Factors associated with obtaining nipple aspirate fluid: analysis of 1428 women and literature review

Nipple Aspirate Fluid at a Glance

Simple Summary

Nipple aspirate fluid (NAF) is a promising source of markers for detection of breast cancer. NAF can be acquired via the nipple by aspiration using a suction device, which is well tolerated by women. Future possible applications of biomarkers for breast cancer derived from NAF could be (1) as a detection tool to identify the initiation of the cancer development process, (2) as an additional tool next to imaging (mammography and breast magnetic resonance imaging) or (3) as a replacement tool for when imaging is not advisable for women, such as during pregnancy and breastfeeding. With this paper, we present a narrative review and perspectives of NAF research at a glance.

Abstract

Nipple aspirate fluid (NAF) is an intraductal mammary fluid that, because of its close proximity to and origin from the tissue from which breast cancer originates, is a promising source of biomarkers for early breast cancer detection. NAF can be non-invasively acquired via the nipple by aspiration using a suction device; using oxytocin nasal spray helps increase yield and tolerability. The aspiration procedure is generally experienced as more tolerable than the currently used breast imaging techniques mammography and breast magnetic resonance imaging. Future applications of NAF-derived biomarkers include their use as a tool in the detection of breast carcinogenesis at its earliest stage (before a tumor mass can be seen by imaging), or as a supporting diagnostic tool for imaging, such as when imaging is less reliable (to rule out false positives from imaging) or when imaging is not advisable (such as during pregnancy and breastfeeding). Ongoing clinical studies using NAF samples will likely shed light on NAF’s content and clinical potential. Here, we present a narrative review and perspectives of NAF research at a glance.

Prediagnostic breast milk DNA methylation alterations in women who develop breast cancer

Prior candidate gene studies have shown tumor suppressor DNA methylation in breast milk related with history of breast biopsy, an established risk factor for breast cancer. To further establish the utility of breast milk as a tissue-specific biospecimen for investigations of breast carcinogenesis, we measured genome-wide DNA methylation in breast milk from women with and without a diagnosis of breast cancer in two independent cohorts. DNA methylation was assessed using Illumina HumanMethylation450k in 87 breast milk samples. Through an epigenome-wide association study we explored CpG sites associated with a breast cancer diagnosis in the prospectively collected milk samples from the breast that would develop cancer compared with women without a diagnosis of breast cancer using linear mixed effects models adjusted for history of breast biopsy, age, RefFreeCellMix cell estimates, time of delivery, array chip and subject as random effect. We identified 58 differentially methylated CpG sites associated with a subsequent breast cancer diagnosis (q-value <0.05). Nearly all CpG sites associated with a breast cancer diagnosis were hypomethylated in cases compared with controls and were enriched for CpG islands. In addition, inferred repeat element methylation was lower in breast milk DNA from cases compared to controls, and cases exhibited increased estimated epigenetic mitotic tick rate as well as DNA methylation age compared with controls. Breast milk has utility as a biospecimen for prospective assessment of disease risk, for understanding the underlying molecular basis of breast cancer risk factors and improving primary and secondary prevention of breast cancer.

Genetic Determinants of Nipple Aspiration Fluid Yield

PURPOSE

Nipple aspiration fluid (NAF) is a non-invasively-acquired biosample that can provide a window into the breast environment, but NAF yield is highly variable. Its determinants must be better understood for studies of breast cancer risk. The wet earwax phenotype was identified as one determinant of NAF yield in the 1970s, and is linked to single nucleotide polymorphisms (SNPs) in the ATP-binding cassette transporter gene ABCC11. We have investigated this, as well as SNPs in the prolactin (PRL) and prolactin receptor (PRLR) genes, in relation to NAF yield.

METHODS

DNA was extracted from white blood cells of 557 NAF yielders and 359 non-yielders, and was used to genotype ABCC11 (rs17822931), PRL (rs849870, rs849872, rs849886, rs2244502, rs1341239), and PRLR (rs37364, rs34024951, rs1610218, rs9292575, rs7718468) using Taqman genotyping assay. The association between NAF yield and each single SNP was analyzed using logistic regression adjusting for age, race, and menopausal status.

RESULTS

ABCC11 rs17822931 showed a negative association with NAF yield [odds ratio (OR) 0.66, 95 % confidence interval (CI) 0.49-0.88; p = 0.004]. The PRL rs849870 and the haplotype combination with other SNPs showed a marginal association with NAF yield. In addition, the years since last birth also showed negative association with NAF yielding (OR 0.98, 95 % CI 0.96-0.99; p = 0.001). The combination of the years since last birth with ABCC11 SNP revealed significant interaction between reproductive factor and genetic factor.

CONCLUSIONS

Our results confirmed the association between NAF yield and earwax phenotype through ABCC11 genotype. Combined with the recency of last birth, ABCC11 genotype should be considered in the design of studies utilizing NAF as a biosample.

Hormonal determinants of nipple aspirate fluid yield among breast cancer cases and screening controls

BACKGROUND

Nipple aspiration fluid (NAF) use as a biosample is limited by the variable yield across studies. We investigated the endocrine determinants of yield in an ongoing breast cancer case-control study.

METHODS

One-hundred and eighteen women yielding ≥2 μL NAF and 120 non-yielders were included; serum hormones were measured; differences in median hormones were assessed using the Wilcoxon rank-sum test. ORs and 95% confidence intervals (95% CI) for yielder status relative to hormone levels were estimated using logistic regression, adjusting for parity and lactation, and, in premenopausal women, menstrual cycle phase (MCP).

RESULTS

Prolactin concentrations were higher in yielders than non-yielders (premenopausal: 7.6 and 2.5 ng/mL, P < 0.01; postmenopausal 5.3 and 2.2 ng/mL; P < 0.01). Among premenopausal-yielders, estradiol was lower (64.3 vs. 90.5 pg/mL, MCP-adjusted P = 0.02). In separate menopausal status and parity-adjusted models, significant case-control differences persisted in prolactin: case OR 1.93 (95% CI, 1.35-2.77), control OR 1.64 (95% CI, 1.17-2.29). Premenopausal control yielders had higher progesterone (OR, 1.70; 95% CI, 1.18-2.46) and sex-hormone binding-globulin (OR, 2.09; 95% CI, 1.08-4.05) than non-yielders. Among parous women, further adjustment for lactation suggested a stronger positive association of serum prolactin with yield in cases than controls.

CONCLUSION

NAF-yielders show higher prolactin than non-yielders, regardless of menopause and parity; implications of this and other endocrine differences on NAF biomarkers of breast cancer risk deserve further study.

IMPACT

NAF yield is associated with a distinct endocrine environment that must be considered in studies of NAF-based breast cancer risk markers.

Cancer proteomics

Cancer presents high mortality and morbidity globally, largely due to its complex and heterogenous nature, and lack of biomarkers for early diagnosis. A proteomics study of cancer aims to identify and characterize functional proteins that drive the transformation of malignancy, and to discover biomarkers to detect early-stage cancer, predict prognosis, determine therapy efficacy, identify novel drug targets, and ultimately develop personalized medicine. The various sources of human samples such as cell lines, tissues, and plasma/serum are probed by a plethora of proteomics tools to discover novel biomarkers and elucidate mechanisms of tumorigenesis. Innovative proteomics technologies and strategies have been designed for protein identification, quantitation, fractionation, and enrichment to delve deeper into the oncoproteome. In addition, there is the need for high-throughput methods for biomarker validation, and integration of the various platforms of oncoproteome data to fully comprehend cancer biology.

