Gene expression profile of normal breast tissue and body mass index.

BACKGROUND: In human breast, adipose tissue represents up to 80% of the total volume and plays a critical role in mammary gland remodeling. Given the emerging role of obesity in breast cancer growth and development, we explored the relationship between body mass index (BMI), as a proxy of woman's obesity status, and the expression in normal breast tissue from healthy women of a selected panel of genes, known to be involved in mammary gland homeostasis. METHODS: Two independent publicly available datasets, composed of 180 specimens of normal breast tissue from reduction mammoplasty were interrogated. Differential gene expression among BMI classes was evaluated by ANOVA, and partial correlation coefficient was used to assay the correlation between genes controlling for BMI. RESULTS: Despite the differences in microarray platforms and analytical procedures, the two datasets shared a core of 9 genes differentially expressed in BMI classes and significantly correlated with BMI. Four (44%) of these genes belong to the functional class of cytokines and cytokine receptors (IL1R1, IL2RA, IL12A, and IL12RB2). The others belong to the functional class of the epigenetic regulation (MEDAG and SETD7), signal transduction (STAT1), cell adhesion (ITGAV), and enzymatic activity (STS). CONCLUSIONS: Although exploratory, present findings are in agreement with the role of inflammation modulators in the homeostasis of normal breast tissue and the believe that an increase in body adipose tissue may have a potentially dangerous local effect, through the increased expression of inflammation-related genes and the establishment of a low-grade chronic inflammation.

Impact of sex hormones dysregulation and adiposity on the outcome of postmenopausal breast cancer patients.

Epidemiological studies demonstrated that, in postmenopausal women, high circulating levels of testosterone, especially when associated with weight gain, positively correlated with an increased risk of breast cancer because of the augmented production of oestrogen via testosterone aromatization in the adipose tissue. Besides, growing evidence suggests that sulfatase can increase the tissue concentration of bioactive estradiol through the reconversion of estrone sulfate, thus providing a favourable milieu for epithelial cells expressing the oestrogen receptor. In this review, we will discuss how the "obesity-insulin-testosterone" connection and the abnormal production of bioactive oestrogen - as a result of the conversion of the androgens by aromatase and the estrone reconversion by sulfatase-, may affect the response to hormone therapy and the outcome of postmenopausal breast cancer patients, and how a combined therapy including metformin, anti-inflammatory drugs, and aromatase/sulfatase inhibitors could successfully improve patient's outcome.

Adipokines expression and epithelial cell polarity in normal and cancerous breast tissue.

Cell polarity is crucial for the correct structural and functional organization of epithelial tissue. Its disruption can lead to loss of the apicobasal polarity, alteration in the intracellular components, misregulation of the pathways involved in cell proliferation and cancer promotion. Very recent in vitro/in vivo findings demonstrated that obesity-associated alterations in tissue adipokines protein level negatively affect epithelial polarity. We performed an in silico study to investigate whether such alterations also occur in surgical samples. We aimed to explore the relationship among the expression of the genes coding for leptin (LEP), adiponectin (ADIPOQ), adipokine receptors (LEPR, ADIPOR1 and ADIPOR2), and a panel of polarity-associated genes in normal tissue from breast reduction mammoplasty, and a series of paired samples of histologically normal (HN) tissue and invasive cancer. Results indicated that, in normal tissue, the expression of adipokines and their receptors negatively correlated with that of the polarity-associated genes and GGT1, which codes for γ-glutamyl transferase (GGT) enzyme, a marker of cell distress and membrane disruption. This negative correlation progressively decreased in HN and cancerous tissue, and loss of correlation between ADIPOR2 and polarity-associated genes appeared the most noticeable alteration. Given the growing role of obesity in breast cancer etiology and the opposite action of leptin and adiponectin in epithelial tissue remodeling, ADIPOR2 loss could be addressed as a key mechanism leading to an unbalanced leptin stimulatory activity, subsequent cell polarity disruption and eventually tumor initiation, a finding that requires to be confirmed also at the protein level and with in vivo models.

Body mass index and γ-glutamyl transferase expression in normal and cancerous breast tissue.

