Clinicopathologic features, genomic profiles and outcomes of younger vs. older Chinese hormone receptor-positive (HR+)/HER2-negative (HER2-) metastatic breast cancer patients.

Background: Poor outcomes have been widely reported for younger vs. older breast cancer patients, but whether this is due to age itself or the enrichment of aggressive clinical features remains controversial. We have evaluated the clinicopathologic characteristics and genomic profiles of real-world hormone receptor-positive (HR+)/HER2-negative (HER2-) metastatic breast cancer (MBC) patients to examine the determinants of outcome for younger vs. older patients in a single clinical subtype undergoing treatment in the same clinic. Patients and methods: This study included patients presenting at the Peking University Cancer Hospital with primary stage IV or first-line metastatic HR+/HER2- breast cancer who consented to an additional blood draw for genomic profiling prior to treatment. Plasma samples were analyzed with a targeted 152-gene NGS panel to assess somatic circulating tumor DNA (ctDNA) alterations. Genomic DNA (gDNA) extracted from peripheral blood mononuclear cells was analyzed for germline variants using a targeted 600-gene NGS panel. Kaplan-Meier survival analysis was performed to analyze disease free survival (DFS), progression free survival (PFS) and overall survival (OS) in association with clinicopathologic and genomic variables. Results: Sixty-three patients presenting with HR+/HER2- MBC were enrolled in this study. Fourteen patients were < 40 years, 19 were 40-50 years, and 30 were > 50 years at the time of primary cancer diagnosis. No significant associations were observed between age and DFS, PFS or OS. Shorter OS was associated with de novo Stage IV disease (p = 0.002), Luminal B subtype (p = 0.006), high Ki67 index (p = 0.036), resistance to adjuvant endocrine therapy (p = 0.0001) and clinical stage (p = 0.015). Reduced OS was also observed in association with somatic alterations in FGFR1 (p = 0.008), CCND2 (p = 0.012), RB1 (p = 0.029) or TP53 (p = 0.029) genes, but not in association with germline variants. Conclusion: In this group of real-world HR+/HER2- MBC breast cancer patients younger age was not associated with poor outcomes. While current guidelines recommend treatment decisions based on tumor biology rather than age, young HR+ breast cancer patients are more likely to receive chemotherapy. Our findings support the development of biomarker-driven treatment strategies for these patients.

Genomic Complexity Predicts Resistance to Endocrine Therapy and CDK4/6 Inhibition in Hormone Receptor-Positive (HR+)/HER2-Negative Metastatic Breast Cancer.

PURPOSE: Clinical biomarkers to identify patients unlikely to benefit from CDK4/6 inhibition (CDK4/6i) in combination with endocrine therapy (ET) are lacking. We implemented a comprehensive circulating tumor DNA (ctDNA) analysis to identify genomic features for predicting and monitoring treatment resistance. EXPERIMENTAL DESIGN: ctDNA was isolated from 216 plasma samples collected from 51 patients with hormone receptor-positive (HR+)/HER2-negative (HER2-) metastatic breast cancer (MBC) on a phase II trial of palbociclib combined with letrozole or fulvestrant (NCT03007979). Boosted whole-exome sequencing (WES) was performed at baseline and clinical progression to evaluate genomic alterations, mutational signatures, and blood tumor mutational burden (bTMB). Low-pass whole-genome sequencing was performed at baseline and serial timepoints to assess blood copy-number burden (bCNB). RESULTS: High bTMB and bCNB were associated with lack of clinical benefit and significantly shorter progression-free survival (PFS) compared with patients with low bTMB or low bCNB (all P < 0.05). Dominant APOBEC signatures were detected at baseline exclusively in cases with high bTMB (5/13, 38.5%) versus low bTMB (0/37, 0%; P = 0.0006). Alterations in ESR1 were enriched in samples with high bTMB (P = 0.0005). There was a high correlation between bTMB determined by WES and bTMB determined using a 600-gene panel (R = 0.98). During serial monitoring, an increase in bCNB score preceded radiographic progression in 12 of 18 (66.7%) patients. CONCLUSIONS: Genomic complexity detected by noninvasive profiling of bTMB and bCNB predicted poor outcomes in patients treated with ET and CDK4/6i and identified early disease progression before imaging. Novel treatment strategies including immunotherapy-based combinations should be investigated in this population.