The volume of nipple aspirate fluid is not affected by 6 months of treatment with soy foods in premenopausal women

Based on the hypothesis that soy food consumption may influence breast tissue activity, we examined its effect on the production of nipple aspirate fluid (NAF), a possible indicator of breast cancer risk. Of 310 premenopausal women screened, 112 (36%) produced at least 10 μL of NAF, the minimum for study participation. In a crossover design, we randomized 96 women to 2 groups who, in reverse order, consumed a high-soy diet with 2 soy servings/d (1 serving = 177 mL soy milk, 126 g tofu, or 23 g soy nuts) and a low-soy diet with <3 servings/wk of soy for 6 mo each separated by a 1-mo washout period. During each diet period, 3 NAF samples were obtained (baseline and 3 and 6 mo) using a FirstCyte Aspirator and 4 urine samples (baseline and 1, 3, and 6 mo) were analyzed for isoflavonoids by liquid chromatography tandem MS. Adherence to the study protocol according to 24-h dietary recalls and urinary isoflavonoid excretion was high. The drop-out rate was 15% (n = 14); 82 women completed the intervention. The 2 groups produced similar mean NAF volumes at baseline (P = 0.95) but differed in age and previous soy intake and in their response to the intervention (P = 0.03). In both groups, NAF volume decreased during the first 3 mo of the high-soy diet period and returned to baseline at 6 mo, but there was no effect of the high-soy diet on NAF volume (P = 0.50 for diet; P-interaction = 0.21 for diet with time). Contrary to an earlier report, soy foods in amounts consumed by Asians did not increase breast tissue activity as assessed by NAF volume.

Challenges to developing proteomic-based breast cancer diagnostics

Over the past decade, multiple genetic and histological approaches have accelerated development of new breast cancer diagnostics and treatment paradigms. Multiple distinct genetic subtypes of breast cancers have been defined, and this has progressively led toward more personalized medicine in regard to treatment options. There still remains a deficiency in the development of molecular diagnostic assays that can be used for breast cancer detection and pretherapy clinical decisions. In particular, the type of cancer-specific biomarker typified by a serum or tissue-derived protein. Progress in this regard has been minimal, especially in comparison to the rapid advancements in genetic and histological assays for breast cancers. In this review, some potential reasons for this large gap in developing protein biomarkers will be discussed, as well as new strategies for improving these approaches. Improvements in the study design of protein biomarker discovery strategies in relation to the genetic subtypes and histology of breast cancers is also emphasized. The current successes in use of genetic and histological assays for breast cancer diagnostics are summarized, and in that context, the current limitations of the types of breast cancer-related clinical samples available for protein biomarker assay development are discussed. Based on these limitations, research strategies emphasizing identification of glycoprotein biomarkers in blood and MALDI mass spectrometry imaging of tissues are described.

Successful oxytocin-assisted nipple aspiration in women at increased risk for breast cancer

The high rate of interval malignancies urges for new screening methods for women at high risk for breast cancer. Nipple aspiration provides direct access to the breast tissue and its DNA, and therefore is a likely candidate, but clinical applications have been limited by the failure to obtain nipple aspiration fluid from most women. We performed oxytocin-assisted nipple aspiration in 90 women at increased risk for breast cancer based on family history or genetic test results (n = 63) and/or previous breast cancer (n = 34). Nipple fluid was obtained from 81/90 women (90%) and bilaterally in 77%. Mean discomfort rating was 0.6 (on a 0–10 scale), which was significantly lower than for mammography or MRI. These findings suggest that a new tool for biomarker detection in oxytocin-assisted nipple fluid of women at high risk for breast cancer is at hand.

Cellular and hormonal content of breast nipple aspirate fluid in relation to the risk of breast cancer

In research settings, the measurement of serum and urine hormone concentrations has shown modest positive relationships with breast cancer risk in postmenopausal women. However, the local production of sex steroids in the breast is a significant contributor to the hormonal environment of the breast. Nipple aspiration fluid provides a window into this environment and allows the measurement of hormone and protein content which may show stronger relations to breast cancer risk, and therefore enable both more accurate risk assessment, and the use of preventive measures directed to the lowering of local breast hormonal exposure.

Nipple Aspirate Fluid Proteome of Healthy Females and Patients with Breast Cancer

Background: The ductal/alveolar system of the female breast constantly secretes and reabsorbs fluid in nonpregnant/nonlactating women. This fluid, referred to as nipple aspirate fluid (NAF), can be obtained by a noninvasive procedure and it is part of the microenvironment where more than 95% of breast cancers arise.

Methods: Using an Orbitrap® mass analyzer coupled to a linear ion trap, we performed an in-depth proteomic analysis of NAF samples obtained from 3 healthy individuals and 3 patients with breast cancer. Multiple fractionation methods such as size-exclusion and anion-exchange chromatography were applied for protein separation before mass spectrometric analysis.

Results: We identified more than 800 unique proteins in total, generating the most extensive NAF proteome thus far. Using gene ontology, we classified the identified proteins by their subcellular localization and found that more than 50% were extracellular or plasma membrane proteins. By searching against the Plasma Proteome Database, we confirmed that 40% of the proteins were also found in the plasma. Unigene database searching for transcripts of the proteins not found in the plasma revealed that the vast majority were expressed in the mammary gland.

Conclusions: Our extensive proteome database for NAF may be helpful in the identification of novel cancer biomarkers.

Tissue culture-based breast cancer biomarker discovery platform

Current cancer biomarkers suffer from low diagnostic sensitivity and specificity and have not yet made a major impact on reducing cancer burden. Proteomic methods based on mass spectrometry have matured significantly over the past few years and hold promise to deliver candidate markers for diagnosis, prognosis or monitoring therapeutic response. Because of the complex nature of biological fluids such as plasma, biomarker discovery efforts using proteomics have not as yet delivered any novel tumor markers. Recently, there has been a rise in the number of publications utilizing a cell culture-based model of cancer to identify novel candidate tumor markers. The secretome of cancer cell lines constitutes an important class of proteins that can act locally and systemically in the body. Secreted proteins, in addition to serving as serological markers, play a central role in physiology and pathophysiology. In this review, we focus on the proteomics of breast cancer and the different strategies to mine for biomarkers, with particular emphasis on a cell culture-based model developed in our laboratory.

Nutrients and nipple aspirate fluid composition: the breast microenvironment regulates protein expression and cancer aetiology

The aetiology of breast cancer is complex and multifactorial, and may include diet and xenobiotic compounds. A change in diet affects nutrient levels in blood, but to what extent diet can affect micronutrient concentrations in the breast is not yet well established. Breast nipple aspirate fluids (NAF) can be non-invasively obtained from the breast in most women; it represents a biological tool to assess metabolic changes in the breast ductal microenvironment. A wide variation in biomolecular and hormonal composition of NAFs collected from healthy and breast cancer patient may be due to genetic and nutritional factors; however, micro- and macro-nutrients may influence the secretory status of these women, thus NAF composition and risk of breast carcinoma. The aim of this overview is to highlight the detrimental/beneficial role that diet-related compounds in nipple aspirate fluid can have in breast cancer risk.

