Endotrophin as a Biomarker for Severe Acute Kidney Injury and Major Adverse Kidney Events.

BACKGROUND: The search for novel biomarkers in acute kidney injury (AKI) continues, both in terms of being able to predict adverse events in AKI but also in terms of confirming pathogenic pathways as potential therapeutic targets. Endotrophin (ETP) is an emerging biomarker in a number of fibroinflammatory diseases. We sought to test the association of ETP with the development of major adverse kidney events (MAKE) in critically ill adult patients. METHOD: Single-center prospective study of critically ill adult patients with stage 2-3 AKI and patients without AKI. Serum ETP was measured early in the first 3 days of critical care admission, 5-7 days later, and in some patients, 4-6 weeks later. The primary outcome was MAKE assessed at hospital discharge, a composite of mortality, kidney replacement therapy at discharge, and estimated glomerular filtration rate reduction of ≥ 25% from baseline. RESULTS: Among 121 patients evaluated in this study, serum ETP was significantly higher in patients with AKI vs. those without (p<0.05). In multivariable logistic regression analysis, higher tertiles of ETP were significantly associated with MAKE at discharge, controlled for relevant covariates. Further, sustained elevations in ETP 5-7 days later, as opposed to reductions towards normal, were also associated with MAKE. In patients seen in the clinic 4-6 weeks post-AKI, ETP remained elevated. In the acute period, ETP levels correlated most with TNF-α and neutrophil gelatinase-associated lipocalin. CONCLUSION: Higher levels of serum ETP early in the ICU admission, as well as sustained elevations of ETP within a 5-7 day period, are associated with MAKE at hospital discharge. ETP is a potential biomarker of AKI-related outcomes and a promising therapeutic target to minimize sequelae of AKI.

Integrated analyses of single-cell transcriptomics identify metastasis-associated myeloid subpopulations in breast cancer lung metastasis.

Lung metastasis of breast cancer is closely associated with patient morbidity and mortality, which correlates with myeloid cells in the lung microenvironment. However, the heterogeneity and specificity of metastasis-associated myeloid cells have not been fully established in lung metastasis. Here, by integrating and analyzing single-cell transcriptomics, we found that myeloid subpopulations (Tppp3 + monocytes, Isg15 + macrophages, Ifit3 + neutrophils, and Il12b + DCs) play critical roles in the formation and development of the metastatic niche. Gene enrichment analyses indicate that several tumor-promoting pathways should be responsible for the process, including angiogenesis (Anxa1 and Anxa2 by Tppp3 + monocytes), immunosuppression (Isg15 and Cxcl10 by Isg15 + macrophages; Il12b and Ccl22 by Il12b + DCs), and tumor growth and metastasis (Isg15 and Isg20 by Ifit3 + neutrophils). Furthermore, we have validated these subpopulations in lung microenvironment of MMTV-PyVT transgenic mice and verified their association with poor progression of human breast cancer. Also, our results elucidated a crosstalk network among four myeloid subpopulations by cell-cell communication analysis. This study, therefore, highlights the crucial role of myeloid cells in lung metastasis and provides insights into underlying molecular mechanisms, which pave the way for therapeutic interventions in breast cancer metastasis to lung.

Endotrophin neutralization through targeted antibody treatment protects from renal fibrosis in a podocyte ablation model.

OBJECTIVE: Renal fibrosis is a hallmark for chronic kidney disease (CKD), and often leads to end stage renal disease (ESRD). However, limited interventions are available clinically to ameliorate or reverse renal fibrosis. METHODS: Herein, we evaluated whether blockade of endotrophin through neutralizing antibodies protects from renal fibrosis in the podocyte insult model (the "POD-ATTAC" mouse). We determined the therapeutic effects of endotrophin targeted antibody through assessing renal function, renal inflammation and fibrosis at histological and transcriptional levels, and podocyte regeneration. RESULTS: We demonstrated that neutralizing endotrophin antibody treatment significantly ameliorates renal fibrosis at the transcriptional, morphological, and functional levels. In the antibody treatment group, expression of pro-inflammatory and pro-fibrotic genes was significantly reduced, normal renal structures were restored, collagen deposition was decreased, and proteinuria and renal function were improved. We further performed a lineage tracing study confirming that podocytes regenerate as de novo podocytes upon injury and loss, and blockade of endotrophin efficiently enhances podocyte-specific marker expressions. CONCLUSION: Combined, we provide pre-clinical evidence supporting neutralizing endotrophin as a promising therapy for intervening with renal fibrosis in CKD, and potentially in other chronic fibro-inflammatory diseases.

