocrine tumor that underwent pancreatic surgery at the Johns Hopkins Hospital from 1985 to 1999. PanINs from each resection specimen were identified, graded, counted, and correlated with smoking and alcohol history. The expression patterns of p16 and Smad4 were determined in a subset of PanINs by immunohistochemistry, and the pattern of labeling compared with that seen in PanINs associated with infiltrating adenocarcinoma of the pancreas as identified in prior studies, and to PanINs associated with pancreatic endocrine tumor. Duct lesions were present in 80 of the 122 pancreata with chronic pancreatitis (66%). Of 405 duct lesions identified in the chronic pancreatitis group, 7.6% were reactive changes, 65.5% were PanIN-1A, 18% were PanIN-1B, 7.4% were PanIN-2, and 1.5% were PanIN-3. Within the pancreatic endocrine tumor group, 22 PanINs were identified: 15 PanIN-1A, 4 PanIN-1B, and 3 PanIN-2. There were significantly fewer high-grade PanINs in the pancreata with chronic pancreatitis than in pancreata with pancreatic adenocarcinoma (P < 0.0001). Within the chronic pancreatitis group, the 80 patients with PanINs were significantly older than the 42 patients without PanINs (mean age 57.0 ± 14.1 years vs. 50.9 ± 14.7 years, P = 0.01). Smoking history was not associated with PanIN prevalence or grade, but patients who reported a history of excessive alcohol consumption had fewer PanINs (25 of 44 harbored PanINs, 57%) than those who did not (54 of 74, 73%, P = 0.07). In the chronic pancreatitis group, 0% of PanIN-1A, 11% of the PanIN-1B, 16% of the PanIN-2, and 40% of the PanIN-3 lesions showed loss of p16 expression, whereas all of the PanINs from patients with an pancreatic endocrine tumor retained p16 expression. All of the PanINs analyzed from patients with chronic pancreatitis retained normal Smad4 expression. We conclude that a significant minority of PanINs arising in patients with chronic pancreatitis show loss of p16 expression. This alteration, common to pancreatic cancer-associated PanINs, may contribute to the predisposition of patients with chronic pancreatitis to develop pancreatic ductal adenocarcinoma.

Quantitative Optical Spectroscopy: A Robust Tool for Direct Measurement of Breast Cancer Vascular Oxygenation and Total Hemoglobin Content In vivo

We propose the use of a robust, biopsy needle-based, fiber-optic tool for routine clinical quantification of tumor oxygenation at the time of diagnostic biopsy for breast cancer. The purpose of this study was to show diffuse reflectance spectroscopy as a quantitative tool to measure oxygenation levels in the vascular compartment of breast cancers in vivo via an optical biopsy technique. Thirty-five patients undergoing surgical treatment for breast cancer were recruited for the study at Duke University Medical Center. Diffuse reflectance spectroscopy was performed on the tumors in situ before surgical resection, followed by needle-core biopsy of the optically measured tissue. Hemoglobin saturation and total hemoglobin content were quantified from 76 optical spectra-tissue biopsy pairs, consisting of 20 malignant, 23 benign, and 33 adipose tissues. Hemoglobin saturation in malignant tissues was significantly lower than nonmalignant tissues (P<0.002) and was negatively correlated with tumor size and pathologic tumor category (P<0.05). Hemoglobin saturation was positively correlated with total hemoglobin content in malignant tissues (P<0.02). HER2/neu-amplified tumors exhibited significantly higher total hemoglobin content (P<0.05) and significantly higher hemoglobin saturation (P<0.02), which is consistent with a model of increased angiogenesis and tumor perfusion promoted by HER2/neu amplification. Diffuse reflectance spectroscopy could aid in prognosis and prediction in breast cancer via quantitative assessment of tumor physiology at the time of diagnostic biopsy.

Tumor characteristics in African American and white women

AbstractBackground. Previous studies provide evidence that breast cancers occurring in different age and ethnic groups are not evenly distributed with regard to their biologic, pathologic and clinical characteristics. We evaluated the distributions of 11 pathological and biological variables between African-American (AA) and white patients and between three different age groups (20–39, 40–59 and 60–74 years). We examined whether racial differences existed across levels of age. Methods. Data were obtained from the Carolina Breast Cancer Study (CBCS), a population-based, case-control study of breast cancer in North Carolina. Eighty hundred and sixty one women with a first diagnosis of invasive breast cancer participated in Phase I of the CBCS. Diagnostic paraffin blocks were obtained from 807 cases. One representative block was scored for histologic type and grade (architectural, nuclear, mitotic and overall). Medical chart review yielded tumor size, lymph node status, distant metastases, stage, hormone receptor status (ER/PR) and DNA ploidy. Results. Pathologically advanced tumors (large size, high grade, high stage, ER/PR negative) were significantly more common in young and AA women. Racial differences varied by age. Among younger, AAs whites differed only with respect to ER/PR status, while among older women AAs and whites differed only with respect to stage at diagnosis. Conclusions. The results of this study confirm the presence of poorer prognosis breast cancer among AA and younger women. They also highlight the need for age and race to be considered together when evaluating pathologic and biologic characteristics of disease and when making inferences regarding tumor aggressiveness.