BACKGROUND: Localized to cell membrane, γ-glutamyl transferase (GGT) is a reliable marker for the evaluation of cell distress occurring in several pathological conditions including obesity, metabolic syndrome, and cancer. In particular, high GGT serum levels are associated with breast cancer incidence and progression. METHODS: The tissue expression of GGT1, the gene coding for GGT, was investigated in silico in a large case series of paired samples of breast cancer and adjacent histologically normal (HN) tissue, and in a collection of healthy breast tissues from reduction mammoplasty. The association of GGT1 with patient's body mass index (BMI), and the relationship between GGT1 and a panel of genes involved in apoptosis, IGF-1 signaling, or coding for adipokines and adipokine receptors were also investigated. RESULTS: GGT1 expression was significantly higher in tumor than in the adjacent HN tissue (P = 0.0002). Unexpectedly, the expression of GGT1 was inversely associated with BMI in normal and HN tissue, whereas no correlation was found in cancerous tissue. In all tissues, GGT1 correlated positively with TP53 and negatively with BCL2 and LEPR, whereas only in normal and HN tissue GGT1 correlated positively with IGF1R. The linear regression model, adjusted for BMI, showed no confounding effect on any correlation, except for the correlation of GGT1 with LEPR in normal tissue from healthy women. CONCLUSIONS: Even if present results provide interesting insights on the still elusive mechanism(s) underlying the association between obesity and epithelial cell proliferation, possibly promoting neoplastic transformation, such relationship deserves further investigation in other independent datasets.

Serum levels of testosterone and SHBG in association with body mass index improve the predictive capability of consolidate tumor biomarkers in pre- and postmenopausal breast cancer patients.

OBJECTIVE: To investigate the contribution of serum levels of testosterone (TS) and sex hormone binding globulin (SHBG) in association with body mass index (BMI) as a surrogate marker of obesity, to the predictive capability of tumor size (T), lymph node (N) and estrogen receptor (ER) status and proliferative activity (TLI). METHODS: We investigated 120 women with primary breast cancer and median follow-up of 138 months. Serum levels of TS and SHBG and patient's BMI were evaluated before surgery. The contribution of TS, SHBG, their ratio (TS/SHBG) and BMI to the predictive capability of tumor-specific biomarkers was investigated by Harrell's c statistic. RESULTS: TS alone did not affect prognosis, whereas SHBG was protective in postmenopausal patients, in which BMI was associated with a progressive increase in the relapse-specific hazard ratio (HR). When in combination, TS, SHBG and BMI, affected prognosis in different ways depending on menopausal status. The best predictive capability (c = 0.78) was observed in postmenopausal patients when at the basic model (N + TLI) were added TS, BMI, TS * BMI interaction, with or without SHBG. In premenopause subgroup, the best predictive capability (c = 0.67) was provided by the basic model (N + TLI) plus TS and SHBG or their ratio, BMI and TS * BMI or TS/SHBG * BMI interaction. CONCLUSIONS: Patient-associated features such as BMI and serum levels of TS and SHBG can improve the predictive capability of consolidate tumor-specific biomarkers in both pre- and postmenopause, thus providing a relevant contribution to the decision-making process.

Epithelial cell identity in hyperplastic precursors of breast cancer.

INTRODUCTION: In the adult human breast, hyperplastic enlarged lobular unit (HELU) and atypical ductal hyperplasia (ADH) are two common abnormalities that frequently coexist with ductal carcinoma in situ (DCIS). For this reason, they have been proposed as the early steps in a biological continuum toward breast cancer. METHODS: We investigated in silico the expression of 369 genes experimentally recognized as involved in establishing and maintaining epithelial cell identity and mammary gland remodeling, in HELUs or ADHs with respect to the corresponding patient-matched normal tissue. RESULTS: Despite the common luminal origin, HELUs and ADHs proved to be characterized by distinct gene profiles that overlap for 5 genes only. While HELUs were associated with the overexpression of progesterone receptor (PGR), ADHs were characterized by the overexpression of estrogen receptor 1 (ESR1) coupled with the overexpression of some proliferation-associated genes. CONCLUSIONS: This unexpected finding contradicts the notion that in differentiated luminal cells the expression of estrogen receptor (ER) is dissociated from cell proliferation and suggests that the establishing of an ER-dependent signaling is able to sustain cell proliferation in an autocrine manner as an early event in tumor initiation. Although clinical evidence indicates that only a fraction of HELUs and ADHs evolve to invasive cancer, present findings warn that exposure to synthetic progestins, frequently administered as hormone-replacement therapy, and estrogens, when abnormally produced by adipose cells and persistently present in the stroma surrounding the mammary gland, may cause these hyperplastic lesions.