Identification of mutation patterns and circulating tumour DNA-derived prognostic markers in advanced breast cancer patients.

BACKGROUND: The correlations between circulating tumour DNA (ctDNA)-derived genomic markers and treatment response and survival outcome in Chinese patients with advanced breast cancer (ABC) have not been extensively characterized. METHODS: Blood samples from 141 ABC patients who underwent first-line standard treatment in Peking University Cancer Hospital were collected. A next-generation sequencing based liquid biopsy assay (PredicineCARE) was used to detect somatic mutations and copy number variations (CNVs) in ctDNA. A subset of matched blood samples and tumour tissue biopsies were compared to evaluate the concordance. RESULTS: Overall, TP53 (44.0%) and PIK3CA (28.4%) were the top two altered genes. Frequent CNVs included amplifications of ERBB2 (24.8%) and FGFR1 (8.5%) and deletions of CDKN2A (3.5%). PIK3CA/TP53 and FGFR1/2/3 variants were associated with drug resistance in hormone receptor-positive (HR +) and human epidermal growth factor receptor 2-positive (HER2 +) patients. The comparison of genomic variants across matched tumour tissue and ctDNA samples revealed a moderate to high concordance that was gene dependent. Triple-negative breast cancer (TNBC) patients harbouring TP53 or PIK3CA alterations had a shorter overall survival than those without corresponding mutations (P = 0.03 and 0.008). A high ctDNA fraction was correlated with a shorter progression-free survival (PFS) (P = 0.005) in TNBC patients. High blood-based tumor mutation burden (bTMB) was associated with a shorter PFS for HER2 + and TNBC patients (P = 0.009 and 0.05). Moreover, disease monitoring revealed several acquired genomic variants such as ESR1 mutations, CDKN2A deletions, and FGFR1 amplifications. CONCLUSIONS: This study revealed the molecular profiles of Chinese patients with ABC and the clinical validity of ctDNA-derived markers, including the ctDNA fraction and bTMB, for predicting treatment response, prognosis, and disease progression. TRIAL REGISTRATION: ClinicalTrials.gov ID: NCT03792529. Registered January 3rd 2019, https://clinicaltrials.gov/ct2/show/NCT03792529 .

Dynamic changes in gene alterations during chemotherapy in metastatic castrate resistant prostate cancer.

Docetaxel chemotherapy is a standard treatment option for metastatic castrate resistant prostate cancer (mCRPC) patients. To date, the genomic perturbations underlying the emergence of resistance in mCRPC patients during chemotherapy treatment have not been fully characterized. Previous studies have established that AR, TP53, RB1 and PTEN gene alterations are frequent at this stage of progression and that TP53, RB1 and PTEN, but not AR alterations are associated with poor outcome. However, the clonal dynamics of these key driver cancer genes during chemotherapy in mCRPC patients have not been described. Toward this goal, we performed a retrospective analysis of serially profiled cell-free DNA (cfDNA) alterations in blood samples collected from mCRPC patients before and after starting chemotherapy who were followed for response and clinical outcomes. While AR alterations and measures of mutational load were significantly reduced in patients with stable or decreased PSA levels after 3 cycles of chemotherapy, reductions in RB1, TP53 and PTEN alterations were relatively modest, which may represent the persistence of a clonal signature associated with the emergence of treatment-induced lineage plasticity (TILP) underlying resistance. The ability to monitor these driver gene clonal dynamics during chemotherapy may have utility in the clinical setting.

Circulating Cell-Free DNA-Based Detection of Tumor Suppressor Gene Copy Number Loss and Its Clinical Implication in Metastatic Prostate Cancer.

Current liquid biopsy assays lack sufficient sensitivity to detect copy number loss, which limits the interrogation of critical tumor suppressor gene deletions during cancer progression and treatment. Here we describe a liquid biopsy assay with improved sensitivity for detection of copy number loss in blood samples with low levels of circulating tumor DNA, and demonstrate its utility by profiling PTEN, RB1, and TP53 genetic loss in metastatic prostate cancer patients.

Quantitative Multiplex Immunoassay for Profiling Bone Turnover Biomarkers in Human Bone Tissue Culture Supernatants.

Bone is a metabolically dynamic tissue that is continuously built up and broken down through anabolic and catabolic processes regulated by a variety of systemic and local signaling molecules. Here, we describe quantitative multiplex immunoassay analysis of supernatants collected from cultured human bone tissue fragments to profile local factors associated with the bone turnover process.

