Microbial Biomarkers of Breast Tumor and Mastitis: Deciphering the Delicate Balance between Potentially “Evil” and “Benign” Alliances in Mammary Microbiomes

Estrogens Determine Adherens Junction Organization and E-Cadherin Clustering in Breast Cancer Cells via Amphiregulin.

Circular RNAs (circRNAs), a novel class of noncoding RNAs, are reported to be involved in the progression of various cancers. CircDDX17 was reported as a tumour suppressor in colorectal cancer. However, the expression and role of circDDX17 in breast cancer remain unclear. We used qPCR analysis to reveal the expression levels of circRNAs and miRNAs in breast cancer tissues and cell lines. The target relationship between circRNA and miRNAs was predicted using miRanda and then detected using a Luciferase reporter assay. The effects of circDDX17 and miR-605 on the growth of breast cancer were detected using MTT, colony formation assay and apoptosis analysis. In this study, low circDDX17 expression was observed in breast cancer tissues and cell lines. Moreover, circDDX17 expression was inversely associated with the clinicopathological parameters of tumour grade and advanced TNM stage (p<0.05). Functionally, overexpressed circDDX17 inhibited cell proliferation and colony formation and promoted cell apoptosis in breast cancer. Mechanistically, circDDX17 directly bound to miR-605, which functions as an oncogene in breast cancer, and its expression was associated with low overall survival of breast cancer patients. Finally, we found that circDDX17 suppressed cell proliferation by regulating cell cycle-related factors (CDK1 and p21), and the effect was reversed by miR-605 mimics. We identified the downregulation of circDDX17 in breast cancer, and circDDX17 acted as a tumour suppressor by inhibiting proliferation and promoting apoptosis through its function as a sponge of miR-605 in breast cancer, indicating that it serves as a potential biomarker and a therapeutic target for breast cancer.

Tomato is a nutrient-rich vegetable crop plant consumed worldwide. Tomato is a fruit-bearing crop plant of the Solanaceae family. This plant harbors diverse microbes in its rhizosphere, phyllosphere, and endosphere, of which, beneficial microbes can promote their growth, and harmful pathogens can cause various diseases and play a crucial role in determining their overall growth, development, and fitness. Since the plant is being colonized by both beneficial and harmful microbes, the tomato has become an excellent model system for the study of plant-microbe interactions. Besides, their yield is limited due to several pathogen attacks. Therefore, it is crucial to understand both the disease biology and the interaction of beneficial microbes with the tomato plant to obtain extensive knowledge which would ultimately help to find out the possible mechanisms for controlling diseases in tomatoes as well as other Solanaceae crops like potatoes, eggplant, etc. for sustainable agriculture. Here in this chapter, we will discuss the details of the biology of the interaction of both the beneficial and harmful microbes with the tomato plant.

Capillary morphogenesis gene 2 (CMG2) is involved in prostate and breast cancer progression. This study aimed to investigate sex hormone receptor-mediated regulation of CMG2 in breast and prostate cancer, and its implication in disease progression. Expression of CMG2, oestrogen receptor (ER) and androgen receptor (AR) was determined in breast and prostate cancer cell lines, respectively, using real-time quantitative PCR (QPCR) and western blot. Association between CMG2 and sex hormone receptors was analysed in a number of transcriptome datasets. Immunochemical staining was performed in tissue microarrays of breast cancer (BR1505D) and prostate cancer (PR8011A). CMG2 expression was determined in 17β-oestradiol treated breast cancer cells and AR over-expressing prostate cancer cells. CMG2 was found to be inversely correlated with sex hormone receptors in breast and prostate cancer. Lower expression of CMG2 was associated with a poor prognosis in ER (+) breast cancer but not ER (-) tumours. Both ER (+) breast cancer cell lines and AR (+) prostate cancer cell lines presented lower expression of CMG2, which was increased following sex hormone deprivation. Exposure to 17-β-oestradiol and AR over-expression repressed CMG2 expression in breast cancer and prostate cancer cell lines, respectively. CMG2 is inversely correlated with ER and AR status in breast and prostate cancer, respectively. ER and AR mediate repression of CMG2 expression in corresponding cancerous cells.

