Prostate-specific antigen in nipple aspiration fluid: menstrual cycle variability and correlation with serum prostate-specific antigen

Analysis of nipple aspirate fluid for diagnosis of breast cancer: an alternative to invasive biopsy

Over 40,000 women in the USA will die this year of breast cancer. Current generally accepted techniques to detect breast cancer are limited to breast examination and mammography. Abnormalities found by these techniques require an invasive needle or surgical biopsy to determine if cancer is present. The author's ultimate goal is to determine if a woman has breast cancer without the need for invasive biopsies, and do this before the abnormality is detectable by standard screening techniques. Herein, the technology is reviewed as it was, as it is today, and its future potential is discussed.

Intracrinology of breast microenvironment: hormonal status in nipple aspirate fluid and its relationship to breast cancer

Breast cancer, a complex and multifactorial disease, is the most commonly diagnosed malignancy affecting women. Methods currently available for breast cancer detection have well-described limitations; in this respect, the intraductal approaches directly assess the microenvironment of the breast. Nipple aspirate fluid (NAF) can be noninvasively obtained from the breast in most women and represents a promising biological tool to assess metabolic, hormonal and molecular changes occurring in the cells lining the ducts, from which breast cancer arises. The aim of this review is to highlight the application of NAF studies in the field of biomarker discovery, which provide results useful for early detection and prevention of breast cancer risk; in fact, the analysis of NAF (mirroring the ductal-lobular microenvironment) is a reliable method for assessment of metabolic/hormonal pathways within the mammary gland, identifying biomolecular mechanisms of breast cancer initiation and progression. The intracrinology of breast microenvironment (i.e., hormonal status in NAF) may provide independent diagnostic/prognostic factors, highlighting the importance of early altered hormonal metabolism (e.g., aromatase, estrogen sulfotransferase and steroid sulfatase pathway) in relation to breast cancer initiation. The possible application of targeted therapies through the inhibition of intratumoral enzymes involved in steroid metabolism is also discussed. The intraductal approach to hormone analyses may provide a further panel of biomarkers providing clinical benefits and strengthening the armory against breast cancer.

Clinical validation of breast cancer biomarkers using tissue microarray technology

The results of previous studies done in our laboratory on breast cancer gene expression profile, using DNA microarrays, led to the discovery of several genes associated with breast cancer progression. Further evaluation of these genes and their involvement at various stages of cancer progression required performance of immunohistochemistry on thousands of different tissue blocks. Tissue microarray (TMA) technology facilitates rapid translation of DNA microarrays results to clinical specimens by using immunohistochemical analysis of protein expression. DNA microarray analysis done in our laboratory showed a significantly higher expression of prostatic-specific antigen (PSA) in invasive ductal carcinomas as compared to ductal carcinoma in situ, a finding contrary to the previously published data for PSA immunoreactivity in breast carcinomas. To find out whether TMA strategy could be used to explore the expression of the candidate genes involved in the breast cancer progression, we constructed a breast cancer progression TMA. It consisted of 2 normal ductal epithelium, 8 ductal carcinoma in situ, 19 invasive ductal carcinomas, and 3 metastatic ductal carcinomas of breast in triplets. Two prostatic adenocarcinomas and 2 normal colons were used as positive and negative controls, respectively. We first used well-documented and well-tested markers, such as antibodies to estrogen receptor, progesterone receptor, and p53. Results of these 3 antibodies were according to the previously published data. To validate our result, we then used antibody to PSA and looked for the expression of this protein on breast cancer progression TMA. Except for the 2 positive controls all 98 cores were found to be negative for PSA expression highlighting the importance of validation studies for DNA microarray results.

