Ductal lavage is an inefficient method of biomarker measurement in high-risk women

Early detection of breast cancer through the diagnosis of Nipple Aspirate Fluid (NAF)

The development of breast cancer has been mainly reported in women who have reached the post-menopausal stage; therefore, it is the primary factor responsible for death amongst postmenopausal women. However, if treated on time it has shown a survival rate of 20 years in about two-thirds of women. Cases of breast cancer have also been reported in younger women and the leading cause in them is their lifestyle pattern or they may be carriers of high penetrance mutated genes. Premenopausal women who have breast cancer have been diagnosed with aggressive build-up of tumors and are therefore at more risk of loss of life. Mammography is an effective way to test for breast cancer in women after menopause but is not so effective for premenopausal women or younger females. Imaging techniques like contrast-enhanced MRI can up to some extent indicate the presence of a tumor but it cannot adequately differentiate between benign and malignant tumors. Although the 'omics' strategies continuing for the last 20 years have been helpful at the molecular level in enabling the characteristics and proper understanding of such tumors over long-term longitudinal monitoring. Classification, diagnosis, and prediction of the outcomes have been made through tissue and serum biomarkers but these also fail to diagnose the disease at an early stage. Considerably there is no adequate detection technique present globally that can help early detection and provide adequate specificity, safety, sensitivity, and convenience for the younger and premenopausal women, thereby it becomes necessary to take early measures and build efficient tools and techniques for the same. Through biopsies of nipple aspirate fluid (NAF) biomarker profiling can be performed. It is a naturally secreted fluid from the cells of epithelium found in the breast. Nowadays, home-based liquid biopsy collection kits are also available through which a routine check on breast health can be performed with the help of NAF. Herein, we will review the biomarker screening liquid biopsy, and the new emerging technologies for the examination of cancer at an early stage, especially in premenopausal women.

Evaluation of nipple aspirate fluid as a diagnostic tool for early detection of breast cancer

There has been tremendous progress in detection of breast cancer in postmenopausal women, resulting in two-thirds of women surviving more than 20 years after treatment. However, breast cancer remains the leading cause of cancer-related deaths in premenopausal women. Breast cancer is increasing in younger women due to changes in life-style as well as those at high risk as carriers of mutations in high-penetrance genes. Premenopausal women with breast cancer are more likely to be diagnosed with aggressive tumours and therefore have a lower survival rate. Mammography plays an important role in detecting breast cancer in postmenopausal women, but is considerably less sensitive in younger women. Imaging techniques, such as contrast-enhanced MRI improve sensitivity, but as with all imaging approaches, cannot differentiate between benign and malignant growths. Hence, current well-established detection methods are falling short of providing adequate safety, convenience, sensitivity and specificity for premenopausal women on a global level, necessitating the exploration of new methods. In order to detect and prevent the disease in high risk women as early as possible, methods that require more frequent monitoring need to be developed. The emergence of "omics" strategies over the last 20 years, enabling the characterisation and understanding of breast cancer at the molecular level, are providing the potential for long term, longitudinal monitoring of the disease. Tissue and serum biomarkers for breast cancer stratification, diagnosis and predictive outcome have emerged, but have not successfully translated into clinical screening for early detection of the disease. The use of breast-specific liquid biopsies, such as nipple aspirate fluid (NAF), a natural secretion produced by breast epithelial cells, can be collected non-invasively for biomarker profiling. As we move towards an age of active surveillance, home-based liquid biopsy collection kits are increasingly being applied and these could provide a paradigm shift where NAF biomarker profiling is used for routine breast health monitoring. The current status of established and newly emerging imaging techniques for early detection of breast cancer and the potential for alternative biomarker screening of liquid biopsies, particularly those applied to high-risk, premenopausal women, will be reviewed.

Examination of Duct Physiology in the Human Mammary Gland

Background

The human breast comprise several ductal systems, or lobes, which contain a small amount of fluid containing cells, hormones, proteins and metabolites. The complex physiology of these ducts is likely a contributing factor to the development of breast cancer, especially given that the vast majority of breast cancers begin in a single lobular unit.

Methods

We examined the levels of total protein, progesterone, estradiol, estrone sulfate, dehydroepiandrosterone sulfate, and macrophages in ductal fluid samples obtained from 3 ducts each in 78 women, sampled twice over a 6 month period. Samples were processed for both cytological and molecular analysis. Intraclass correlation coefficients and mixed models were utilized to identify significant data.