BackgroundIncreased collagen deposition provides physical and biochemical signals to support tumor growth and invasion during breast cancer development. Therefore, inhibition of collagen synthesis and deposition has been considered a strategy to suppress breast cancer progression. Collagen prolyl-4-hydroxylase α subunit 2 (P4HA2), an enzyme hydroxylating proline residues in -X-Pro-Gly- sequences, is a potential therapeutic target for the disorders associated with increased collagen deposition. However, expression and function of P4HA2 in breast cancer progression are not well investigated.MethodsGene co-expression analysis was performed in the published microarray datasets to identify potential regulators of collagen I, III, and IV in human breast cancer tissue. Expression of P4HA2 was silenced by shRNAs, and its activity was inhibited by 1, 4-DPCA, a prolyl-4-hydroxylase inhibitor. Three-dimensional culture assay was used to analyze roles of P4HA2 in regulating malignant phenotypes of breast cancer cells. Reduced deposition of collagen I and IV was detected by Western blotting and immunofluorescence. Control and P4HA2-silenced breast cancer cells were injected into fat pad and tail vein of SCID mice to examine effect of P4HA2 on tumor growth and lung metastasis.ResultsUsing gene co-expression analysis, we showed that P4HA2 was associated with expression of Col1A1, Col3A1, and Col4A1 during breast cancer development and progression. P4HA2 mRNA levels were significantly upregulated in breast cancer compared to normal mammary tissue. Increased mRNA levels of P4HA2 correlated with poor clinical outcome in breast cancer patients, which is independent of estrogen receptor status. Silencing P4HA2 expression or treatment with the P4HA inhibitor significantly inhibited cell proliferation and suppressed aggressive phenotypes of breast cancer cells in 3D culture, accompanied by reduced deposition of collagen I and IV. We also found that knockdown of P4HA2 inhibited mammary tumor growth and metastasis to lungs in xenograft models.ConclusionThese results suggest the critical role of P4HA2 in breast cancer progression and identify P4HA2 as a potential therapeutic target and biomarker for breast cancer progression.

Differential Methylation Profile of Ovarian Cancer in Tissues and Plasma

Background:Bone morphogenetic protein -4 (BMP-4) plays important role in many aspects of carcinogenesis but is also involved in progression and metastasis of breast cancer where its precise role is yet to be elucidated.Objective:Since the majority of studies related to BMP-4 expression in breast cancer were conducted on cell lines of mouse models, we aimed to investigate BMP-4 tissue expression in primary human breast cancer and to correlate it with standard pathological factors for breast cancer, progression and survival.Methods:We analyzed immunohistochemical expression of BMP-4 in primary breast cancer tissue of 97 patients, correlated it with standard pathological factors for breast cancer and investigated its impact on progression and survival.Results:BMP-4 expression was positive in 74.23% breast cancer tissue specimens. We found that hormone positive breast tumors are more likely to show BMP-4 strong granular staining pattern (p<0.01; p=0.029, respectively). There was significant association between stage group and BMP-4 expression in order that stage III breast cancer group were predominantly BMP-4 positive tumors (p=0.046). Although the most common site of distant metastases in patients with BMP-4 positive tumors were bones, we found no significant association (p>0.05). Patients with BMP-4 positive breast cancer showed longer overall and progression-free survival, but the results did not reach statistical significance (p>0.05).Conclusion:The results of our study in some extent can confirm the current available data and suggest that the role of BMP-4 in breast cancer is ambiguous, acting both as tumor suppressor and tumor promoter in breast cancer. For final elucidation of its impact on survival and progression in breast cancer, multicentric studies on larger sample size are required.