Adipocyte mesenchymal transition contributes to mammary tumor progression.

Obesity is associated with increased cancer incidence and progression. However, the relationship between adiposity and cancer remains poorly understood at the mechanistic level. Here, we report that adipocytes from tumor-invasive mammary fat undergo de-differentiation to fibroblast-like precursor cells during tumor progression and integrate into the tumor microenvironment. Single-cell sequencing reveals that these de-differentiated adipocytes lose their original identities and transform into multiple cell types, including myofibroblast- and macrophage-like cells, with their characteristic features involved in immune response, inflammation, and extracellular matrix remodeling. The de-differentiated cells are metabolically distinct from tumor-associated fibroblasts but exhibit comparable effects on tumor cell proliferation. Inducing de-differentiation by Xbp1s overexpression promotes tumor progression despite lower adiposity. In contrast, promoting lipid-storage capacity in adipocytes through MitoNEET overexpression curbs tumor growth despite greater adiposity. Collectively, the metabolic interplay between tumor cells and adipocytes induces adipocyte mesenchymal transition and contributes to reconfigure the stroma into a more tumor-friendly microenvironment.

Deficient Caveolin-1 Synthesis in Adipocytes Stimulates Systemic Insulin-Independent Glucose Uptake via Extracellular Vesicles.

Caveolin-1 (cav1) is an important structural and signaling component of plasma membrane invaginations called caveolae and is abundant in adipocytes. As previously reported, adipocyte-specific ablation of the cav1 gene (ad-cav1 knockout [KO] mouse) does not result in elimination of the protein, as cav1 protein traffics to adipocytes from neighboring endothelial cells. However, this mouse is a functional KO because adipocyte caveolar structures are depleted. Compared with controls, ad-cav1KO mice on a high-fat diet (HFD) display improved whole-body glucose clearance despite complete loss of glucose-stimulated insulin secretion, blunted insulin-stimulated AKT activation in metabolic tissues, and partial lipodystrophy. The cause is increased insulin-independent glucose uptake by white adipose tissue (AT) and reduced hepatic gluconeogenesis. Furthermore, HFD-fed ad-cav1KO mice display significant AT inflammation, fibrosis, mitochondrial dysfunction, and dysregulated lipid metabolism. The glucose clearance phenotype of the ad-cav1KO mice is at least partially mediated by AT small extracellular vesicles (AT-sEVs). Injection of control mice with AT-sEVs from ad-cav1KO mice phenocopies ad-cav1KO characteristics. Interestingly, AT-sEVs from ad-cav1KO mice propagate the phenotype of the AT to the liver. These data indicate that ad-cav1 is essential for healthy adaptation of the AT to overnutrition and prevents aberrant propagation of negative phenotypes to other organs by EVs.

Serum levels of endotrophin are associated with nonalcoholic steatohepatitis.

BACKGROUND AND AIMS: There are no currently available biomarkers that can accurately indicate the presence of non-alcoholic steatohepatitis (NASH). We investigated the association between endotrophin, a cleavage product of collagen type 6α3, and disease severity in patients with non-alcoholic fatty liver disease (NAFLD). METHODS: We measured serum endotrophin levels in 211 patients with NAFLD and nine healthy controls. Liver biopsy data was available for 141 (67%) of the patients. Associations between endotrophin and the presence of NASH and advanced fibrosis were investigated alone and in combination with standard clinical parameters using logistic regression. RESULTS: A total of 211 patients were enrolled in this study, consisting of 108 (51%) men and 103 (49%) women with a mean age of 55.6 years. 58 (27%) of the patients had advanced fibrosis. Of those with biopsy data, 87 (62%) had NASH. Serum levels of endotrophin were significantly higher in patients with NAFLD than those in healthy controls (37[±12] vs. 17[±7] ng/mL, p<.001). Serum levels of endotrophin were also significantly higher in patients with NASH than in those without NASH (40[±12] vs. 32[±13] ng/mL, p<.001). A model using age, sex, body mass index and levels of alanine aminotransferase (ALT), glucose and endotrophin effectively predicted the presence of NASH in a derivation (AUROC 0.83, 95%CI = 0.74-0.92) and validation cohort (AUROC 0.71, 95%CI = 0.54-0.88). There was no significant association between serum levels of endotrophin and advanced fibrosis. CONCLUSIONS: These data suggest that serum endotrophin could be a valuable biomarker for diagnosing NASH, but not for detecting advanced fibrosis in NAFLD.