Automated Cell Segmentation for Quantitative Phase Microscopy.

Automated cell segmentation and tracking is essential for dynamic studies of cellular morphology, movement, and interactions as well as other cellular behaviors. However, accurate, automated, and easy-to-use cell segmentation remains a challenge, especially in cases of high cell densities, where discrete boundaries are not easily discernable. Here, we present a fully automated segmentation algorithm that iteratively segments cells based on the observed distribution of optical cell volumes measured by quantitative phase microscopy. By fitting these distributions to known probability density functions, we are able to converge on volumetric thresholds that enable valid segmentation cuts. Since each threshold is determined from the observed data itself, virtually no input is needed from the user. We demonstrate the effectiveness of this approach over time using six cell types that display a range of morphologies, and evaluate these cultures over a range of confluencies. Facile dynamic measures of cell mobility and function revealed unique cellular behaviors that relate to tissue origins, state of differentiation, and real-time signaling. These will improve our understanding of multicellular communication and organization.

Local estrogen axis in the human bone microenvironment regulates estrogen receptor-positive breast cancer cells.

BACKGROUND: Approximately 70% of all breast cancers express the estrogen receptor, and are regulated by estrogen. While the ovaries are the primary source of estrogen in premenopausal women, most breast cancer is diagnosed following menopause, when systemic levels of this hormone decline. Estrogen production from androgen precursors is catalyzed by the aromatase enzyme. Although aromatase expression and local estrogen production in breast adipose tissue have been implicated in the development of primary breast cancer, the source of estrogen involved in the regulation of estrogen receptor-positive (ER+) metastatic breast cancer progression is less clear. METHODS: Bone is the most common distant site of breast cancer metastasis, particularly for ER+ breast cancers. We employed a co-culture model using trabecular  bone tissues obtained from total hip replacement (THR) surgery specimens to study ER+ and estrogen receptor-negative (ER-) breast cancer cells within the human bone microenvironment. Luciferase-expressing ER+ (MCF-7, T-47D, ZR-75) and ER- (SK-BR-3, MDA-MB-231, MCF-10A) breast cancer cells were cultured directly on bone tissue fragments or in bone tissue-conditioned media, and monitored over time with bioluminescence imaging (BLI). Bone tissue-conditioned media were generated in the presence vs. absence of aromatase inhibitors, and testosterone. Bone tissue fragments were analyzed for aromatase expression by immunohistochemistry. RESULTS: ER+ breast cancer cells were preferentially sustained in co-cultures with bone tissues and bone tissue-conditioned media relative to ER- cells. Bone fragments analyzed by immunohistochemistry revealed expression of the aromatase enzyme. Bone tissue-conditioned media generated in the presence of testosterone had increased estrogen levels and heightened capacity to stimulate ER+ breast cancer cell proliferation. Pretreatment of cultured bone tissues with aromatase inhibitors, which inhibited estrogen production, reduced the capacity of conditioned media to stimulate ER+ cell proliferation. CONCLUSIONS: These results suggest that a local estrogen signaling axis regulates ER+ breast cancer cell viability and proliferation within the bone metastatic niche, and that aromatase inhibitors modulate this axis. Although endocrine therapies are highly effective in the treatment of ER+ breast cancer, resistance to these treatments reduces their efficacy. Characterization of estrogen signaling networks within the bone microenvironment will identify new strategies for combating metastatic progression and endocrine resistance.

Breast Cancer Cell Colonization of the Human Bone Marrow Adipose Tissue Niche.