Anticancer or carcinogenic? The role of estrogen receptor β in breast cancer progression

Background Obesity and the insulin resistance syndrome are risk factors for breast cancer and might also affect breast cancer progression. The anti-diabetic drug Metformin (METF) reduces the breast cancer risk in diabetic women. Insulin like growth factor 1 (IGF1) and insulin are involved in breast cancer tumorigenesis and progression. We tested the effect of METF on the IGF1/insulin pathway and its involvement in breast cancer progression. Methods We developed a prognostic signature based on IGF1/insulin pathway genes using the Stockholm breast cancer microarray dataset of 149 cases for training and primary validation and the Uppsala dataset of 249 for external validation. The effect of METF on the prognostic gene set identified was tested in vitro on a panel of breast cancer cell lines. METF effects on proliferation and glucose metabolism were analyzed in vitro and in vivo. The insulin receptor substrate 2 (IRS2) was silenced by transfection with shRNA-lentiviral vectors. Xenograft growth, in the presence and absence of METF, was studied and 18FDG-uptake was measured in vitro and in vivo. Results A 15-gene signature (Insulin sensitivity score, ISS) was developed and predicted breast cancer metastasis with an accuracy similar to the Recurrence Score. ISS genes were expressed at variable levels in a breast cancer cell line panel and showed variable responsiveness to METF. The high expression correlation among the ISS genes observed in untreated breast cancer cell lines was lost upon treatment with METF. METF reduced breast cancer cell growth in vitro with IC50 values ranging from 1mM to 25mM. Growth of MDA-MB-231 cells and hyper-invasive subpopulations derived therefrom was reduced in vivo by oral administration of METF to xenografted nude mice. Response to METF in terms of IC50 values correlated with basal expression of the 15 ISS genes with the strongest inverse correlation observed for IRS2. Stable silencing of IRS2 reduced the MDA-231 cell responsiveness to METF in vitro. Discussion METF acts on the insulin/IGF1 axis by disturbing a network of breast cancer progression related genes and appears to depend in its action on the expression of IRS2 that inversely correlates with the sensitivity of cell lines to the drug. The disruption of the ISS gene network is expected to correlate with an effect on breast cancer growth and progression and in fact, mouse xenografts show reduced growth upon treatment with METF. IRS2 appears to be a major mediator of METF effects. Citation Format: Alessia I. Esposito, Adriana Amaro, Giovanna Angelini, Laura Emionite, Alessandra Gennari, Stefano Indraccolo, Davide Maggi, Cecilia Marini, Barabara Salani, Gianmario Sambuceti, Maria Pia Sormani, Ulrich Pfeffer. Metformin affects breast cancer cell growth and disturbs an IGF1/insulin related gene network that correlates with breast cancer progression. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1182. doi:10.1158/1538-7445.AM2015-1182