Dietary intake of lactose as a strong predictor for secretor status of nipple aspirate fluid in healthy premenopausal nonlactating women

PURPOSE

Nipple aspirate fluid (NAF) is considered a potential source for discovering breast cancer biomarkers. However, the success rate of obtaining NAF was reported to vary from 48% to 77%, and mechanisms for its secretion are not fully understood. The purpose of this study was to investigate dietary, demographic, reproductive, hormonal, and anthropometric factors that are associated with the ability to obtain NAF by aspiration (secretor status) from premenopausal women.

STUDY DESIGN

NAF procedures were attempted for women who were 30 to 40 years old, not pregnant, not breast-feeding, and not taking contraceptive medications.

RESULTS

Compared with nonsecretors, secretors of NAF consumed significantly more dietary lactose (mainly from milk), were more likely to be parous, were older at first and last childbirth, breast-fed their babies for a longer period of time, and had an earlier menarche and lower plasma concentrations of 17beta-estradiol (P < 0.05). Using multivariate logistic regression models, higher dietary intake of lactose [odds ratio (OR), 2.7; 95% confidence interval (95% CI), 1.5-4.8], earlier menarche (OR, 0.8; 95% CI, 0.7-1.0), being parous (OR, 2.3; 95% CI, 1.0-5.6), and being older at first childbirth (OR, 1.5; 95% CI, 1.0-2.1) were found to be independent and positive predictors for being a secretor of NAF.

CONCLUSIONS

These findings suggest that dietary intake of lactose, a modifiable factor, may be used to change the NAF secretor status of women. This finding may facilitate the use of NAF as a diagnostic material for detecting breast diseases.

Facile whole mitochondrial genome resequencing from nipple aspirate fluid using MitoChip v2.0

Background

Mutations in the mitochondrial genome (mtgenome) have been associated with many disorders, including breast cancer. Nipple aspirate fluid (NAF) from symptomatic women could potentially serve as a minimally invasive sample for breast cancer screening by detecting somatic mutations in this biofluid. This study is aimed at 1) demonstrating the feasibility of NAF recovery from symptomatic women, 2) examining the feasibility of sequencing the entire mitochondrial genome from NAF samples, 3) cross validation of the Human mitochondrial resequencing array 2.0 (MCv2), and 4) assessing the somatic mtDNA mutation rate in benign breast diseases as a potential tool for monitoring early somatic mutations associated with breast cancer.

Methods

NAF and blood were obtained from women with symptomatic benign breast conditions, and we successfully assessed the mutation load in the entire mitochondrial genome of 19 of these women. DNA extracts from NAF were sequenced using the mitochondrial resequencing array MCv2 and by capillary electrophoresis (CE) methods as a quality comparison. Sequencing was performed independently at two institutions and the results compared. The germline mtDNA sequence determined using DNA isolated from the patient's blood (control) was compared to the mutations present in cellular mtDNA recovered from patient's NAF.

Results

From the cohort of 28 women recruited for this study, NAF was successfully recovered from 23 participants (82%). Twenty two (96%) of the women produced fluids from both breasts. Twenty NAF samples and corresponding blood were chosen for this study. Except for one NAF sample, the whole mtgenome was successfully amplified using a single primer pair, or three pairs of overlapping primers. Comparison of MCv2 data from the two institutions demonstrates 99.200% concordance. Moreover, MCv2 data was 99.999% identical to CE sequencing, indicating that MCv2 is a reliable method to rapidly sequence the entire mtgenome. Four NAF samples contained somatic mutations.

Conclusion

We have demonstrated that NAF is a suitable material for mtDNA sequence analysis using the rapid and reliable MCv2. Somatic mtDNA mutations present in NAF of women with benign breast diseases could potentially be used as risk factors for progression to breast cancer, but this will require a much larger study with clinical follow up.

Epithelial cells in nipple aspirate fluid and subsequent breast cancer risk: a historic prospective study

Background

Past studies have shown that women with abnormal cytology or epithelial cells in nipple aspirate fluid (NAF) have an increased relative risk (RR) of breast cancer when compared to women from whom NAF was attempted but not obtained (non-yielders). This study analyzed NAF results from a group of women seen in a breast clinic between 1970–1991 (N = 2480). Our analysis presented here is an aggregate of two sub-groups: women with questionnaire data (n = 712) and those with NAF visits beginning in 1988 (n = 238), the year in which cancer case information was uniformly collected in California.

Methods

Cytological classification was determined for a group of 946 women using the most abnormal epithelial cytology observed in fluid specimens. Breast cancer incidence and mortality status was determined through June 2006 using data from the California Cancer Registry, California Vital Statistics and self-report. We estimated odd ratios (ORs) for breast cancer using logistic regression analysis, adjusting for age. We analyzed breast cancer risk related to abnormality of NAF cytology using non-yielders as the referent group and breast cancer risk related to the presence or absence of epithelial cells in NAF, using non-yielders/fluid without epithelial cells as the referent group.

Results

Overall, 10% (93) of the 946 women developed breast cancer during the follow-up period. Age-adjusted ORs and 95% confidence intervals (C.I.) compared to non-yielders were 1.4 (0.3 to 6.4), 1.7 (0.9 to 3.5), and 2.0 (1.1 to 3.6) for women with fluid without epithelial cells, normal epithelial cells and hyperplasia/atypia, respectively. Comparing the presence or absence of epithelial cells in NAF, women with epithelial cells present in NAF were more likely to develop breast cancer than non-yielders or women with fluid without epithelial cells (RR = 1.9, 1.2 to 3.1).

Conclusion

These results support previous findings that 1) women with abnormal epithelial cells in NAF have an increased risk of breast cancer when compared to non-yielders or women with normal epithelial cells in NAF and 2) women with epithelial cells present in NAF have an increased risk of breast cancer when compared to non-yielders or women who had NAF without epithelial cells present.

Human breast biomonitoring and environmental chemicals: use of breast tissues and fluids in breast cancer etiologic research

Extensive research indicates that the etiology of breast cancer is complex and multifactorial and may include environmental risk factors. Breast cancer etiology and exposure to xenobiotic compounds, diet, electromagnetic fields, and lifestyle have been the subject of numerous scientific inquiries, but research has yielded inconsistent results. Biomonitoring has been used to explore associations between breast cancer and levels of environmental chemicals in the breast. Research using breast tissues and fluids to cast light on the etiology of breast cancer is, for the most part, predicated on the assumption that the tissue or fluid samples either contain measurable traces of the environmental agent(s) associated with the cancer or that they retain biological changes that are biomarkers of such exposure or precursors of carcinogenic effect. In this paper, we review breast cancer etiology research utilizing breast biomonitoring. We first provide a brief synopsis of the current state of understanding of associations between exposure to environmental chemicals and breast cancer etiology. We then describe the published breast cancer research on tissues and fluids, which have been used for biomonitoring, specifically human milk and its components, malignant and benign breast tissue, nipple aspirate fluid (NAF) and breast cyst fluid. We conclude with a discussion on recommendations for biomonitoring of breast tissues and fluids in future breast cancer etiology research. Both human milk and NAF fluids, and the cells contained therein, hold promise for future biomonitoring research into breast cancer etiology, but must be conducted with carefully delineated hypotheses and a scientifically supportable epidemiological approach.