Human endotrophin as a driver of malignant tumor growth.

We have previously reported that the carboxy-terminal proteolytic cleavage product of the COL6α3 chain that we refer to as "endotrophin" has potent effects on transformed mammary ductal epithelial cells in rodents. Endotrophin (ETP) is abundantly expressed in adipose tissue. It is a chemoattractant for macrophages, exerts effects on endothelial cells and through epithelial-mesenchymal transition (EMT) enhances progression of tumor cells. In a recombinant form, human endotrophin exerts similar effects on human macrophages and endothelial cells as its rodent counterpart. It enhances EMT in human breast cancer cells and upon overexpression in tumor cells, the cells become chemoresistant. Here, we report the identification of endotrophin from human plasma. It is circulating at higher levels in breast cancer patients. We have developed neutralizing monoclonal antibodies against human endotrophin and provide evidence for the effectiveness of these antibodies to curb tumor growth and enhance chemosensitivity in a nude mouse model carrying human tumor cell lesions. Combined, the data validate endotrophin as a viable target for anti-tumor therapy for human breast cancer and opens the possibility for further use of these new reagents for anti-fibrotic approaches in liver, kidney, bone marrow and adipose tissue.

Adamts18 deficiency increases arterial thrombus formation associated with vascular defects in mice.

ADAMTS18 is a member of a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTSs) that are known for their crucial role in development, angiogenesis, inflammation and coagulation. It was previously reported that ADAMTS18 cleaved by thrombin induced platelet fragmentation, through which thrombus were dissolved. However, it remains unclear whether this represents a dominant physiologic mechanism controlling thrombus growth in vivo. Here, we used an established Adamts18 knockout (KO) mouse model to determine its function in thrombus formation. ADAMTS18 deficiency accelerated FeCl3-induced carotid artery thrombosis and aggravated postischemic cerebral infarction in mice. However, this accelerated thrombus phenotype in Adamts18 KO mice was not due to the lack of ADAMTS18-mediated-platelet fragmentation. Moreover, Adamts18 deficiency exerted little effects on mouse platelet functions. The underlying molecular mechanisms could be attributed in part to the abnormal vascular remodeling, including deficiency of carotid body (glomus) and aberrant carotid basal lamina. These results indicate a novel function of ADAMTS18 in vascular remodeling and associated thrombus formation.

Loss of Endothelial CXCR7 Impairs Vascular Homeostasis and Cardiac Remodeling After Myocardial Infarction: Implications for Cardiovascular Drug Discovery.

BACKGROUND: Genome-wide association studies identified the association of the CXCL12 genetic locus (which encodes the chemokine CXCL12, also known as stromal cell-derived factor 1) with coronary artery disease and myocardial infarction (MI). Unlike CXCR4, the classic receptor for CXCL12, the function of CXCR7 (the most recently identified receptor) in vascular responses to injury and in MI remains unclear. METHODS: Tissue expression of CXCR7 was examined in arteries from mice and humans. Mice that harbored floxed CXCR7 and Cdh5-promoter driven CreERT2 were treated with tamoxifen to induce endothelium-restricted deletion of CXCR7. The resulting conditional knockout mice and littermate controls were studied for arterial response to angioplasty wire injury and cardiac response to coronary artery ligation. The role of CXCR7 in endothelial cell proliferation and angiogenesis was determined in vitro with cells from mice and humans. The effects of adenoviral delivery of CXCR7 gene and pharmacological activation of CXCR7 were evaluated in mice subjected to MI. RESULTS: Injured arteries from both humans and mice exhibited endothelial CXCR7 expression. Conditional endothelial CXCR7 deletion promoted neointimal formation without altering plasma lipid levels after endothelial injury and exacerbated heart functional impairment after MI, with increased both mortality and infarct sizes. Mechanistically, the exacerbated responses in vascular and cardiac remodeling are attributable to the key role of CXCR7 in promoting endothelial proliferation and angiogenesis. Impressively, the impaired post-MI cardiac remodeling occurred with elevated levels of CXCL12, which was previously thought to mediate cardiac protection by exclusively engaging its cognate receptor, CXCR4. In addition, both CXCR7 gene delivery via left ventricular injection and treatment with a CXCR7 agonist offered cardiac protection after MI. CONCLUSIONS: CXCR7 represents a novel regulator of vascular homeostasis that functions in the endothelial compartment with sufficient capacity to affect cardiac function and remodeling after MI. Activation of CXCR7 may have therapeutic potential for clinical restenosis after percutaneous coronary intervention and for heart remodeling after MI.