Differential expression of genes involved in the epigenetic regulation of cell identity in normal human mammary cell commitment and differentiation.

The establishment and maintenance of mammary epithelial cell identity depends on the activity of a group of proteins, collectively called maintenance proteins, that act as epigenetic regulators of gene transcription through DNA methylation, histone modification, and chromatin remodeling. Increasing evidence indicates that dysregulation of these crucial proteins may disrupt epithelial cell integrity and trigger breast tumor initiation. Therefore, we explored in silico the expression pattern of a panel of 369 genes known to be involved in the establishment and maintenance of epithelial cell identity and mammary gland remodeling in cell subpopulations isolated from normal human mammary tissue and selectively enriched in their content of bipotent progenitors, committed luminal progenitors, and differentiated myoepithelial or differentiated luminal cells. The results indicated that, compared to bipotent cells, differentiated myoepithelial and luminal subpopulations were both characterized by the differential expression of 4 genes involved in cell identity maintenance: CBX6 and PCGF2, encoding proteins belonging to the Polycomb group, and SMARCD3 and SMARCE1, encoding proteins belonging to the Trithorax group. In addition to these common genes, the myoepithelial phenotype was associated with the differential expression of HDAC1, which encodes histone deacetylase 1, whereas the luminal phenotype was associated with the differential expression of SMARCA4 and HAT1, which encode a Trithorax protein and histone acetylase 1, respectively. The luminal compartment was further characterized by the overexpression of ALDH1A3 and GATA3, and the down-regulation of NOTCH4 and CCNB1, with the latter suggesting a block in cell cycle progression at the G2 phase. In contrast, myoepithelial differentiation was associated with the overexpression of MYC and the down-regulation of CCNE1, with the latter suggesting a block in cell cycle progression at the G1 phase.

Cell identity disruption in breast cancer precursors.

BACKGROUND: Mammary epithelial cell identity depends on a set of genes epigenetically-regulated by maintenance proteins, the best-characterized of which belong to the Trithorax and Polycomb groups. Perturbations in expression of these proteins may disrupt cell identity and trigger tumor initiation. MATERIALS AND METHODS: The pattern of expression of a panel of genes involved in control of cell identity and mammary gland remodeling was investigated in two precancerous lesions, atypical ductal hyperplasia (ADH) and ductal carcinoma in situ (DCIS) and compared to the corresponding histologically normal tissue. RESULTS: ADH and DCIS showed a close association in overexpression of Polycomb complex components, silencing of Homeobox A (HOXA) cluster gene, and overexpression of the genes involved in estrogen signaling, specifically, forkhead box A1 (FOXA1) and GATA binding protein 3 (GATA3) pioneer factors, and estrogen receptor-1 (ESR1). CONCLUSION: Our findings support the hypothesis that disruption of epigenetic control is associated with loss of cell identity and acquisition of a constitutive estrogen-dependent terminally-differentiated luminal phenotype.

The role of maintenance proteins in the preservation of epithelial cell identity during mammary gland remodeling and breast cancer initiation.

During normal postnatal mammary gland development and adult remodeling related to the menstrual cycle, pregnancy, and lactation, ovarian hormones and peptide growth factors contribute to the delineation of a definite epithelial cell identity. This identity is maintained during cell replication in a heritable but DNA-independent manner. The preservation of cell identity is fundamental, especially when cells must undergo changes in response to intrinsic and extrinsic signals. The maintenance proteins, which are required for cell identity preservation, act epigenetically by regulating gene expression through DNA methylation, histone modification, and chromatin remodeling. Among the maintenance proteins, the Trithorax (TrxG) and Polycomb (PcG) group proteins are the best characterized. In this review, we summarize the structures and activities of the TrxG and PcG complexes and describe their pivotal roles in nuclear estrogen receptor activity. In addition, we provide evidence that perturbations in these epigenetic regulators are involved in disrupting epithelial cell identity, mammary gland remodeling, and breast cancer initiation.

Cell polarity, epithelial-mesenchymal transition, and cell-fate decision gene expression in ductal carcinoma in situ.