Breast and colorectal cancers are among the most common tumor types worldwide and the occurrence of metastases is often associated with a shortened lifespan. One of the signaling pathways that has been frequently associated with metastasis in these tumor entities is the Wnt signaling pathway. Wnt signaling can be either β-catenin dependent (canonical) or βcatenin independent (non-canonical). In breast and colorectal cancer, tumor-promoting properties could be attributed to members of the non-canonical Wnt signaling pathway. Preliminary results showed that overexpression of ROR2 as a non-canonical Wnt receptor, mediated an aggressive phenotype in breast cancer cells and could significantly increase invasion. Accordingly, the first aim of this work was to investigate which ligand binds ROR2 and thus triggers the invasive behavior of MCF-7 cells. RNA-seq analysis revealed increased expression levels of the non-canonical ligand Wnt11 in ROR2 overexpressing cells. Hence, Wnt11 was further investigated as a potential ROR2-ligand. Using co-immunoprecipitation experiments, this work demonstrated the interaction of ROR2 with Wnt11 in human breast cancer cells. To determine which domain facilitates the ROR2-mediated invasion, sequential deletions of the different ROR2 domains were induced. This demonstrated that the cysteine-rich and the tyrosine kinase domain mediate this effect. The next step was to determine whether Wnt11 binds other receptors that trigger the invasive behavior of MCF-7 cells since ROR2 is not expressed in these cells. Furthermore, a cell line screening of different breast and colorectal cancer cell lines identified FZD4 and FZD6 as highly expressed non-canonical Wnt receptors. An interaction between Wnt11 and FZD6 was validated by using Co-IP, in which PTK7 appears to act as a co-receptor. To investigate functional implications of Wnt11-mediated signaling in breast cancer, MCF-7 cells were stimulated with recombinant Wnt11, which caused increased invasion and migration rates, whereas loss of FZD6 resulted in a significant decrease of the elevated invasion rates. In line with the collected data, a signature with non-canonical Wnt pathway members including FZD receptors, ROR receptors, Wnt ligands and PI3K signaling members was defined and was analyzed for its DMFS prognostic values in breast and colorectal cancer patients. Therefore, the signature was applied to gene expression data of primary breast and colorectal cancer patients. For the primary breast cancer patients, the signature clustered the data set into two patient groups, among which the group with high Wnt11 expression was associated with poor DMFS. Considering FZD4 and FZD6 individually, breast cancer patients with high FZD6 gene expression showed worse DMFS, while high FZD4 levels were associated with favorable DMFS. Interestingly, the defined signature clustered the data set of the colorectal cancer patients into four groups and the cohort with a high FZD6 expression exhibited a poor DMFS compared to the other groups. Another important aspect of tumor progression is the reprogramming of the tumor microenvironment. It has been shown that tumor-derived extracellular vesicles can influence the tumor microenvironment in different ways. Preliminary data demonstrated that Wnt proteins can be transported via extracellular vesicles to target cells and induce Wnt signaling responses there. It was shown that RORs are transported on microvesicles and exosomes. Modulation of ROR1 and ROR2 expression resulted in altered protein compositions for both vesicle populations. However, no major impact on vesicle size or concentration was evident. Further analysis addressed functional consequences of ROR1 and ROR2 expression on extracellular vesicles. Tumor-derived EVs isolated from the aggressive breast cancer cell line MDA-MB231 induced invasiveness in MCF-7 cells, which was shown to be dependent on vesicular ROR1 expression. To determine whether ROR1/2 can function as a biomarker in breast cancer patients, plasma-derived microvesicles were analyzed for their ROR1 and ROR2 expression by flow cytometry, which is currently ongoing. In conclusion, this work demonstrated the importance of non-canonical Wnt signaling in breast cancer progression. Wnt11 has been identified as a novel ligand for ROR2 and FZD6 by co-immunoprecipitation experiments, thereby mediating tumor-promoting properties in breast cancer. In particular, it has been shown that ROR proteins not only play an important role in breast cancer cells themselves, but also appear to be additionally involved in vesicle biogenesis and can furthermore be transferred to target cells. A clinical applicability of both ROR proteins regarding their usage as tumor biomarkers for breast cancer is still under investigation.