Expression and purification of a novel therapeutic single-chain variable fragment antibody against BNP from inclusion bodies of Escherichia coli.

Abnormal brain natriuretic peptide (BNP) secretion is regarded as the dominating mechanism of cerebral salt wasting syndrome (CSW), which results from a renal loss of sodium and water during intracranial disease leading to hyponatremia. Scale preparation of therapeutic single-chain variable fragment (scFv) that can neutralize elevated circulating BNP may have potential value for clinical use. In this report, we used a recently isolated humanized anti-BNP scFv fragment (3C1) as model antibody (Ab) to evaluate the potential of scale production of this therapeutic protein. The truncated gene encoding for scFv fragment cloned in pET22b (+) was mainly overexpressed as inclusion bodies in Escherichia coli (E. coli) Rosetta (DE3) pLysS cells. The insoluble fragment was solubilized and purified by Ni-NTA agarose resin under denaturation conditions, and recovered via an effective refolding buffer containing 50 mM Tris-HCl, pH 8.0, 0.15 M NaCl, 1 mM EDTA, 0.5 M arginine, 2 mM GSH, 1 mM GSSG, and 5% glycerol. The refolded scFv fragment was concentrated by PEG20000, and dialyzed in PBS (containing 5% glycerol, pH 7.4). The final yield was approximately 10.2 mg active scFv fragment per liter of culture (3.4 g wet weight cells). The scFv fragment was more than 95% pure assessed by SDS-PAGE assay. Recombinant scFv fragment with His tag displayed its immunoreactivity with anti-His tag Ab by western blotting. ELISA showed the scFv fragment specifically bound to BNP, and it displayed similar activity as the traditional anti-BNP monoclonal Ab (mAb). Thus, the current strategy allows convenient small-scale production of this therapeutic protein.

Identification of breast cancer DNA methylation markers optimized for fine-needle aspiration samples.

BACKGROUND: Random periareolar fine-needle aspiration (RP-FNA) is increasingly used in trials of breast cancer prevention for biomarker assessments. DNA methylation markers may have value as surrogate endpoint biomarkers, but this requires identification of biologically relevant markers suitable for paucicellular, lymphocyte-contaminated clinical samples. METHODS: Unbiased whole-genome 5-aza-2'-deoxycytidine (5AZA)-induced gene expression assays, followed by several phases of qualitative and quantitative methylation-specific PCR (MSP) testing, were used to identify novel breast cancer DNA methylation markers optimized for clinical FNA samples. RESULTS: The initial 5AZA experiment identified 453 genes whose expression was potentially regulated by promoter region methylation. Informatics filters excluded 273 genes unlikely to yield useful DNA methylation markers. MSP assays were designed for 271 of the remaining genes and, ultimately, 33 genes were identified that were differentially methylated in clinical breast cancer samples, as compared with benign RP-FNA samples, and never methylated in lymphocytes. A subset of these markers was validated by quantitative multiplex MSP in extended clinical sample sets. Using a novel permutation method for analysis of quantitative methylation data, PSAT1, GNE, CPNE8, and CXCL14 were found to correlate strongly with specific clinical and pathologic features of breast cancer. In general, our approach identified markers methylated in a smaller subpopulation of tumor cells than those identified in published methylation array studies. CONCLUSIONS: Clinically relevant DNA methylation markers were identified using a 5AZA-induced gene expression approach. IMPACT: These breast cancer-relevant, FNA-optimized DNA methylation markers may have value as surrogate endpoint biomarkers in RP-FNA studies.