Proteomics analysis of conditioned media from three breast cancer cell lines: a mine for biomarkers and therapeutic targets

A "bottom-up" proteomics approach and a two-dimensional (strong cation exchange followed by reversed-phase) LC-MS/MS strategy on a linear ion trap (LTQ) were utilized to identify and compare expressions of extracellular and membrane-bound proteins in the conditioned media of three breast cell lines (MCF-10A, BT474, and MDA-MB-468). Proteomics analysis of the media identified in excess of 600, 500, and 700 proteins in MCF-10A, BT474, and MDA-MB-468, respectively. We successfully identified the internal control proteins, kallikreins 5, 6, and 10 (ranging in concentration from 2 to 50 microg/liter) in MDA-MB-468 conditioned medium as validated by ELISA and confidently identified Her-2/neu in BT474 cells. Subcellular localization was determined based on Genome Ontology terms for all the 1,139 proteins of which 34% were classified as extracellular and membrane-bound. Proteomics analysis of MDA-MB-468 cell lysate demonstrated that only 5% of all identified proteins were extracellular. This confirmed our hypothesis that examining the CM of cell lines, as opposed to the cell lysates, leads to a significant enrichment in secreted proteins. Tissue specificity, functional classifications, and spectral counting were performed. Elafin, a protease inhibitor, identified in the conditioned media of BT474 and MDA-MB-468 and the three kallikreins (KLK5, KLK6, and KLK10) were validated using an immunoassay on various serum and biological samples. Some of the secreted proteins identified have established roles in breast cancer development (cell growth, differentiation, and metastasis) and/or are linked to early onset breast cancer. Our approach to mining for low abundance molecules could identify proteins in various stages of breast cancer development. Many of the identified proteins are potentially useful to investigate as circulating serum breast cancer biomarkers.

Effects of High Fruit-Vegetable and/or Low-Fat Intervention on Breast Nipple Aspirate Fluid Micronutrient Levels

BACKGROUND

A change in diet is known to affect micronutrient levels in blood but to what extent diet can affect micronutrient levels in the breast is not yet well established.

METHODS

Healthy, premenopausal women with a family history of breast cancer were randomized across four diet arms for 1 year in a 2 x 2 factorial design study: control, low-fat, high fruit-vegetable, and combination low-fat/high fruit-vegetable diets. Subjects were asked to collect breast nipple aspirate fluid (NAF) at 0, 6, and 12 months, and levels of micronutrients were measured in the fluid.

RESULTS

A total of 122 women were enrolled, 97 were retained for 12 months, and sufficient NAF for analysis was available from 59 women at baseline, 49 at 6 months, and 50 at 12 months. Repeated measures mixed-model ANOVA was used to model the data using cholesterol levels and lactation duration as covariates, where appropriate. The high fruit-vegetable intervention, regardless of fat intake, significantly increased total carotenoid levels in NAF. In the low-fat arm, levels of total carotenoids decreased over time relative to control. Levels of total tocopherols and retinol did not change significantly. Levels of 15-F(2t)-isoprostane, a marker of lipid peroxidation, also did not change significantly over time, although there was a decrease observed in the combination arm.

CONCLUSIONS

These results indicate that total carotenoid levels in NAF can be significantly increased in the breast NAF with a high fruit-vegetable diet. A low-fat diet that was achieved with little increase in fruit and vegetable intake, however, decreased NAF carotenoid levels.

Patient variables that predict atypical cytology by nipple duct lavage

BACKGROUND

Nipple duct lavage (NDL) may be useful for breast cancer risk stratification. Published guidelines recommend that women with a 5-year Gail risk >/=1.7% should consider undergoing lavage for any fluid-yielding ducts, but it is not known whether increased breast cancer risk or nipple fluid production predict lavage atypia.

METHODS

One hundred fifty women unselected for breast cancer risk underwent NDL with cannulation of all nipple aspirate fluid (NAF)-producing ducts and at least 1 dry duct. This resulted in 516 lavage samples. The rate of cytologic atypia was compared for NAF-positive ducts and NAF-negative ducts and for women with 5-year Gail risks >/=1.7% and <1.7%. Ducts from breasts with cancer (N = 113) were excluded from the analysis.

RESULTS

The cytologic atypia rate was similar for the 240 NAF-producing ducts (19%) and the 163 dry ducts (15%; P = .36). No significant differences were observed when atypia was categorized as mild (13% vs 10%; P = .63) or marked (6% vs 4%; P = .53). Among the 83 patients who were unaffected by breast cancer, atypia was diagnosed in 15 of 44 patients (34%) with a 5-year Gail risk <1.7% and in 11 of 39 patients (28%) with a 5-year Gail risk >/=1.7% (P = .74).

CONCLUSIONS

Neither NAF production nor 5-year Gail risk predicted lavage atypia. Limiting NDL to fluid-producing ducts in women with a 5-year Gail risk >/=1.7% significantly reduced the sensitivity of the test for population screening.

A descriptive study of variables associated with obtaining nipple aspirate fluid in a cohort of non-lactating women

BACKGROUND

The search for biologic endpoints and biomarkers in the study of breast cancer risk assessment and risk reduction strategies has led to an interest in obtaining cytologic information and other biomarkers from nipple aspirate fluid (NAF).

METHODS

This descriptive study examined factors associated with an increased ability to obtain NAF in a cohort of 3043 women between the ages of 15 and 89 years of age. The majority of women were between the ages of 30-49 (N = 1529/50.2%). Variables examined in relation to obtaining fluid include: age, marital status, age at menarche, menopausal status, a history of pregnancy, a history of breast-feeding, estrogen use, oral contraceptive use, endocrine disorders and tranquilizer use.

RESULTS

On average, women from whom breast fluid was obtained were younger than women from whom breast fluid was attempted but not obtained (mean = 41.9 years versus 46.5 years, p < 0.0001). In unadjusted and age-adjusted comparisons, being married, a history of pregnancy, younger age at menarche (12 years of age or younger), tranquilizer use, oral contraceptive pill (OCP) use and endocrine problems were associated with an increased ability to obtain breast fluid. Post-menopausal status and exogenous estrogen use were associated with a decreased ability to obtain breast fluid. After age-adjustment, oral contraceptive use was no longer significantly associated with an increased ability to obtain fluid and post-menopausal status was no longer associated with a decreased ability to obtain breast fluid. After multivariate adjustment, age, being married, a history of pregnancy, tranquilizer use and a history of endocrine problems remained positively associated with the ability to obtain breast fluid. In addition, menopausal women who took estrogen were less likely to yield fluid than premenopausal women.

CONCLUSION

Four variables (being married, history of pregnancy, tranquilizer use and endocrine disorders) remained positively associated with the ability to obtain NAF in all analyses. A younger age was consistently associated with a greater ability to obtain NAF in this and other studies.