BackgroundN6-methyladenosine (m6A), the most abundant and reversible modification of mRNAs in eukaryotes, plays pivotal role in breast cancer (BC) tumorigenesis and progression. Circular RNAs (circRNAs) can act as tumor promoters or suppressors by microRNA (miRNA) sponges in BC. However, the underlying mechanism of circRNAs in BC progression via regulating m6A modulators remains unclear.MethodsPrognostic m6A RNA methylation regulators were identified in 1065 BC patients from The Cancer Genome Atlas (TCGA) project. Differentially expressed (DE) miRNAs and DE circRNAs were identified between BC and normal samples in TCGA and GSE101123, respectively. MiRNA-mRNA interactive pairs and circRNA-miRNA interactive pairs were verified by MiRDIP and Circular RNA Interactome. GSEA, KEGG, and ssGSEA were executed to explore the potential biological and immune functions between HNRNPC-high and HNRNPC-low expression groups. qRT-PCR and Western blot were used to quantify the expression of HNRNPC and circBACH2 in MCF-7 and MDA-MB-231 cells. The proliferation of BC cells was assessed by CCK-8 and EdU assay.Results2 m6A RNA methylation regulators with prognostic value, including HNRNPC and YTHDF3, were identified in BC patients. Then, the regulatory network of circRNA-miRNA-m6A modulators was constructed, which consisted of 2 DE m6A modulators (HNRNPC and YTHDF3), 12 DE miRNAs, and 11 DE circRNAs. Notably, BC patients with high expression of HNRNPC and low expression of hsa-miR-944 were correlated with late clinical stages and shorter survival times. Besides, the results from the KEGG inferred that the DE HNRNPC was associated with the MAPK signaling pathway in BC. Moreover, the circBACH2 (hsa_circ_0001625) was confirmed to act as hsa-miR-944 sponge to stimulate HNRNPC expression to promote BC cell proliferation via MAPK signaling pathway, thus constructing a circBACH2/hsa-miR-944/HNRNPC axis in BC.ConclusionsOur findings decipher a novel circRNA-based m6A regulatory mechanism involved in BC progression, thus providing attractive diagnostic and therapeutic strategies for combating BC.

Long non coding RNAs (lncRNAs) have been identified as regulators of the cell cycle, apoptosis, and DNA damage among other processes that if deregulated, may lead to cancer by acting as proto-oncogenes, tumor suppressor genes, and drivers of metastatic transformation. Using RNA sequencing we have identified 42 differentially expressed lncRNAs from a healthy cohort of parous vs. nulliparous women. After bioinformatics and RT-qPCR analysis, we have focused on a vaguely studied lncRNA called BC200 that is highly expressed in the nulliparous postmenopausal breast tissue. It is known that BC200 lncRNA is overexpressed in invasive and pre-invasive breast cancer; however, its functional role in the initiation and progression of breast cancer is poorly understood. In the present work we provide insight on the role of BC200 in the context of luminal and triple negative breast cancer (TNBC). We have confirmed that BC200 is highly expressed in breast cancer tissue and in widely used breast cancer cell lines such as MCF7, T47D, MDAMB231, and Hs578T. Using a lentiviral system we successfully obtained cell lines which stably express BC200. Overexpression of BC200 increases proliferation, migration, and invasion potential in vitro in the cell lines tested, specifically luminal T47D and TNBC MDAMB231. Xenograft studies performed in the mammary fat pad of female SCID mice confirm the role of BC200 as a tumor promoter. Tumors in mice injected with MDAMB231 cells overexpressing BC200 were 4.5 times bigger than tumors in the control group in only 6 weeks when injecting 1 million cells. Moreover, we have determined, using reverse transcriptase PCR targeting genes less than 200 kb from the start site of BC200, that when BC200 is overexpressed, CALM2 is downregulated in both T47D and MDAMB231 cell lines. CALM2 or Calmodulin is a calcium binding protein that plays a role in signaling pathways, cell cycle progression, proliferation, and apoptosis. Mutations in CALM2 are associated with increased risk of breast cancer. Our positive results on Cis regulation are being expanded using chromatin isolation by RNA immunoprecipitation to determine BC200's genome wide regulation. These results demonstrate the participation of BC200 lncRNA in the progression of breast cancer. Notably, BC200 regulates nearby genes that have an implication in cancer progression. BC200, identified in the normal breast tissue of nulliparous women, not only plays a key role in breast cancer progression but also provides a new insight in the preventive role of pregnancy by the downregulation of the expression of this lncRNA in the normal parous breast. [This work was supported by the NCI (National Cancer Institute) Core Grant CA06927 to Fox Chase Cancer Center and generous support from Christian - Diane Martin, the Flyers Wives, and Joseph - Barbara Breitman to Dr. J. Russo, MD]. Citation Format: Barton M, Santucci-Pereira J, Su Y, Russo J. BC200 lncRNA is involved in the progression of triple negative breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-08-06.