The clinical consequences of hemizygosity across 2 MB of 10q23 are restricted to Cowden syndrome.

Cowden syndrome is caused by germline mutations in PTEN and clinically characterized by hamartomas, macrocephaly, classic dermatologic stigmata, and an estimated 85 % lifetime risk of female breast cancer. A young woman with macrocephaly, tricholemmomas, AV malformations, and mammary papillomatosis was found to be hemizygous for PTEN in her germline DNA. Using MLPA, comparative genomic hybridization, and DNA sequencing, we identified a 2-Mb deletion in chromosome 10 spanning 344-kb centromeric and 1.7-Mb telomeric of PTEN. Her father who has a clinical history including macrocephaly, Hashimoto's thyroiditis, colonic polyposis, acral keratoses, and goiter was also found to have the same deletion. In benign breast tissue from the hemizygous female, PTEN protein expression was significantly reduced in luminal and stromal cells but present in the myoepithelium. Compared with a typical papilloma of the breast which had intense cytoplasmic PTEN staining, the majority of the patient's papilloma had significantly decreased PTEN expression while some cells had mislocalized perinuclear PTEN expression. In addition to PTEN, 22 other protein-coding genes were deleted including two predicted haploinsufficient genes and five additional genes that have previously been associated with hereditary predispositions to certain diseases. However, because all significant clinical features of the proband and her father are common to patients with genetic alterations in PTEN, the other 22 hemizygous protein-coding genes appear to be haplosufficient.

A humanized single-chain antibody against beta 3 integrin inhibits pulmonary metastasis by preferentially fragmenting activated platelets in the tumor microenvironment.

Platelets play a supportive role in tumor metastasis. Impairment of platelet function within the tumor microenvironment may provide a clinically useful approach to inhibit metastasis. We developed a novel humanized single-chain antibody (scFv Ab) against integrin GPIIIa49-66 (named A11) capable of lysing activated platelets. In this study, we investigate the effect of A11 on the development of pulmonary metastases. In the Lewis lung carcinoma (LLC) metastatic model, A11 decreases the mean number of surface nodules and mean volume of pulmonary nodules. It protects against lung metastases in a time window that extended 4 hours before and 4 hours after the IV injection of LLCs. Coinjection of GPIIIa49-66 albumin reverses the antimetastatic activity of A11 in the B16 melanoma model, consistent with the pathophysiologic relevance of the platelet GPIIIa49-66 epitope. Significantly, A11 had no effect on angiogenesis using both in vitro and in vivo assays. The underlying molecular mechanisms are a combination of inhibition of each of the following interactions: between activated platelets and tumor cells, platelets and endothelial cells, and platelets and monocytes, as well as disaggregation of an existing platelet/tumor thrombus. Our observations may provide a novel antimetastatic strategy through lysing activated platelets in the tumor microenvironment using humanized anti-GPIIIa49-66 scFv Ab.

Optimized refolding and characterization of active C-terminal ADAMTS-18 fragment from inclusion bodies of Escherichia coli.

The human ADAMTS-18 (a disintegrin and metalloproteinase with thrombospondin type-1 modules 18) is a new member of the ADAMTS family. The C-terminal ADAMTS-18 fragment is highly effective at promoting platelet thrombus dissolution in murine model of ischemic stroke, showing significant clinical relevance. In this report, the C-terminal ADAMTS-18 fragment with a GST tag (named rADAMTS-351) was overexpressed mainly as inclusion bodies in Escherichia coli BL21 (DE3) pLysS. The insoluble inclusion body was solubilized and reactivated via a refolding procedure. The optimal buffers for refolding rADAMTS-351 was composed of 50 mM Tris-HCl buffer at pH 8.0, 5 mM EDTA, 150 mM NaCl, 0.1 mM DTT, 1 mM GSH, and 0.2 mM GSSG. The refolded rADAMTS-351 was dialyzed and further purified by glutathione-agarose beads. The purity of the final product reached 98% as evaluated by SDS-PAGE and Coomassie Brilliant Blue R250 staining. The recombinant protein displayed its immunoreactivity with anti-C-terminal ADAMTS-18 antibodies by Western blotting. Mass spectroscopic analysis indicated a molecular mass of 65,327 Da as theoretically expected. Purified rADAMTS-351 displayed its bioactivity by inducing platelet fragmentation, which ranged from 81-96% compared to active C-terminal ADAMTS-18 standards. The expression and refolding strategy described in this study allows convenient small-scale production of rADAMTS-351 with biological function and therapeutic potential.