BACKGROUND/OBJECTIVES: Bone is a preferred site of breast cancer metastasis, suggesting the presence of tissue-specific features that attract and promote the outgrowth of breast cancer cells. We sought to identify parameters of human bone tissue associated with breast cancer cell osteotropism and colonization in the metastatic niche. METHODS: Migration and colonization patterns of MDA-MB-231-fLuc-EGFP (luciferase-enhanced green fluorescence protein) and MCF-7-fLuc-EGFP breast cancer cells were studied in co-culture with cancellous bone tissue fragments isolated from 14 hip arthroplasties. Breast cancer cell migration into tissues and toward tissue-conditioned medium was measured in Transwell migration chambers using bioluminescence imaging and analyzed as a function of secreted factors measured by multiplex immunoassay. Patterns of breast cancer cell colonization were evaluated with fluorescence microscopy and immunohistochemistry. RESULTS: Enhanced MDA-MB-231-fLuc-EGFP breast cancer cell migration to bone-conditioned versus control medium was observed in 12/14 specimens (P = .0014) and correlated significantly with increasing levels of the adipokines/cytokines leptin (P = .006) and IL-1ß (P = .001) in univariate and multivariate regression analyses. Fluorescence microscopy and immunohistochemistry of fragments underscored the extreme adiposity of adult human bone tissues and revealed extensive breast cancer cell colonization within the marrow adipose tissue compartment. CONCLUSIONS: Our results show that breast cancer cells migrate to human bone tissue-conditioned medium in association with increasing levels of leptin and IL-1ß, and colonize the bone marrow adipose tissue compartment of cultured fragments. Bone marrow adipose tissue and its molecular signals may be important but understudied components of the breast cancer metastatic niche.

Methods for culturing human femur tissue explants to study breast cancer cell colonization of the metastatic niche.

Bone is the most common site of breast cancer metastasis. Although it is widely accepted that the microenvironment influences cancer cell behavior, little is known about breast cancer cell properties and behaviors within the native microenvironment of human bone tissue.We have developed approaches to track, quantify and modulate human breast cancer cells within the microenvironment of cultured human bone tissue fragments isolated from discarded femoral heads following total hip replacement surgeries. Using breast cancer cells engineered for luciferase and enhanced green fluorescent protein (EGFP) expression, we are able to reproducibly quantitate migration and proliferation patterns using bioluminescence imaging (BLI), track cell interactions within the bone fragments using fluorescence microscopy, and evaluate breast cells after colonization with flow cytometry. The key advantages of this model include: 1) a native, architecturally intact tissue microenvironment that includes relevant human cell types, and 2) direct access to the microenvironment, which facilitates rapid quantitative and qualitative monitoring and perturbation of breast and bone cell properties, behaviors and interactions. A primary limitation, at present, is the finite viability of the tissue fragments, which confines the window of study to short-term culture. Applications of the model system include studying the basic biology of breast cancer and other bone-seeking malignancies within the metastatic niche, and developing therapeutic strategies to effectively target breast cancer cells in bone tissues.

Detection of non-melanoma skin cancer by in vivo fluorescence imaging with fluorocoxib A.

Non-melanoma skin cancer (NMSC) is the most common form of cancer in the US and its incidence is increasing. The current standard of care is visual inspection by physicians and/or dermatologists, followed by skin biopsy and pathologic confirmation. We have investigated the use of in vivo fluorescence imaging using fluorocoxib A as a molecular probe for early detection and assessment of skin tumors in mouse models of NMSC. Fluorocoxib A targets the cyclooxygenase-2 (COX-2) enzyme that is preferentially expressed by inflamed and tumor tissue, and therefore has potential to be an effective broadly active molecular biomarker for cancer detection. We tested the sensitivity of fluorocoxib A in a BCC allograft SCID hairless mouse model using a wide-field fluorescence imaging system. Subcutaneous allografts comprised of 1000 BCC cells were detectable above background. These BCC allograft mice were imaged over time and a linear correlation (R(2) = 0.8) between tumor volume and fluorocoxib A signal levels was observed. We also tested fluorocoxib A in a genetically engineered spontaneous BCC mouse model (Ptch1(+/-) K14-Cre-ER2 p53(fl/fl)), where sequential imaging of the same animals over time demonstrated that early, microscopic lesions (100 µm size) developed into visible macroscopic tumor masses over 11 to 17 days. Overall, for macroscopic tumors, the sensitivity was 88% and the specificity was 100%. For microscopic tumors, the sensitivity was 85% and specificity was 56%. These results demonstrate the potential of fluorocoxib A as an in vivo imaging agent for early detection, margin delineation and guided biopsies of NMSCs.

Monitoring dynamic interactions between breast cancer cells and human bone tissue in a co-culture model.