INTRODUCTION: Breast cancer is the most common malignancy in the female population and its early diagnosis is important for the success of treatment. Tumor cell-free DNA (cfDNA) circulating in plasma has been suggested as a new potential cancer biomarker. The aim of this study was to quantify the level of plasma cfDNA in plasma of patients with breast carcinoma and determine its correlation with prognostic factors for the disease outcome. MATERIAL AND METHODS: Plasma samples were obtained from 65 women with primary breast cancer and from 29 healthy female controls. Circulatory cfDNA was extracted from the samples and quantified by real-time quantitative PCR for HBB. RESULTS: The mean concentrations of cfDNA 32. 85 ng/ml-1 in breast cancer patients and 17. 08 ng/ml-1 in healthy controls (p=0. 02). Patients with metastatic disease had higher concentrations of cfDNA than patients without metastasis (p=0. 03). No correlation was found between cfDNA concentrations and breast cancer prognostic factors such as hormonal receptors and HER2 status. DISCUSSION AND CONCLUSION: We concluded that the levels of cfDNA are elevated in patients with breast carcinoma. These values are associated with the presence of metastases and advanced-stage tumors. The role of cfDNA as a potential biomarker in breast cancer is suggested.

Postpartum breast cancer (PPBC), diagnosed in the 5-10 years after childbirth, has an elevated risk of metastasis and death. Poor outcomes are thought to be due to factors involved in mammary gland involution, an important stage of mammary gland development. Involution functions to return the mammary gland to the normal post-lactation state and involves activation of multiple processes such as inflammation, wound healing, and lymphangiogenesis. Previously, these processes have been linked to mechanical forces induced by fluid flowing past cells, known as fluid shear stress (FSS). We and others have shown FSS impacts processes associated with lactation and breast cancer metastasis. Herein, we describe the results of a cell model for mimicking lactation and the cessation of lactation as an investigative tool for probing the mechanisms involved in PPBC development and progression. We identified changing levels of FSS as a potential physiologic biomarker through which pathways associated with the progression of PPBC could be identified. The role of fluid shear stress in the progression of cancer remains relatively unexplored, mostly due to practical research barriers. Since FSS cannot be accurately measured in vivo, most research to date has relied on in vitro modelling. In contrast, the role of the involuting mammary gland on the progression of breast cancer has often been studied using rodent models. As a result, studying the interactions between fluid shear stress and involution poses a novel engineering challenge. To address this problem, we developed a bioreactor cell model to enable cell exposure to fluid flow, mimicking forces experienced during lactation, in presence of lactogenic hormones (dexamethasone, insulin, prolactin). Previous work has induced FSS using parallel plate flow chambers, and induced lactation in mammary epithelial cells grown in vitro using lactogenic hormone treatment. To our knowledge, this is the first time these experimental conditions have been studied in combination. We established three distinct stages of treatment, consistent with the fluid shear stress and hormonal levels expected in (1) lactation, (2) cessation of lactation, and (3) involution. To determine whether the model mimicked expected in vivo conditions in the postpartum mammary gland, we used morphological markers and measured the protein expression of β-casein (CSN2), a milk protein that is an established marker of lactation. Each stage was validated and analyzed using proteomic and genomic sequencing. Generated datasets were further analyzed using unsupervised clustering, combining publicly available datasets with our data. We determined that β-casein levels were highest when protein was collected after the lactation stage, followed by an initial drop-off in β-casein expression when fluid shear stress were lowered during the cessation period. The β-casein levels continued at a constant, low level during the involution period, despite a reintroduction of fluid shear stress. This suggests that breast cancer cells are initially responsive to shear stress stimulation, consistent with what would be expected in the postpartum mammary gland in vivo. Proteomic and genomic datasets generated from cells exposed to FSS demonstrated that multiple pathways associated with metastasis are upregulated, as compared to static controls. When combined with publicly available involution datasets, pathways involved in extracellular matrix remodeling, inflammation, and lymphangiogenesis emerged. Multiple targets identified through this analysis have been previously linked to metastatic activities during breast cancer, suggesting that FSS and involution are relevant physiologic biomarkers in the context of PPBC. Work to validate hormonal and fluid shear stress conditions in combination is ongoing. Future work will use the validated model to test relevant targets identified from analysis of generated datasets. Citation Format: Maya Stibbards-Lyle, Kristina Rinker, Laura Hall, Seleem Badawy, Kathy Zhan. Fluid forces and hormone levels during mammary gland development drive changes in breast epithelium that are relevant to the progression of postpartum breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-24-05.

