Following estrogenic activation, the estrogen receptor-␣ (ER␣) directly regulates the transcription of target genes via DNA binding. MicroRNAs (miRNAs) modulated by ER␣ have the potential to fine tune these regulatory systems and also provide an alternate mechanism that could impact on estrogen-dependent developmental and pathological systems. Through a microarray approach, we identify the subset of microRNAs (miRNAs) modulated by ER␣, which include upregulation of miRNAs derived from the processing of the paralogous primary transcripts (pri-) mir-17-92 and mir-106a-363. Characterization of the mir-17-92 locus confirms that the ER␣ target protein c-MYC binds its promoter in an estrogen-dependent manner. We observe that levels of pri-mir-17-92 increase earlier than the mature miRNAs derived from it, implicating precursor cleavage modulation after transcription. Pri-mir-17-92 is immediately cleaved by DROSHA to pre-miR-18a, indicating that its regulation occurs during the formation of the mature molecule from the precursor. The clinical implications of this novel regulatory system were confirmed by demonstrating that pre-miR-18a was significantly upregulated in ER␣-positive compared to ER␣-negative breast cancers. Mechanistically, miRNAs derived from these paralogous pri-miRNAs (miR-18a, miR-19b, and miR-20b) target and downregulate ER␣, while a subset of pri-miRNA-derived miRNAs inhibit protein translation of the ER␣ transcriptional p160 coactivator, AIB1. Therefore, different subsets of miRNAs identified act as part of a negative autoregulatory feedback loop. We propose that ER␣, c-MYC, and miRNA transcriptional programs invoke a sophisticated network of interactions able to provide the wide range of coordinated cellular responses to estrogen.AIB1 ͉ autoregulatory feedback loop ͉ primary transcript ͉ processing U pon 17-␤-estradiol (E2) binding, estrogen receptors (ERs) mediate transcription by interacting directly to specific estrogen response elements (EREs) located in the promoter/ enhancer region of its target genes or indirectly by tethering to nuclear proteins, such as AP1 and SP1 transcription factors (2-4). The cellular response to estrogen is highly regulated at multiple levels including transcription, RNA stability, and posttranslational modifications (5-8). Following treatment with E2, ER␣ transcription and mRNA stability is substantially reduced within 1 h of stimulation (7). Furthermore, E2-ER␣ interactions accelerate receptor degradation through the ubiquitinproteasome pathway, an effect associated with its major coactivator AIB1 (8).MicroRNAs (miRNAs) are a class of noncoding short RNAs, 21-24 nucleotides (nt) in length, that play a role in gene regulation. They downregulate expression of their target genes by base pairing to the 3Ј-UTR of target messenger RNAs (mRNAs) (9). During their biogenesis most miRNAs are transcribed as part of a longer transcript named pri-miRNA (10). These molecules are processed inside the nucleus by DROSHA, producing a pre-miRNA that is a 70-nt ''imperfect'' stem loop ...

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Oestrogen receptor α (ERα) is a nuclear receptor that is the driving transcription factor expressed in the majority of breast cancers. Recent studies have demonstrated that the liver receptor homolog-1 (LRH-1), another nuclear receptor, regulates breast cancer cell proliferation and promotes motility and invasion. To determine the mechanisms of LRH-1 action in breast cancer, we performed gene expression microarray analysis following RNA interference for LRH-1. Interestingly, gene ontology (GO) category enrichment analysis of LRH-1–regulated genes identified oestrogen-responsive genes as the most highly enriched GO categories. Remarkably, chromatin immunoprecipitation coupled to massively parallel sequencing (ChIP-seq) to identify genomic targets of LRH-1 showed LRH-1 binding at many ERα binding sites. Analysis of select binding sites confirmed regulation of ERα−regulated genes by LRH-1 through binding to oestrogen response elements, as exemplified by the TFF1/pS2 gene. Finally, LRH-1 overexpression stimulated ERα recruitment, while LRH-1 knockdown reduced ERα recruitment to ERα binding sites. Taken together, our findings establish a key role for LRH-1 in the regulation of ERα target genes in breast cancer cells and identify a mechanism in which co-operative binding of LRH-1 and ERα at oestrogen response elements controls the expression of oestrogen-responsive genes.

Background On average, 21% of women in the USA treated with Breast Conserving Surgery (BCS) undergo a second operation because of close positive margins. Tumor identification with fluorescence imaging could improve positive margin rates through demarcating location, size, and invasiveness of tumors. We investigated the technique’s diagnostic accuracy in detecting tumors during BCS using intravenous indocyanine green (ICG) and a custom-built fluorescence camera system. Methods In this single-center prospective clinical study, 40 recruited BCS patients were sub-categorized into two cohorts. In the first ‘enhanced permeability and retention’ (EPR) cohort, 0.25 mg/kg ICG was injected ~ 25 min prior to tumor excision, and in the second ‘angiography’ cohort, ~ 5 min prior to tumor excision. Subsequently, an in-house imaging system was used to image the tumor in situ prior to resection, ex vivo following resection, the resection bed, and during grossing in the histopathology laboratory to compare the technique’s diagnostic accuracy between the cohorts. Results The two cohorts were matched in patient and tumor characteristics. The majority of patients had invasive ductal carcinoma with concomitant ductal carcinoma in situ. Tumor-to-background ratio (TBR) in the angiography cohort was superior to the EPR cohort (TBR = 3.18 ± 1.74 vs 2.10 ± 0.92 respectively, p = 0.023). Tumor detection reached sensitivity and specificity scores of 0.82 and 0.93 for the angiography cohort and 0.66 and 0.90 for the EPR cohort, respectively (p = 0.1051 and p = 0.9099). Discussion ICG administration timing during the angiography phase compared with the EPR phase improved TBR and diagnostic accuracy. Future work will focus on image pattern analysis and adaptation of the camera system to targeting fluorophores specific to breast cancer.