Results

We found that the levels of these ductal fluid components were generally uncorrelated among ducts within a single breast and over time, suggesting that each lobe within the breast has a distinct physiology. However, we also found that estradiol was more correlated in women who were nulliparous or produced nipple aspirate fluid.

Conclusions

Our results provide evidence that the microenvironment of any given lobular unit is unique to that individual unit, findings that may provide clues about the initiation and development of ductal carcinomas.

Breast cancer risk assessment, prevention, and the future

Today breast cancer remains a major public health problem, although reducing its risk is now an achievable medical objective. Risk-assessment models may be used in estimating a woman's risk for developing breast cancer and to direct suitable candidates for preventive therapy. Researchers are attempting to enhance individualized risk assessment through incorporation of phenotypic biomarkers. Individual selective estrogen receptor modulators have been approved for breast cancer risk reduction, and other drug categories are being studied. It is critical that obstetrician-gynecologists be familiar with the evolving science of the risk assessment of breast cancer as well as interventional and surveillance strategies.

Comparison of Random Periareolar Fine Needle Aspirate versus Ductal Lavage for Risk Assessment and Prevention of Breast Cancer

Random periareolar fine needle aspiration (RPFNA) and ductal lavage (DL) are research techniques developed to (1) assess short-term breast cancer risk in asymptomatic women who are at increased risk for breast cancer and (2) track cytological response to risk reduction strategies. RPFNA and DL provide minimally invasive methods to repeatedly sample epithelial cells and research tools to investigate the biological origins of breast cancer in high-risk women. This review gives an overview of the strengths and limitations of both RPFNA and DL for risk assessment and breast cancer prevention in asymptomatic high-risk women.

Does ductal lavage assert its role as a noninvasive diagnostic modality to identify women at low risk of breast cancer development?

Objective

Ductal lavage (DL) involves evaluation of the ductal system of the breast for detection of intra-ductal carcinomas and precursor lesions by collecting breast epithelial cells using a small-gauge catheter inserted into a ductal orifice on the nipple. The aim of this survey was to analyze cytologic features of samples obtained from low-risk women with DL and to elucidate the efficacy of this diagnostic modality in evaluating fluid production, cannulating and determining atypical breast epithelial cells.

Methods

Into this prospective study were consecutively registered 80 women between ages 28 to 67. Nipple aspiration was performed to identify all fluid-yielding ducts. According to the grading of specific features the interpretation of the sample included: normal/benign (category, 0), mild atypical (category, I), markedly atypical (category, II) or malignant (category, III) disorders.

Results

Ninety five percent (316/334) of the nipple aspirate fluid samples were classified as category 0, 4.8% (16/334) as category I and 0.2% (2/334) as category II changes. Category III disorders were not detected. Therefore, in 80% of the women examined results were within normal limits while 17.5% of the participants presented mild atypical and 2.5% markedly atypical rates.

Conclusion

DL collection procedure proved to be rapid as well as acceptable by the women studied. It retains the advantage over other methods of nipple aspirate fluid in that it is easy to perform, thereby removing most clinician variability. It also helped low risk women to discriminate those with breast disorders that require additional investigation, further follow-up or administration of preventive medication.

Soy isoflavone supplementation for breast cancer risk reduction: a randomized phase II trial

Soy isoflavone consumption may protect against breast cancer development. We conducted a phase IIB trial of soy isoflavone supplementation to examine its effect on breast epithelial proliferation and other biomarkers in the healthy high-risk breast. One hundred and twenty-six consented women underwent a random fine-needle aspiration (rFNA); those with 4,000 or more epithelial cells were randomized to a double-blind 6-month intervention of mixed soy isoflavones (PTIG-2535) or placebo, followed by repeat rFNA. Cells were examined for Ki-67 labeling index and atypia. Expression of 28 genes related to proliferation, apoptosis, and estrogenic effect was measured using quantitative reverse transcriptase PCR. Hormone and protein levels were measured in nipple aspirate fluid (NAF). All statistical tests were two-sided. Ninety-eight women were evaluable for Ki-67 labeling index. In 49 treated women, the median Ki-67 labeling index was 1.18 at entry and 1.12 post intervention, whereas in 49 placebo subjects, it was 0.97 and 0.92 (P for between-group change: 0.32). Menopausal stratification yielded similar results between groups, but within premenopausal soy-treated women, Ki-67 labeling index increased from 1.71 to 2.18 (P = 0.04). We saw no treatment effect on cytologic atypia or NAF parameters. There were significant increases in the expression of 14 of 28 genes within the soy, but not the control group, without significant between-group differences. Plasma genistein values showed excellent compliance. A 6-month intervention of mixed soy isoflavones in healthy, high-risk adult Western women did not reduce breast epithelial proliferation, suggesting a lack of efficacy for breast cancer prevention and a possible adverse effect in premenopausal women.