Loss of epithelial cell identity and acquisition of mesenchymal features are early events in the neoplastic transformation of mammary cells. We investigated the pattern of expression of a selected panel of genes associated with cell polarity and apical junction complex or involved in TGF-ß-mediated epithelial-mesenchymal transition and cell-fate decision in a series of DCIS and corresponding patient-matched normal tissue. Additionally, we compared DCIS gene profile with that of atypical ductal hyperplasia (ADH) from the same patient. Statistical analysis identified a "core" of genes differentially expressed in both precursors with respect to the corresponding normal tissue mainly associated with a terminally differentiated luminal estrogen-dependent phenotype, in agreement with the model according to which ER-positive invasive breast cancer derives from ER-positive progenitor cells, and with an autocrine production of estrogens through androgens conversion. Although preliminary, present findings provide transcriptomic confirmation that, at least for the panel of genes considered in present study, ADH and DCIS are part of a tumorigenic multistep process and strongly arise the necessity for the regulation, maybe using aromatase inhibitors, of the intratumoral and/or circulating concentration of biologically active androgens in DCIS patients to timely hamper abnormal estrogens production and block estrogen-induced cell proliferation.

Epithelial cell polarity and tumorigenesis: new perspectives for cancer detection and treatment.

Loss of cell-cell adhesion and cell polarity is commonly observed in tumors of epithelial origin and correlates with their invasion into adjacent tissues and formation of metastases. Growing evidence indicates that loss of cell polarity and cell-cell adhesion may also be important in early stage of cancer. In first part of this review, we delineate the current understanding of the mechanisms that establish and maintain the polarity of epithelial tissues and discuss the involvement of cell polarity and apical junctional complex components in tumor pathogenesis. In the second part we address the clinical significance of cell polarity and junctional complex components in cancer diagnosis and prognosis. Finally, we explore their potential use as therapeutic targets in the treatment of cancer.

The controversial clinicobiological role of breast cancer stem cells.

Breast cancer remains a leading cause of morbidity and mortality in women mainly because of the propensity of primary breast tumors to metastasize. Growing experimental evidence suggests that cancer stem cells (CSCs) may contribute to tumor progression and metastasis spread. However, despite the tremendous clinical potential of such cells and their possible therapeutic management, the real nature of CSCs remains to be elucidated. Starting from what is currently known about normal mammary stem/progenitor cells, to better define the cell that originates a tumor or is responsible for metastatic spread, this review will discuss experimental evidence of breast cancer stem cells and speculate about the clinical importance and implications of their evaluation.

A randomized trial comparing axillary dissection to no axillary dissection in older patients with T1N0 breast cancer: results after 5 years of follow-up.

SUMMARY BACKGROUND DATA: Axillary dissection, an invasive procedure that may adversely affect quality of life, used to obtain prognostic information in breast cancer, is being supplanted by sentinel node biopsy. In older women with early breast cancer and no palpable axillary nodes, it may be safe to give no axillary treatment. We addressed this issue in a randomized trial comparing axillary dissection with no axillary dissection in older patients with T1N0 breast cancer. METHODS: From 1996 to 2000, 219 women, 65 to 80 years of age, with early breast cancer and clinically negative axillary nodes were randomized to conservative breast surgery with or without axillary dissection. Tamoxifen was prescribed to all patients for 5 years. The primary endpoints were axillary events in the no axillary dissection arm, comparison of overall mortality (by log rank test), breast cancer mortality, and breast events (by Gray test). RESULTS: Considering a follow-up of 60 months, there were no significant differences in overall or breast cancer mortality, or crude cumulative incidence of breast events, between the 2 groups. Only 2 patients in the no axillary dissection arm (8 and 40 months after surgery) developed overt axillary involvement during follow-up. CONCLUSIONS: Older patients with T1N0 breast cancer can be treated by conservative breast surgery and no axillary dissection without adversely affecting breast cancer mortality or overall survival. The very low cumulative incidence of axillary events suggests that even sentinel node biopsy is unnecessary in these patients. Axillary dissection should be reserved for the small proportion of patients who later develop overt axillary disease.

Metástase de adenocarcinoma de mama em cérvix uterina: relato de caso / Breast adenocarcinoma metastasis of cervix uteri: report of case

A frequência de metástases de carcinoma mamário no útero varia, segundo a literatura, de 2 porcento a 5 porcento dos casos. Os autores apresentam um caso de adenocarcinoma de mama com metástase em paracérvix e miométrio. A paciente submetida a histerectomia total e ooforectomia bilateral. A discussäo sobre o diagnóstico e tratamento é baseada na revisäo da literatura.