Proteomic analysis of nipple aspirate fluid throughout the menstrual cycle in healthy pre-menopausal women

A proteomic approach to nipple aspiration fluid (NAF) has been used in a number of studies comparing women with breast cancer and healthy women. However, to make useful comparisons between women with breast cancer and healthy women it is necessary to establish whether there is physiological variation in the proteomic profiles of NAF. The purpose of this study was, for the first time, to examine how the proteomic profile of NAF using surface-enhanced laser desorption ionisation time-of-flight mass spectrometry varies across the menstrual cycle in healthy pre-menopausal women. Twelve women were recruited and nipple aspiration was carried out weekly from both breasts of each subject for two menstrual cycles. Matching serum samples for luteinising hormone, follicle stimulating hormone and oestradiol were obtained at each aspiration attempt. Statistically significant peaks were found for three healthy volunteers (p < 0.05). However, the peaks that varied across the menstrual cycle were different from one healthy volunteer to another and the differences were small compared with the large variation in proteomic profiles between healthy volunteers. This study provides proof of concept that the NAF proteomic profile does not vary substantially during the menstrual cycle and that therefore it is valid to compare NAF profiles from pre-menopausal women that have been taken at different stages in the menstrual cycle.

Serum PSA levels are not affected by the menstrual cycle or the menopause, but are increased in subjects with polycystic ovary syndrome

BACKGROUND/AIMS

Prostatic specific antigen (PSA) is the most specific prostatic tumor marker in man. Recently, PSA has been detected in a variety of tissues and fluids in women, and its determination suggested as a marker of hyperandrogenism. However, precise information about the physiology of PSA in females is not available. The goal of this study was to assess serum concentrations of PSA in healthy pre-menopausal women (healthy pre-menopausal group), menopausal women (menopause group) and patients with polycystic ovary syndrome (PCOS group).

METHODS

PSA, androgens, LH, FSH, 17-beta-estradiol (E2), progesterone (Pg) were assessed in 40 post-menopausal women, 35 fertile controls and 35 women with PCOS.

RESULTS

No significant difference in PSA concentrations could be demonstrated in different phases of the menstrual cycle in healthy pre-menopausal group and between pre- and post-menopausal groups. No correlations could be demonstrated between serum PSA levels and the following parameters: age, body mass index (BMI), LH, FSH, E2, testosterone (T), DHEAS, and SHBG, both in pre- and post-menopausal women. Significantly higher PSA levels (median=14 pg/ml) were found in the PCOS group compared to both pre-menopausal (median=5 pg/ml) and menopausal (median= 5 pg/ml) groups (p< 0.05).

CONCLUSIONS

only minor fluctuations of serum PSA concentrations are observed in healthy pre- and post-menopausal women, while serum level is higher in PCOS, and therefore PSA can be considered a suitable marker of female hyperandrogenism.

Nipple fluid basic fibroblast growth factor in patients with breast cancer

PURPOSE

It has been shown that early detection of breast cancer could save lives. Recently, there has been increasing interest in nipple fluid as a potential supplemental avenue for breast cancer diagnosis.

EXPERIMENTAL DESIGN

In this study, we determined the levels of an angiogenic factor basic fibroblast growth factor (bFGF) in the nipple fluid of healthy subjects as well as patients with benign breast conditions, those at high risk for breast cancer, and patients with active breast cancer. ELISAs were used to measure bFGF.

RESULTS

Nipple fluid bFGF levels were as follows (mean +/- SE): 158 +/- 17 pg/mL from benign breasts, 561 +/- 277 pg/mL from high-risk breasts, and 1,343 +/- 441 pg/mL from cancerous breasts. One-way ANOVA showed that the bFGF levels from cancerous breasts were significantly higher than those from benign and high-risk breasts (P = 0.0001 and P = 0.0193, respectively). After logarithmic transformation was applied to the data, high-risk breast bFGF levels were higher than those from benign breasts (P = 0.0028). With a cutoff level of 250 pg/mL, the sensitivity was 79.2%, specificity was 82.5%, and correct diagnosis was 66.4%. The area under the receiver operating characteristic curve was 0.86.

CONCLUSIONS

We conclude that nipple fluid bFGF levels are progressively elevated in high-risk and cancerous breasts compared with benign breasts. The sensitivity and specificity of this test are promising compared with current breast cancer screening methods, and this test deserves further studies with larger clinical trials. Potential areas of usefulness include the detection of breast cancer risk or breast cancer, as well as the monitoring and/or prediction of the antiangiogenic effect of preventive therapies.

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.