PURPOSE: Bone is a preferential site of breast cancer metastasis, and models are needed to study this process at the level of the microenvironment. We have used bioluminescence imaging (BLI) and multiplex biomarker immunoassays to monitor dynamic breast cancer cell behaviors in co-culture with human bone tissue. PROCEDURES: Femur tissue fragments harvested from hip replacement surgeries were co-cultured with luciferase-positive MDA-MB-231-fLuc cells. BLI was performed to quantify breast cell proliferation and track migration relative to bone tissue. Breast cell colonization of bone tissues was assessed with immunohistochemistry. Biomarkers in co-culture supernatants were profiled with MILLIPLEX(®) immunoassays. RESULTS: BLI demonstrated increased MDA-MB-231-fLuc cell proliferation (p < 0.001) in the presence vs. absence of bones and revealed breast cell migration toward bone. Immunohistochemistry illustrated MDA-MB-231-fLuc cell colonization of bone, and MILLIPLEX(®) profiles of culture supernatants suggested breast/bone crosstalk. CONCLUSIONS: Breast cell behaviors that facilitate metastasis occur reproducibly in human bone tissue co-cultures and can be monitored and quantified using BLI and multiplex immunoassays.

The intraductal approach to the breast: raison d'être.

Opportunities for the detection, prediction, and treatment of breast cancer exist at three biological levels: systemically via the blood, at the whole organ level, and within the individual ductal lobular structures of the breast. This review covers the evaluation of approaches targeted to the ductal lobular units, where breast cancer begins. Studies to date suggest the presence of 5 to 12 independent ductal lobular systems per breast, each harboring complex cellular fluids contributed by local and systemic processes. New techniques for accessing and interrogating these systems offer the potential to gauge the microenvironment of the breast and distill biological risk profiles.

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.

The Fourth International Symposium on the Intraductal Approach to Breast Cancer, Santa Barbara, California, 10-13 March 2005.

Intraductal approaches encompass procedures and technologies that are designed to access and interrogate the ductal-alveolar systems of the human breast, and include nipple aspiration, ductal lavage, random periareolar fine needle aspiration, and ductoscopy. These approaches are being used to collect and analyze fluids and cells to develop methods for breast cancer detection and risk assessment; to introduce imaging technologies to explore the mammary tree for abnormalities; to administer therapeutic and/or preventive agents directly to the breast tissue; and to explore the biology of the normal mammary gland. The latest research findings in these areas, presented at The 4th International Symposium on the Intraductal Approach to Breast Cancer in 2005, are summarized in this report.

A comparison of five immunohistochemical biomarkers and HER-2/neu gene amplification by fluorescence in situ hybridization in white and Korean patients with early-onset breast carcinoma.

BACKGROUND: The objective of this article was to compare five tumor markers between white women in the U.S. and native Korean women with early-onset breast carcinoma. METHODS: Sixty Korean women who were diagnosed with breast carcinoma at age 45 years or younger and 60 white women with breast carcinoma who were matched by age were selected for this study. The median age of both groups was 37 years. Paraffin embedded blocks of the primary tumor were processed for immunohistochemical staining of estrogen receptor (ER), progesterone receptor (PR), p53, cyclin D1, and HER-2/neu. RESULTS: The proportion of tumors that stained positive for ER, PR, p53, and cyclin D1 in the Korean women were 47.5%, 42.4%, 28.8%, and 40.9%, respectively; in the white women, the proportions were 43.9%, 52.6%, 21.1%, and 59.1%, respectively. The differences between the white patients and the Korean patients were not statistically significant with respect to any of those variables. A significant difference was found in the expression of HER-2/neu. Specifically, positive HER-2/neu status was observed in 47.5% of Korean women, compared with overexpression in only 15.8% of white women (P < 0.001). Fluorescence in situ hybridization analysis for HER-2/neu gene amplification on all HER-2/neu positive samples that scored 2 + and 3 + demonstrated a significant difference (P = 0.007) in gene amplification between the two populations. Differences in HER-2/neu positivity were observed for the entire cohort as well as among the subsets of patients with negative and positive lymph node status. No association was found between immunoreactivity for the five markers and axillary lymph node metastasis. CONCLUSIONS: The findings of high positivity of HER-2/neu expression and gene amplification in Korean women with early-onset breast carcinoma may have potential implications for local and systemic management of breast carcinoma, especially anti-HER-2/neu therapy for patients with hormone receptor negativity. Further research will be needed to identify biologic and genetic factors and their effects on the survival between different racial groups.

Quantitative analysis of breast cancer tissue microarrays shows that both high and normal levels of HER2 expression are associated with poor outcome.