A strong association between body fat mass and protein profiles in nipple aspirate fluid of healthy premenopausal non-lactating women

Fluid can be aspirated from the nipples of most non-lactating women. This nipple aspirate fluid (NAF) is a potential source for the discovery of new breast cancer biomarkers. NAF has two distinct protein profiles. Type I NAF is similar to the fluid associated with cystic disease of the breast, whereas type II NAF is enriched in milk-associated proteins. The prevalence of these two profiles differs in healthy women and in breast cancer patients. This study investigated the relationship of these two NAF profiles to reproductive history, body composition, diet, and levels of lipids, steroids and thyroid hormones in healthy premenopausal women (age 30-40 years) who had regular menstrual cycles and normal mammograms and were not taking contraceptive medications. On average, women with the type I NAF profile were older, had more years since last childbirth, were less likely to have breastfed their babies and had higher dietary saturated fat intake, body mass index, body fat mass, and levels of plasma low density lipoproteins than women with the type II profile (P <0.05). Using multiple logistic regression, type I NAF was predicted independently (P <0.05) by higher body fat mass [Odds Ratio (OR) = 3.0; 95% Confidence Interval (CI): 1.5-6.1], more years since last childbirth (OR = 2.6; 95% CI: 1.3-5.2) and a higher percentage of calories from saturated fat (OR = 4.1; 95% CI: 1.1-14.6). These results suggest that protein profiles of NAF might be influenced by amounts or types of dietary and body fat, but further study of the relationship of the two profiles to breast cancer risk is needed.

The intraductal approach to breast cancer biomarker discovery

Established methods of breast cancer detection have well-described limitations, and new diagnostic techniques are evolving continually to improve diagnostic accuracy. The intraductal approach encompasses the modalities of nipple aspiration, ductal lavage, and duct endoscopy, and is a means of directly accessing the microenvironment of the breast and either sampling or visualizing this intraductal milieu. The aim of sampling this mammary microenvironment is to obtain samples from the physical surroundings of cells that are undergoing malignant transformation, thereby providing a new method of detection before the development of a clinically or radiologically discernible mass. A literature review was conducted to investigate the evolution of the intraductal approach and its particular application in the field of biomarker discovery, primarily using the intraductal technique of nipple aspiration, in combination with emerging protein profiling techniques.

Ductal lavage of fluid-yielding and non-fluid-yielding ducts in BRCA1 and BRCA2 mutation carriers and other women at high inherited breast cancer risk

OBJECTIVE

Nipple fluid production and atypical breast duct cells in women at high risk of breast cancer have been associated with further increased risk. Most publications on ductal lavage for cell collection report cannulating fluid-yielding ducts only. We report lavage of fluid-yielding and non-fluid-yielding ducts in women at high inherited breast cancer risk.

METHODS

A pilot breast cancer screening study including ductal lavage was conducted in 75 women at high inherited risk, 56 (74.7%) of whom had BRCA1/2 mutations. Ductal lavage was attempted in any duct identifiable with a catheter.

RESULTS

Ducts were successfully catheterized in 60 of 75 patients (80%). Successfully catheterized patients were younger (median age 41 versus 53 years, P = 0.0003) and more often premenopausal (51.7% versus 20%, P = 0.041). Thirty-one successfully catheterized patients [51.6%, 95% confidence interval (39.4-63.9%)] had non-fluid-yielding ducts only. Seventeen patients [28.3% (18.5-40.9%)] had atypical cells. Twelve of seventeen [70.6% (46.8-87.2%)] samples with atypia were from non-fluid-yielding ducts. Patients with non-fluid-yielding ducts (versus fluid-yielding ducts) were more likely to have had prior cancer (48.4% versus 17.2%, P = 0.014) or chemotherapy (45.2% versus 17.2%, P = 0.027); this was also true in patients with atypia from non-fluid-yielding ducts.

CONCLUSION

Successfully lavaged women were younger and more often premenopausal. Atypical cells can be found in non-fluid-yielding ducts in patients at high inherited breast cancer risk. Non-fluid-yielding ducts, and atypia from non-fluid-yielding ducts, are more common in patients with prior cancer and chemotherapy. Larger studies are needed to identify risk factors and prognostic significance associated with atypia and non-fluid-yielding ducts in high-risk populations, and define their role as biomarkers.

Comparison of cytomorphology in specimens obtained by random periareolar fine needle aspiration and ductal lavage from women at high risk for development of breast cancer

Ductal lavage (DL) and random periareolar fine needle aspiration (RPFNA) are both being used to harvest epithelial cells for risk assessment as well as response evaluation in chemoprevention trials. The magnitude of increase in relative risk has been defined in a prospective study for RPFNA but not for DL atypia. We attempted both procedures in 26 women at high risk for development of breast cancer. Median age was 43 (range 32-57); 15 women were premenopausal, with 6 of the postmenopausal women on HRT. Collection of nipple aspirate fluid (NAF) was attempted and, if successful, was followed by DL; RPFNA was then performed on all women. Both procedures were attempted the same day (follicular phase of menstrual cycle if premenopausal) in 24 subjects and within three months for two subjects. Twenty-three subjects produced NAF, 17 of the 23 (74%) had a successful duct cannulation as part of the DL procedure, with 16 yielding sufficient (10) ductal cells for morphologic assessment. Twenty-five of 26 (96%) subjects had a successful RPFNA procedure with adequate cellularity for morphology. There was concordance between DL and RPFNA specimens for traditional cytologic category assessment in 10/16 (63%), Masood index score in 13/16 (82%), and Consensus Panel assessment in 12/16 (75%) of specimens. We conclude that same day DL and RPFNA is feasible, with 62% and 96% of high-risk women having a successful procedure with evaluable cytomorphology. RPFNA was more likely to yield an evaluable specimen, but if a cellular DL specimen was obtained, morphology was generally similar.

Nipple Fluid Cytology

With increasing emphasis on public awareness of breast cancer and screening mammography, more women seek consultation for breast symptoms, including nipple discharge. The presence of nipple discharge is distressing for the patient; however, its origin is fortunately most often benign. Nipple discharge associated with a recognizable mass requires sampling and surgical excision. Currently, clinical breast examination, cytology, ductography, mammogram, and ultrasound are commonly used to evaluate patients who have nipple discharge. Ductal lavage and ductoscopy, in association with emerging new technology, may be of help in increasing the sensitivity of nipple fluid cytology. In addition, nipple fluid cytology may offer a new way to study the spectrum of premalignant breast lesions, and to identify women at risk for breast cancer.