[The role of ductoscopy in the modern diagnostics and therapy of breast diseases]

Mammary ductoscopy is a modern, minimally invasive procedure that enables direct, in vivo observation of the mammary ductal system, primarily by nipple discharge. The rapidly developing device is suitable for aimed biopsy for further cytological or molecular examinations. High-tech equipments facilitate polypectomy or laser vaporization of certain intraluminal lesions, and play an important role in the direct surgical excision of the duct or the so-called terminal duct-lobular unit. The above listed facilitate the early diagnosis of malignancies even before imaging could detect them, and the control of high risk patients. Ductoscopy can foster surgical removal of ductal in situ tumors as anatomical units, thus enabling the optimization of radicality of breast conserving surgeries. Authors give a detailed description of the surgical techniques, and provide a wide review of the literature, for the first time in the Hungarian language. Orv. Hetil., 2011, 152, 1284-1293.

Clinical trial design for testing the stem cell model for the prevention and treatment of cancer

The cancer stem cell model introduces new strategies for the prevention and treatment of cancers. In cancers that appear to follow the stem cell model, pathways such as Wnt, Notch and Hedgehog may be targeted with natural compounds such as curcumin or drugs to reduce the risk of initiation of new tumors. Disease progression of established tumors could also potentially be inhibited by targeting the tumorigenic stem cells alone, rather than aiming to reduce overall tumor size. These new approaches mandate a change in the design of clinical trials and biomarkers chosen for efficacy assessment for preventative, neoadjuvant, adjuvant, and palliative treatments. Cancer treatments could be evaluated by assessing stem cell markers before and after treatment. Targeted stem cell specific treatment of cancers may not result in “complete” or “partial” responses radiologically, as stem cell targeting may not reduce the tumor bulk, but eliminate further tumorigenic potential. These changes are discussed using breast, pancreatic, and lung cancer as examples.

Mammary ductoscopy in the current management of breast disease

BACKGROUND

The majority of benign and malignant lesions of the breast are thought to arise from the epithelium of the terminal duct-lobular unit (TDLU). Although modern mammography, ultrasound, and MRI have improved diagnosis, a final pathological diagnosis currently relies on percutaneous methods of sampling breast lesions. The advantage of mammary ductoscopy (MD) is that it is possible to gain direct access to the ductal system via the nipple. Direct visualization of the duct epithelium allows the operator to precisely locate intraductal lesions, enabling accurate tissue sampling and providing guidance to the surgeon during excision. The intraductal approach may also have a role in screening individuals who are at high risk of breast cancer. Finally, in spontaneous nipple discharge (SND), as biopsy instruments improve and intraductal therapeutics, such as intraductal excision and laser ablation, become a possibility, normal or benign ductoscopic findings may help minimize surgery in selected patients. As MD technology is rapidly advancing, a comprehensive review of current practice will be a valuable guide for clinicians involved in the management of breast disease.

METHODS

This is a review of current ductoscopic practice based on an exhaustive literature search of Pubmed, Google Scholar, and conference proceedings. The search terms "ductoscopy", "duct endoscopy", "mammary", "breast," and "intraductal" were used.

RESULTS/CONCLUSIONS

Duct endoscopes have become smaller in diameter with working channels and improved optical definition. Currently, the role of MD is best defined in the management of SND facilitating targeted surgical excision, potentially avoiding unnecessary surgery, and limiting the extent of surgical resection for benign disease. The role of MD in breast-cancer screening and breast conservation surgery has yet to be fully defined. Few prospective randomized trials exist in the literature, and these would be crucial to validate current opinion, not only in the benign setting but also in breast oncologic surgery.