Using a tissue microarray cohort of 300 breast cancers and 84 samples of normal breast epithelium, we analyzed HER2/neu expression and compared traditional clinical (manual) scoring with a recently developed system for the quantitative measurement of immunohistochemical stains (AQUA). As expected, both methods identified a population (10-15%) of high-HER2-expressing tumors with poor 30-year disease-related survival. Using AQUA analysis, we found that normal epithelium expresses a low but detectable level of HER2 and that 17.5% of tumors exhibit similar low-level HER2 expression. This low group was not definable by manual scoring. Surprisingly, HER2-normal tumors were as aggressive as HER2-overexpressing tumors. Our studies suggest that in situ quantitative measurement of HER2 stratifies breast tumors into three expression levels: normal, intermediate, and high, where both normal and high levels are associated with a worse outcome.

Detection of chromosomal instability in paired breast surgery and ductal lavage specimens by interphase fluorescence in situ hybridization.

PURPOSE: Ductal lavage is a new modality for collecting exfoliated breast cells with the goal of detecting early neoplasia. The purpose of our study was to evaluate the correlation between cancer-associated abnormalities in breast lesions and exfoliated breast cells collected by ductal lavage. EXPERIMENTAL DESIGN: We performed histopathologic, cytologic, and molecular cytogenetic analyses on 39 paired cases of surgically excised breast lesions and ductal lavage specimens collected immediately before surgery. RESULTS: Abnormal cytology was detected in 7 of 15 (47%) of the evaluable lavages collected from malignant cases, versus 4 of 19 (21%) of the evaluable lavages harvested from benign cases for a sensitivity and specificity of 47 and 79%, respectively. Interphase fluorescence in situ hybridization analysis of all evaluable lavages revealed numeric changes on chromosomes 1, 8, 11, and/or 17 in 10 of 14 (71%) specimens from malignant cases versus 2 of 18 (11%) from benign cases for a sensitivity and specificity of 71 and 89%, respectively. CONCLUSIONS: Our study demonstrates that cytologic and genetic abnormalities associated with breast cancer progression can be detected in ductal lavage cells collected from women with in situ and invasive breast cancer and suggests that fluorescence in situ hybridization may have superior sensitivity and specificity compared with conventional cytology.

Immunocytochemical analysis of breast cells obtained by ductal lavage.

BACKGROUND: Intraductal breast fluids containing exfoliated mammary epithelial cells can be harvested from the breast by ductal lavage to screen for disease-associated cytologic abnormalities. In addition to epithelial cells, breast fluids contain large numbers of mammary foam cells, and the tissue of origin of these foam cells has been the subject of controversy for many years. Immunocytochemical, morphologic, and molecular studies variously have supported a mammary epithelial origin versus a histiocytic origin for this cell type. In the current study, the authors performed immunocytochemical analysis with epithelial specific and macrophage specific antibodies to characterize and quantify breast cells obtained by ductal lavage. METHODS: Breast fluids were harvested from 19 individual breast ducts in 15 female patients by ductal lavage. Cells from each specimen were processed for immunocytochemical staining using the AE1/AE3 multicytokeratin and CD68 (clone KP1) monoclonal antibodies. Cells were classified as mammary epithelial cells or mammary foam cells on the basis of morphologic criteria, and the cells were counted and evaluated for immunoreactivity with epithelial specific and macrophage specific antibodies. RESULTS: The CD68 macrophage specific antibody stained all ductal lavage cells that exhibited foam cell morphology. The AE1/AE3 multicytokeratin antibody demonstrated strong, positive staining of cells that exhibited epithelial morphology but failed to demonstrate significant staining of mammary foam cells. The lavage specimens contained a range of 3040-278,850 epithelial cells and 2230-90,480 foam cells. The median numbers of epithelial cells and foam cells per lavage sample were 15,680 and 29,200, respectively. The ratio of epithelial cells to foam cells varied among specimens ranging from 3.4 to 0.09 (median, 0.8). Seven of 19 lavage specimens contained more epithelial cells than foam cells, whereas 12 samples contained a greater proportion of foam cells. CONCLUSIONS: Immunocytochemical analysis using the AE1/AE3 multicytokeratin and CD68 antibodies supports a histiocytic origin for the majority of mammary foam cells harvested from the ductal system of the human breast by ductal lavage. Although mammary foam cells constitute a significant proportion of the cellular population obtained by ductal lavage, thousands of epithelial cells also are harvested.