Detection of postmenopausal women at high risk for breast pre-cancer and cancer is a key condition to prevent these diseases. Aim of our research was to study possible usage of immunoassay for antibodies specific to benzo[a]pyrene, estradiol, and progesterone (IgA-Bp, IgA-Es, IgA-Pg) in determination of personal risks for fibrocystic disease and breast cancer at the early stage, with respect to hormone receptor status in tumor tissues. Blood serum IgA-Bp, IgA-Es, IgA-Pg were studied by ELISA in postmenopausal women: healthy controls (n = 401), patients with fibrocystic breast disease (n = 50), and breast cancer (stage I, n = 575, stages II-IV, n = 861). High individual IgA-Bp/IgA-Pg ratios of 1.5 were found in 19.7% of healthy women, and in 50.0% of fibrocystic breast disease patients (p 0.0001; OR = 4.1). IgA-Es/IgA-Pg ratios of 1.0 were revealed in 48.4% healthy women and in 68.0% fibrocystic breast disease patients (p 0.01; OR = 2.3). IgA-Bp/IgAPg values 1.0 were found in 41.9% of healthy women, and, at higher rates, in the patients with breast cancer stage I: 68.3% ER- tumors (p 0.0001; OR = 3.0) and 75.9% ER+ tumors (p 0.0001; OR = 4.4). IgA-Es/ IgA-Pg ratios 1.0 were revealed in 48.4% of healthy women, and in patients with breast cancer stage I: 65.3% ER- tumors (p 0.003; OR = 2.0), and 76.8% ER+ tumors (p 0.0001; OR = 3.5). Some associations of studied antibodies with cancer progression were revealed. Frequency of individual cases with IgA-Bp/IgA-Pg 1.0 in patients with ER- tumors increased from 12.0% at stage I to 19.9% at stage II. Frequency of cases with IgA-Bp/IgA-Pg 1.0 in the patients with ER+ tumors decreased from 62.0% at stage I to 57.3% at stage II (p = 0.002). Frequency of cases with IgA-Es/IgA-Pg 1.0 in the patients with ER- tumors increased from 11.5% at stage I to 21.4% at stage II. Frequency of cases with IgA-Es/IgA-Pg 1.0 in patients with ER+ tumors decreased from 63.3% at stage I to 56.1% at stage II (p 0.001). The cases with individual excessive IgA-Bp and IgA-Es levels are associated with fibrocystic breast disease and ER+ breast cancer at the onset of the disease. Breast cancer progression was associated with the relative decrease of ER in tumor tissues, along with higher individual levels of IgA-Bp and IgА-Es and lower IgA-Pg levels. ELISA testing of IgА-Bp, IgА-Es, IgA-Pg could be recommended for detection of individual risk for fibrocystic breast disease and stage I of breast cancer, as well as for more efficient prevention and therapy by selective modulators of estrogen receptor (raloxifene, arzoxifene and lasofoxifine) and aromatase inhibitors (exemestane, anastrozole).