Nutritional predictors for cellular nipple aspirate fluid: Nutrition and Breast Health Study

The presence of epithelial cells in breast nipple aspirate fluid (NAF), irrespective of abnormality, has been associated with increased risk of breast cancer in previous studies. We sought to investigate whether the presence of epithelial cells in NAF is associated with nutritional parameters among 71 healthy premenopausal women who participated in the Nutrition and Breast Health Study and provided any samples of NAF during the study. Total of 142 samples which were obtained over a 1-year period of intervention with low-fat and/or high vegetable-fruit diets were available for cytological evaluation. The odds ratios (ORs) and 95% confidence intervals (CIs) for the detection of epithelial cells in NAF were estimated by fitting generalized estimating equations models by quartile level of nutritional parameters. The probability of yielding epithelial cell-positive NAF progressively increased with increasing total fat intake (p=0.001). The OR for the highest quartile level of fat intake, compared with lowest, was 7.22 (95% CI 1.14-45.82). On the other hand, there were a marginally significant inverse association with total fiber intake as well as an weak inverse association with the number of servings of fruit and vegetables. Furthermore, the probability of detecting epithelial cells in NAF decreased with increasing plasma levels of lutein and alpha-carotene (p-values for linear trend; 0.001 and 0.049, respectively). The ORs for the highest versus lowest quartile levels are 0.17 (95% CI 0.04-0.65) and 0.19 (95% CI 0.04-0.91), respectively. These results are generally in support of roles of nutritional factors in breast cancer and thus further studies are warranted.

Patterns of reduced nipple aspirate fluid production and ductal lavage cellularity in women at high risk for breast cancer

INTRODUCTION

Nipple aspiration is a noninvasive technique for obtaining breast fluids from the duct openings of the nipple for the evaluation of abnormalities associated with breast cancer. Nipple aspirate fluid (NAF) can be elicited from 48 to 94% of healthy women, and its production has been linked to an increased relative risk for breast cancer development. NAF production has been used in studies to guide the selection of ducts for ductal lavage, a procedure in which ducts are cannulated and flushed with saline to collect cells. In a previous multicenter trial to evaluate intraductal approaches in women at high-risk for breast cancer, NAF production was observed in 84% of the subjects. However, we observed a significantly lower proportion of fluid-yielding subjects in a similar series of high-risk women. The purpose of the present study was to identify variables associated with this reduction.

METHOD

Nipple aspiration was performed on 33 high-risk women (defined as having a 5-year Gail model index of more than 1.7, a personal or family history of breast cancer, and/or a BRCA1 or BRCA2 germline mutation) to identify ductal orifices for lavage procedures. Lavage was performed on all fluid-yielding ducts and on nine non-fluid-yielding ducts.

RESULTS

Fluid-yielding ducts were identified in 12 of 33 (36%) of the subjects in the present series, compared with 16 of 19 (84%) of the subjects undergoing identical procedures at our facility during a multicenter trial (P = 0.001). Reduced NAF yields were associated with postmenopausal status (P = 0.02), BRCA germline mutations (P = 0.004), and risk reduction therapies, including bilateral salpingo-oophorectomy (BSO) and/or selective estrogen receptor modulators (SERMs; P = 0.009). All nine (100%) of the ductal lavage specimens collected from non-fluidyielding ducts were acellular, in comparison with 3 of 13 specimens from fluid-yielding ducts (P < .001).

CONCLUSION

Analysis of high-risk women in the present series revealed patterns of reduced NAF production and ductal lavage cellularity compared with a previous multicenter trial. The present series included more BRCA-positive women, many of whom had undergone BSO and/or were using SERMs. Our data suggest that endocrine mechanisms associated with these risk-reducing therapies may be related to patterns of diminished breast fluid production.

Cytologic features of nipple aspirate fluid using an automated non-invasive collection device: a prospective observational study

Background

Detection of cytologic atypia in nipple aspirate fluid (NAF) has been shown to be a predictor of risk for development of breast carcinoma. Manual collection of NAF for cytologic evaluation varies widely in terms of efficacy, ease of use, and patient acceptance. We investigated a new automated device for the non-invasive collection of NAF in the office setting.

Methods

A multi-center prospective observational clinical trial involving asymptomatic women designed to assess fluid production, adequacy, safety and patient acceptance of the HALO NAF Collection System (NeoMatrix, Irvine, CA). Cytologic evaluation of all NAF samples was performed using previously described classification categories.

Results

500 healthy women were successfully enrolled. Thirty-eight percent (190/500) produced fluid and 187 were available for cytologic analysis. Cytologic classification of fluid producers showed 50% (93/187) Category 0 (insufficient cellular material), 38% (71/187) Category I (benign non-hyperplastic ductal epithelial cells), 10% (18/187) Category II (benign hyperplastic ductal epithelial cells), 3% (5/187) Category III (atypical ductal epithelial cells) and none were Category IV (unequivocal malignancy). Overall, 19% of the subjects produced NAF with adequate cellularity and 1% were found to have cytologic atypia.

Conclusion

The HALO system is a simple, safe, rapid, automated method for standardized collection of NAF which is acceptable to patients. Cytologic assessment of HALO-collected NAF showed the ability to detect benign and pre-neoplastic ductal epithelial cells from asymptomatic volunteers.

Influence of Lactation History on Breast Nipple Aspirate Fluid Yields and Fluid Composition

Analysis of nipple aspirate fluid (NAF) can be useful for understanding the impact that various lifestyle factors have on the biology of the breast. In this study, breast NAF was obtained at baseline from premenopausal women who volunteered for a dietary intervention trial. The influence of lactation history on both fluid yields and fluid composition was explored. We examined the levels of fat-soluble micronutrients (tocopherols, carotenoids, retinol), one lipid oxidation product (8-isoprostane), cholesterol, and protein in NAF. Roughly half of the women in the trial had never lactated, but this did not affect fluid yields appreciably. Carotenoid and tocopherol levels were significantly higher in NAF from women who lactated 6 months or more versus women who had lactated for shorter periods of time or never, but 8-isoprostane, protein, and cholesterol levels were not affected appreciably by lifetime lactation history. Longer times after weaning were associated with higher cholesterol levels, and there also was a suggestion the fat-soluble micronutrients declined with time after weaning. This is of interest since high cholesterol levels in breast fluid have been associated with an increased breast cancer risk, while carotenoids and tocopherols are thought to be protective. The results of this study provide further evidence of the potential benefits of prolonged lactation via its influence on NAF composition.

Failure of high risk women to produce nipple aspirate fluid does not exclude detection of cytologic atypia in random periareolar fine needle aspiration specimens

INTRODUCTION

Evidence of hyperplasia with atypia found both on random periareolar fine needle aspiration (RPFNA) and in nipple aspirate fluid (NAF) fluid are associated with an increased risk for breast cancer.

AIM

In this study, we report the correlation of NAF production with cytological assessment of ductal cells obtained by RPFNA.

METHODS

113 women at high risk for development of breast cancer attending the Breast Cancer Prevention Clinic at the University of Kansas Medical Center underwent a single NAF collection attempt and RPFNA.

RESULTS

NAF was successfully collected in 51% of women. There was no significant difference in age, 5-year Gail risk assessment, menopausal status, hormone use, family history of breast cancer, history of prior atypical hyperplasia/LCIS or history of contralateral DCIS/invasive breast cancer between women who produced NAF and those that did not. The only significant difference between the two groups was in history of prior lactation (p = 0.018). Twenty-seven of the 113 subjects were found to have hyperplasia with atypia by RPFNA was 31% in women who produced NAF versus 16% in those who did not (p = 0.07).

CONCLUSION

Although prevalence of RPFNA atypia was numerically higher in NAF producers than non-producers the difference did not reach statistical significance. Failure to produce NAF does not exclude the presence of hyperplasia with atypia by random periareolar fine needle aspiration.