A polyclonal antibody against active C-terminal ADAMTS-18 fragment.

The human ADAMTS-18, a disintegrin and metalloproteinase with thrombospondin type-1 modules 18, is a secreted Zn-metalloproteinase. The C-terminal 385-amino acid fragment of ADAMTS-18 (AD18C) is highly effective at promoting platelet thrombus dissolution in vivo. Therefore, polyclonal antibody (pAb) against AD18C fragment should be able to keep platelet thrombus stability, which has direct clinical relevance. In this report, pAb against AD18C fragment was generated from rabbit immunized with AD18C recombinant protein (rAD18C). The pAb showed specific binding with rAD18C and natural ADAMTS-18 protein by ELISA and Western blot assay. It shortens the mouse tail bleeding time in a dose-dependent manner. Thus, anti-AD18C pAb contributes to the regulation of platelet thrombus stability.

Tamoxifen downregulates ets oncogene family members ETV4 and ETV5 in benign breast tissue: implications for durable risk reduction.

Five years of tamoxifen reduces breast cancer risk by nearly 50% but is associated with significant side effects and toxicities. A better understanding of the direct and indirect effects of tamoxifen in benign breast tissue could elucidate new mechanisms of breast carcinogenesis, suggest novel chemoprevention targets, and provide relevant early response biomarkers for phase II prevention trials. Seventy-three women at increased risk for breast cancer were randomized to tamoxifen (20 mg daily) or placebo for 3 months. Blood and breast tissue samples were collected at baseline and posttreatment. Sixty-nine women completed all study activities (37 tamoxifen and 32 placebo). The selected biomarkers focused on estradiol and IGFs in the blood; DNA methylation and cytology in random periareolar fine-needle aspirates; and tissue morphometry, proliferation, apoptosis, and gene expression (microarray and reverse transcriptase PCR) in the tissue core samples. Tamoxifen downregulated Ets oncogene transcription factor family members ETV4 and ETV5 and reduced breast epithelial cell proliferation independent of CYP2D6 genotypes or effects on estradiol, ESR1, or IGFs. Reduction in proliferation was correlated with downregulation of ETV4 and DNAJC12. Tamoxifen reduced the expression of ETV4- and ETV5-regulated genes implicated in epithelial-stromal interaction and tissue remodeling. Three months of tamoxifen did not affect breast tissue composition, cytologic atypia, preneoplasia, or apoptosis. A plausible mechanism for the chemopreventive effects of tamoxifen is restriction of lobular expansion into stroma through downregulation of ETV4 and ETV5. The human equivalent of murine multipotential progenitor cap cells of terminal end buds may be the primary target.

DNA methylation in benign breast epithelium in relation to age and breast cancer risk.

BACKGROUND: Many established breast cancer risk factors are related to the timing and duration of exposure to reproductive hormones, which are known to drive breast epithelial cell proliferation. The epigenetic molecular clock hypothesis suggests that CpG island methylation records the cell division history of benign epithelium. In proliferative epithelium, such as breast, this may provide an individualized cell-based measure of cancer risk. METHODS: Methylation of cyclin D2, APC, HIN1, RASSF1A, and RAR-beta2 was measured by quantitative multiplex methylation-specific PCR in 290 benign and malignant breast epithelial cell samples obtained by palpation-directed fine-needle aspiration biopsy from 164 women. Univariate, multivariate, and unsupervised cluster analysis was used to establish the relationship between TSG methylation and a personal history of breast cancer, predicted breast cancer risk, and specific breast cancer risk factors. RESULTS: RASSF1A methylation was highly correlated with breast cancer risk [odds ratio (OR), 5.28; 95% confidence interval (95% CI), 1.95-14.32; P = 0.001], atypical cytology (OR, 4.11; 95% CI, 1.30-12.98; P = 0.016), and benign breast disease requiring biopsy (OR, 6.12; 95% CI, 1.41-26.51; P = 0.016). RASSF1A methylation increased linearly between ages 32 and 55. Increasing parity was associated with decreased APC methylation. CONCLUSIONS: TSG methylation increases in benign breast epithelium with increasing age. Because it is independently related to a personal history of benign or malignant breast disease and to predicted breast cancer risk, it may have value for breast cancer risk stratification and as a surrogate endpoint marker in prevention trials.