Introduction Conventional methods for axillary sentinel lymph node biopsy (SLNB) are fraught with complications such as allergic reactions, skin tattooing, radiation, and limitations on infrastructure. A novel technique has been developed for lymphatic mapping utilizing fluorescence imaging. This meta-analysis aims to compare the gold standard blue dye and radioisotope (BD-RI) technique with fluorescence-guided SLNB using indocyanine green (ICG). Methods This study was registered with PROSPERO (CRD42019129224). The MEDLINE, EMBASE, Scopus, and Web of Science databases were searched using the Medical Subject Heading (MESH) terms ‘Surgery’ AND ‘Lymph node’ AND ‘Near infrared fluorescence’ AND ‘Indocyanine green’. Studies containing raw data on the sentinel node identification rate in breast cancer surgery were included. A heterogeneity test (using Cochran’s Q) determined the use of fixed- or random-effects models for pooled odds ratios (OR). Results Overall, 1748 studies were screened, of which 10 met the inclusion criteria for meta-analysis. ICG was equivalent to radioisotope (RI) at sentinel node identification (OR 2.58, 95% confidence interval [CI] 0.35–19.08, p < 0.05) but superior to blue dye (BD) (OR 9.07, 95% CI 6.73–12.23, p < 0.05). Furthermore, ICG was superior to the gold standard BD-RI technique (OR 4.22, 95% CI 2.17–8.20, p < 0.001). Conclusion Fluorescence imaging for axillary sentinel node identification with ICG is equivalent to the single technique using RI, and superior to the dual technique (RI-BD) and single technique with BD. Hospitals using RI and/or BD could consider changing their practice to ICG given the comparable efficacy and improved safety profile, as well as the lesser burden on hospital infrastructure.

tion options with patients, irrespective of whether they are available locally. 6 Fifty three per cent of women having surgery for breast cancer will undergo mastectomy (box 1). 7 8 In the UK and United States, bilateral mastectomy is increasingly being used for risk reduction in BRCA carriers, for those with a high risk of developing breast cancer (lifetime risk of 30%), or as a planned management strategy for unilateral cancer (fig 1, bmj.com). 9-15 In general, bilateral mastectomy is associated with a higher rate of breast reconstruction. A recent Cochrane review showed that bilateral prophylactic (risk reduction) mastectomy reduced the incidence of, and death from, breast cancer, but it highlighted that more rigorous prospective studies are needed to assess absolute risk reduction. 16 The review also found that although contralateral prophylactic (risk reduction) mastectomy decreases the incidence of cancer in the contralateral breast, it is unclear whether, and for whom, this practice improves survival. 16 How is a mastectomy performed?When performing a mastectomy, the anatomical (oncological) plane between breast tissue and subcutaneous fat needs to be identified. It is, however, impossible to remove all breast tissue because the oncological plane is not uniform throughout the breast. A standard (simple) mastectomy removes the breast skin envelope, but a skin sparing mastectomy preserves the breast skin envelope Breast cancer is the most common cancer in women, with almost 1.38 million new cases a year worldwide; it accounts for 23% of all cancers and 14% of deaths from cancer. 1 However, mortality from breast cancer is d eclining-increasing numbers of women are long term survivors (>5 years) (currently 549 000 in the United K ingdom). 2 3 Surgery remains a mainstay of treatment, either breast conservation or mastectomy, but any breast surgery can greatly alter breast aesthetics and body image.Breast reconstruction restores breast symmetry after a mastectomy by creating a breast mound, similar in size, shape, contour, and "out of bra position" to the contralateral breast. In England and Wales in 2002, about 10% of women had immediate breast reconstruction; by 2009 this had risen to 21%. 4 Post-mastectomy breast reconstruction is associated with improved body image, quality of life, self confidence, and wellbeing. 5 In this review, we outline the indications for breast reconstruction along with the timing and techniques available to patients after mastectomy. What is post-mastectomy breast reconstruction?Breast reconstruction is a surgical procedure that restores shape to the breast after mastectomy. Although it will not re-create the exact look and feel of a natural breast, it aims to create a breast mound contour similar to that before mastectomy. When, and to whom, should breast reconstruction be offered?In 2009 the National Institute for Health and Clinical Excellence (NICE) revised guidance on improving breast cancer outcomes. It recommended discussing immediate reconstruction with all patients ha...