Ductal approaches to assessment and management of women at high risk for developing breast cancer

The ductal approach to breast cancer, encompassing nipple aspiration, ductal lavage and duct endoscopy, allows assessment of breast ductal epithelial cells and their local microenvironment in a graded process of increasing invasiveness. Samples of ductal epithelial cells sufficient for cytological diagnosis may be safely collected, titres of individual proteins showing variation with breast cancer status may be measured, and abnormal pathology within the breast ducts may be directly visualized. Identification of surrogate molecular markers may facilitate early breast cancer detection, in conjunction with cytological assessment, and be useful for individual prediction of breast cancer risk and assessment of treatment response. However, the sensitivity and specificity of the ductal approach require further evaluation. The small quantities of nipple aspiration fluid available for analysis, and difficulties identifying and cannulating ducts remain important limitations of these techniques.

Nipple aspirate fluid in relation to breast cancer

Samples of breast ductal fluid can be obtained by nipple aspiration. Such samples may contain a variety of exfoliated or shed cells and display a distinctive biochemical profile reflecting the microenvironment of the ductal-alveolar system of the breast. Study of nipple aspirates may, therefore, shed light on the biology of breast cancer. This review summarizes the more important aspects of published data and explores potential avenues for future study with particular regard to molecular-biological approaches.

Ductal lavage and its histopathologic basis: A cautionary tale

Ductal lavage has been touted as a possible screening tool for patients with a high risk for the development of breast cancer. This article examines the fundamental concepts underlying the procedure and critically evaluates its possible utility in light of the known molecular and surgical pathologic data. It highlights the fact that risk assessment in breast cancer is far from an exact science, since most women who develop breast cancers are not identified as high-risk by the Gail model. The utility of ductal lavage has as yet not been proven, and even if it were useful, it is likely to benefit only a subset of all breast cancer patients. Further studies, preferably controlled clinical trials, are necessary before routine use of the procedure can be recommended.

The use of oxytocin in nipple fluid aspiration

It has been shown that early detection of breast cancer saves lives. Recently there has been increasing interest in nipple aspirate fluid as a potential avenue for breast cancer diagnosis. One major challenge regarding studies of nipple aspirate fluid is the ability to obtain adequate samples. Here we describe the use of nasal oxytocin in a group of volunteer women in order to increase the yield of nipple aspirate fluid.

Proteomic characterization of nipple aspirate fluid: identification of potential biomarkers of breast cancer

Mammary ductal cells are the origin for 70-80% of breast cancers. Nipple aspirate fluid (NAF) contains proteins directly secreted by the ductal and lobular epithelium in non-lactating women. Proteomic approaches offer a largely unbiased way to evaluate NAF as a source of biomarkers and are sufficiently sensitive for analysis of small NAF volumes (10-50 microl). In this study, we initially evaluated a new process for obtaining NAF and discovered that this process resulted in a volume of NAF that was suitable for analysis in approximately 90% of subjects. Proteomic characterization of NAF identified 64 proteins. Although this list primarily includes abundant and moderately abundant NAF proteins, very few of these proteins have previously been reported in NAF. At least 15 of the NAF proteins identified have previously been reported to be altered in serum or tumor tissue from women with breast cancer, including cathepsin D and osteopontin. In summary, this study provides the first characterization of the NAF proteome and identifies several candidate proteins for future studies on breast cancer markers in NAF.

Nipple aspirate fluid cytology in breast carcinoma

BACKGROUND

Nipple aspirate fluid (NAF) cytology is a simple noninvasive method to study cells exfoliated into the ductal system of the breast. In the current study, the significance of cytologic findings in NAF was determined by correlating them with histopathologic findings from corresponding breast tissue. Cytologic-histologic correlations of NAF were performed in only a few studies.

METHODS

Nipple aspirate fluid was collected by breast massaging and by using a breast aspiration device from 74 women with biopsy confirmed intraductal or invasive carcinoma with or without a history of preoperative neoadjuvant chemotherapy. Cytospin preparations were Pap stained. The number of epithelial cells was quantitated and foamy macrophages were semiquantitatively scored. Cytologic findings were categorized as insufficient for diagnosis (less than 10 epithelial cells), benign, mild atypia, marked atypia or suspicious, and malignant. Finally, they were correlated with tissue findings.

RESULTS

Nipple aspirate fluid was obtained from 74 women, including 24 who had received preoperative neoadjuvant chemotherapy. The median age of patients was 54 years. A mean volume of 57 microL NAF and a mean of 149 epithelial cells were obtained. Foamy macrophages were present in 51 (70%) of the specimens. There was a significant correlation between the presence of epithelial cells and foamy macrophages (P < 0.001). Patients treated with chemotherapy had fewer epithelial cells in their NAF compared with patients who were not treated with chemotherapy. Thirty specimens (41%) were inadequate for diagnosis, 34 were (46%) benign, 5 (7%) were mildly atypical, 1 (1%) was markedly atypical, and 4 (5%) were malignant. Of the five cases with mildly atypical cytology, three were intraductal papilloma, one was low-grade papillary intraductal carcinoma, and one was low-grade intracystic papillary carcinoma with invasion in the corresponding tissue specimen. The single case with markedly atypical NAF cytology had extensive ductal carcinoma in situ (DCIS). Of the four cases with malignant NAF cytology, two were extensive DCIS and two had invasive carcinoma with extensive DCIS in the breast specimen. Overall, 3 (27%) of 11 cases of DCIS were detected in NAF and only 2 (4%) of 52 invasive carcinomas including the only two cases with extensive DCIS were detected in NAF.

CONCLUSION

The probability of detecting malignant cells in NAF is dependent on the extent of DCIS and nipple involvement by DCIS. Nipple aspirate fluid is not a sensitive test for detecting invasive carcinoma of the breast. Atypical cytology in NAF is associated with papillary lesions in the underlying breast.

Presence of carotenoid, an anticarcinogenic marker, in nipple aspirates postlactation

Case-controlled studies have identified a protective effect of lactation against breast cancer; however, little is known about the nature of this protective mechanism. The purpose of this study was to examine postweaned, nipple aspirate fluid (NAF) from women, ages 18 to 45, for carotenoid, a known antioxidant and anticarcinogenic marker, and compare carotenoid availability in NAF with that reported in colostrum. Women who had lactated at least 6 months and weaned for at least 6 months were recruited into the study A prestudy and poststudy serum prolactin level was obtained. NAF was obtained through a nipple aspirator method. Total carotenoid ranged from 0.4 to 4.0 microg/mL, with a mean level of 1.9+/-1.2 (SD). Women who had weaned earlier (<12mo) had significantly more carotenoids than those who had lactated longer (>12mo) (P = 0.04). These levels were similar to those known to occur in colostrum. This research elucidates possible mechanisms of the protective effect of lactation on the microenvironment of the breast.

Breast cancer risk in women with abnormal cytology in nipple aspirates of breast fluid

BACKGROUND

We previously showed that women with abnormal cytology in breast fluid obtained by nipple aspiration had an increased relative risk (RR) of breast cancer compared with women from whom fluid was not obtained and with women whose fluid had normal cytology. This study extends the follow-up in the original study group (n = 4046) and presents the first follow-up for a second group of women (n = 3627).