Atypia and DNA methylation in nipple duct lavage in relation to predicted breast cancer risk.

BACKGROUND: Tumor suppressor gene (TSG) methylation is identified more frequently in random periareolar fine needle aspiration samples from women at high risk for breast cancer than women at lower risk. It is not known whether TSG methylation or atypia in nipple duct lavage (NDL) samples is related to predicted breast cancer risk. METHODS: 514 NDL samples obtained from 150 women selected to represent a wide range of breast cancer risk were evaluated cytologically and by quantitative multiplex methylation-specific PCR for methylation of cyclin D2, APC, HIN1, RASSF1A, and RAR-beta2. RESULTS: Based on methylation patterns and cytology, NDL retrieved cancer cells from only 9% of breasts ipsilateral to a breast cancer. Methylation of >/=2 genes correlated with marked atypia by univariate analysis, but not multivariate analysis, that adjusted for sample cellularity and risk group classification. Both marked atypia and TSG methylation independently predicted abundant cellularity in multivariate analyses. Discrimination between Gail lower-risk ducts and Gail high-risk ducts was similar for marked atypia [odds ratio (OR), 3.48; P = 0.06] and measures of TSG methylation (OR, 3.51; P = 0.03). However, marked atypia provided better discrimination between Gail lower-risk ducts and ducts contralateral to a breast cancer (OR, 6.91; P = 0.003, compared with methylation OR, 4.21; P = 0.02). CONCLUSIONS: TSG methylation in NDL samples does not predict marked atypia after correcting for sample cellularity and risk group classification. Rather, both methylation and marked atypia are independently associated with highly cellular samples, Gail model risk classifications, and a personal history of breast cancer. This suggests the existence of related, but independent, pathogenic pathways in breast epithelium.

Role of physical activity in modulating breast cancer risk as defined by APC and RASSF1A promoter hypermethylation in nonmalignant breast tissue.

Physical activity reduces breast cancer risk. Promoter hypermethylation of the tumor suppressor genes APC and RASSF1A, which is potentially reversible, is associated with breast cancer risk. We conducted a cross-sectional study in 45 women without breast cancer to determine the association of physical activity with promoter hypermethylation of APC and RASSF1A in breast tissue. We used quantitative methylation-specific PCR to test the methylation status of APC and RASSF1A, and questionnaires to assess study covariates and physical activity (measured in metabolic equivalent hours per week). In univariate analyses, the study covariate, benign breast biopsy number, was positively associated with promoter hypermethylation of APC (P = 0.01) but not RASSF1A. Mulitvariate logistic regression indicated that, although not significant, physical activities for a lifetime [odds ratio (OR), 0.57; 95% confidence interval (95% CI), 0.22-1.45; P = 0.24], previous 5 years (OR, 0.62; 95% CI, 0.34-1.12; P = 0.11), and previous year (OR, 0.72; 95% CI, 0.43-1.22; P = 0.22) were inversely related to promoter hypermethylation of APC but not RASSF1A for all physical activity measures. Univariate logistic regression indicated that physical activities for a lifetime, previous 5 years, and previous year were inversely associated with benign breast biopsy number, and these results were approaching significance for lifetime physical activity (OR, 0.41; 95% CI, 0.16-1.01; P = 0.05) and significant for physical activity in the previous 5 years (OR, 0.57; 95% CI, 0.34-0.94; P = 0.03). The study provides indirect evidence supporting the hypothesis that physical activity is inversely associated with promoter hypermethylation of tumor suppressor genes, such as APC, in nonmalignant breast tissue.