Selective release of microRNA species from normal and malignant mammary epithelial cells

MicroRNAs (miRNAs) in body fluids are candidate diagnostics for a variety of conditions and diseases, including breast cancer. One premise for using extracellular miRNAs to diagnose disease is the notion that the abundance of the miRNAs in body fluids reflects their abundance in the abnormal cells causing the disease. As a result, the search for such diagnostics in body fluids has focused on miRNAs that are abundant in the cells of origin. Here we report that released miRNAs do not necessarily reflect the abundance of miRNA in the cell of origin. We find that release of miRNAs from cells into blood, milk and ductal fluids is selective and that the selection of released miRNAs may correlate with malignancy. In particular, the bulk of miR-451 and miR-1246 produced by malignant mammary epithelial cells was released, but the majority of these miRNAs produced by non-malignant mammary epithelial cells was retained. Our findings suggest the existence of a cellular selection mechanism for miRNA release and indicate that the extracellular and cellular miRNA profiles differ. This selective release of miRNAs is an important consideration for the identification of circulating miRNAs as biomarkers of disease.

Breast ductal lavage for assessment of breast cancer biomarkers

Lavage of the ductal systems of the breast provides fluid (DLF) containing hormones and products of hormone actions that may represent more accurately the composition of the breast than samples collected from blood or urine. The present study was undertaken to assess the presence of potential cancer biomarkers, their variation among individuals at high risk for breast cancer, and differences associated with menopause and tamoxifen treatment. Seventy seven tamoxifen-eligible subjects with a 5-year breast cancer risk estimate (Gail > 1.6%)(N = 53) or recently diagnosed breast cancer (N = 24) were offered tamoxifen therapy; those not accepting tamoxifen were under observation only. After six months, all subjects underwent ductal lavage (DL) in an unaffected breast. Estradiol (E2), estrone sulfate, androstenedione, dehydroepiandrosterone (DHEA), DHEA sulfate, progesterone, cathepsin D and epidermal growth factor (EGF) were measured in DLF by immunoassays. Data were expressed as the mass of analyte per mg of protein in DLF and normalized by natural log transformation. With the exception of DHEA, none of the analytes measured were significantly lower in postmenopausal women than in premenopausal women. The mean log(e) concentration difference in estradiol was 10.9%. Tamoxifen treatment for 6 months did not result in a significantly greater concentration of E2 or in any of the other analytes in DLF of pre- or postmenopausal women. The between-duct variance of the concentration of free steroids within the same breast averaged 51% less than that between subjects, and was similar to that of non-diffusible proteins. The maintenance of estradiol concentrations in the breast after menopause demonstrates the importance of local biosynthesis. The fact that DLF E2 does not reflect the high serum concentrations of E2 during tamoxifen treatment indicates that breast concentrations of estradiol may be under feedback control. Unlike studies of low risk populations, progesterone concentrations were not significantly less in postmenopausal than in premenopausal women. The similarity in variance of free steroids and protein analytes between ducts of a breast indicates little transfer of steroids between lobules.

Status of Intraductal Therapy for Ductal Carcinoma in Situ

The intraductal approach is particularly appealing in the setting of ductal carcinoma in situ (DCIS), a preinvasive breast neoplasm that is thought to be entirely intraductal in its extent. Based on an emerging understanding of the anatomy of the ductal system as well as novel techniques to leverage the access accorded by the intraductal approach, researchers are actively exploring how ductal lavage, ductoscopy, and intraductal infusion of therapeutic agents may enhance breast cancer treatment. Both cytologic and molecular diagnostics continue to improve, and work is ongoing to identify the most effective diagnostic biomarkers for DCIS and cancer, although optimal targeting of the diseased duct remains an important consideration. Ductoscopy holds potential in detection of occult intraductal lesions, and ductoscopically guided lumpectomy could increase the likelihood of a more comprehensive surgical excision. Exciting pilot studies are in progress to determine the safety and feasibility of intraductal chemotherapy infusion. These studies are an important starting point for future investigations of intraductal ablative therapy for DCIS, because as our knowledge and techniques evolve, it is likely that DCIS may be the target most amenable to treatment by intraductal therapy. If such studies are successful, these approaches will allow an important and meaningful transformation in treatment options for women diagnosed with DCIS.