METHODS

We collected nipple aspirate fluid from women in the San Francisco Bay Area during the period from 1972 through 1991, classified the women according to the most severe epithelial cytology observed in fluid specimens, and determined breast cancer incidence through March 1999. We estimated RRs for breast cancer using Cox regressions, adjusting for age and year of study entry. All statistical tests were two-sided.

RESULTS

For women in the first and second study groups, the median years of follow-up were 21 years and 9 years, respectively, and breast cancer incidences were 7.8% (285 cases in the 3633 women for whom breast cancer status could be determined) and 3.5% (115 of 3271), respectively. Compared with women from whom no fluid was obtained, whose incidences of breast cancer were 4.7% (39 of 825) and 3.3% (65 of 1950) for those in group 1 and group 2, respectively, incidences and adjusted RRs were 8.1% (34 of 422), with RR = 1.4 (95% confidence interval [CI] = 0.9 to 2.3), and 0% (0 of 31), respectively, for those with unsatisfactory aspirate specimens and 8.2% (148 of 1816), with RR = 1.6 (95% CI = 1.1 to 2.3), and 3.1% (25 of 811), with RR = 1.2 (95% CI = 0.8 to 2.0), respectively, for those with normal cytology in aspirates. Compared with women from whom no fluid was obtained, incidences and adjusted RRs for women in group 1 with epithelial hyperplasia and atypical hyperplasia in aspirates were 10.8% (52 of 483), with RR = 2.4 (95% CI = 1.6 to 3.7), and 13.8% (12 of 87), with RR = 2.8 (95% CI = 1.5 to 5.5), respectively, while those for women in group 2 were 5.5% (25 of 457) and 0% (0 of 22), respectively, with a combined RR = 2.0 (95% CI = 1.3 to 3.3).

CONCLUSION

The results obtained with the newly followed women independently confirmed previous findings that women with abnormal cytology in nipple aspirates of breast fluid have an increased risk of breast cancer.

Nipple aspiration in diagnosis of breast cancer

It has been shown that early detection of breast cancer saves lives. Mammography and physical examination are currently the most commonly utilized screening methods for breast cancer. Research is being carried out to optimize these screening methods, as well as to develop new techniques. This review summarizes the findings of the research focusing on the diagnostic techniques involving the breast ductal system to date. These tests include nipple fluid cytology, nipple fluid tumor markers, ductogram, and ductoscopy.

Nipple fluid carcinoembryonic antigen and prostate-specific antigen in cancer-bearing and tumor-free breasts

PURPOSE

Mammograms and breast examinations are established methods for early breast cancer detection. Routine mammography screening reduces breast cancer mortality among women ages > or = 50 years, but additional screening methods are needed. We and others have found high levels of carcinoembryonic antigen (CEA) and prostate-specific antigen (PSA) in nipple aspirate fluids (NAFs), but the usefulness for these bio-markers for early breast cancer detection is unknown.

PATIENTS AND METHODS

NAFs from one or both breasts of 388 women were analyzed for CEA, PSA, and albumin levels. The study included 44 women with newly diagnosed invasive breast cancers, 67 women with proliferative breast lesions (ductal and lobular carcinoma in situ and atypical ductal hyperplasia), and 277 controls without these breast lesions. Analyses were conducted using the log(10)-transformed CEA and PSA levels to normalize the distributions of these tumor markers.

RESULTS

Nipple fluid CEAs are significantly higher for cancerous breasts than tumor-free breasts (median 1,830 and 1,400 ng/mL, respectively; P <.01). However, at 90% specificity of the assay (CEA = 11,750 ng/mL), the corresponding sensitivity for cancer detection is 32%. CEA levels are not significantly different for breasts with proliferative lesions compared with tumor-free breasts. Nipple fluid PSAs do not differ by tumor status. Analyses of NAF albumin-standardized CEAs and PSAs yield similar results. Nipple fluid CEA and PSA titers are correlated in the affected and unaffected breast of women with unilateral lesions.

CONCLUSION

Nipple fluid CEAs are higher for breasts with untreated invasive cancers, but the test sensitivity is low. Nipple fluid PSA titers do not seem to be useful for breast cancer detection.

Hormonally-regulated proteins in breast secretions are markers of target organ sensitivity

Anti-oestrogen therapy is being used in an attempt to prevent breast cancer but no intermediate end points of the effect of tamoxifen on the normal breast are available. Therefore, the purpose of this study was to develop a physiological measure of oestrogen action on the breast. We measured oestrogen-stimulated and -inhibited proteins in breast secretions from women on and off anti-oestrogen therapy. Two oestrogen-stimulated proteins (pS2 and cathepsin D) and oestrogen-inhibited proteins (CP15, gross cystic disease fluid protein 15; Apo,: apolipoprotein D) were measured. Premenopausal women had significantly higher pS2 and cathepsin D in association with lower Apo D and CP15 secretion levels compared to post-menopausal women. Sequential nipple aspirates from women treated with the luteinizing hormone releasing hormone agonist goserelin (n = 9), tamoxifen (n = 9) and hormone replacement therapy (HRT) (n = 26) were measured. Following treatment with goserelin, median nipple secretion levels of pS2 fell (P < 0.02) and Apo D and CP15 rose significantly (P < 0.03 and P < 0.05 respectively). Similar changes were seen on tamoxifen therapy but not in untreated control women. Treatment with HRT resulted in a rise of pS2 (P < 0.001) and a fall in Apo D (P < 0.05). Measurement of pS2 and Apo D in nipple aspirates may prove useful intermediate end point of breast responsiveness to anti-oestrogens.

Nipple aspirate fluid: a promising non-invasive method to identify cellular markers of breast cancer risk

To evaluate the feasibility of nipple aspiration and to identify intermediate markers of breast cancer risk, nipple aspirate fluid (NAF) was collected from 177 subjects using a modified breast pump. The first 33 subjects demonstrated that we could obtain NAF quickly, reliably and repeatedly. Specimens from the remaining 144 subjects were collected to evaluate promising cellular biomarkers. NAF was obtained in 167 out of 177 (94%) subjects overall and in 99% of the 144 most recent subjects. Sufficient NAF was obtained to evaluate cytology in 160 out of 167 (96%) cases and specimens were sufficiently cellular to analyse DNA markers in 53% of cases. Among the last 144 subjects, menopausal status did not influence the ability to obtain NAF. NAF cytology correlated with increased breast cancer risk (P = 0.002). Using computerized image analysis of NAF epithelial cells, DNA index (P = 0.0002), percentage of cells in G2M (P = 0.05) and percentage of cells with hypertetraploidy (P = 0.002) increased as cytology became more abnormal. Our data indicate that NAF can be obtained in essentially all eligible subjects; that breast epithelial cells are evaluable in > 95% of NAF samples for cytology and in over half of NAF samples for DNA index (ploidy) and cell cycle analysis; and that abnormal NAF cytology correlates with increased breast cancer risk. This suggests that biomarkers identified in nipple aspirate fluid may prove useful either as an adjunct to currently accepted breast cancer screening methods, or to evaluate response to a chemopreventive agent.