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AIM: There has been an increased focus on regulating cell function with Rho family GTPases, including proliferation, migration/invasion, polarity, and adhesion. Due to the challenges involved in targeting Rho family GTPases directly, it may be more effective to target their regulators, such as Rho GTPase-activating protein 1 (ARHGAP1). This present research was performed to define the clinical significance of ARHGAP1 expression, as well as its regulatory mechanisms in hepatocellular carcinoma. METHODS: ARHGAP1 and miR-101-3p expression of liver cancer patients, and their relevance with clinicopathological characteristics and prognosis were analyzed by the Cancer Genome Atlas sequencing data, and verified using samples of hepatocellular carcinoma patients. The interactions between miR-101-3p and ARHGAP1 or circPIP5K1A were validated by bioinformatic analyses, as well as confirmed by quantitative reverse transcription polymerase chain reaction, western blotting, and dual-luciferase reporter analysis. Plate clonality assays, cell adhesion and migration experiments, and proliferation experiments were used for assessing the participation of the circPIP5K1A/miR-101-3p/ARHGAP1 pathway in cell proliferation and motility. RESULTS: Elevated ARHGAP1 and reduced miR-101-3p expression are related to poorer survival. MiR-101-3p targets ARHGAP1 to suppress hepatocellular carcinoma cell colony formation and invasion, whereas miR-101-3p inhibitor reverses liver cancer proliferation and metastasis suppression caused by ARHGAP1 knockdown. In addition, circPIP5K1A, which is mainly distributed in the cytosol, showed carcinogenic effects by sponging miR-101-3p, thus regulating ARHGAP1 expression. CONCLUSIONS: ARHGAP1 serves as an oncogenic gene in liver cancer, and the expression thereof is regulated by circPIP5K1A through sponging miR-101-3p.
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OBJECTIVES: To compare the diagnostic efficacies of B-mode ultrasound (US), strain elastography (SE), contrast-enhanced ultrasound (CEUS) and the combination of these modalities for breast lesions <1 cm in size. METHODS: Between January 2013 and October 2015, 203 inpatients with 209 sub-centimetre breast lesions categorised as BI-RADS-US (Breast Imaging Reporting and Data System for Ultrasound) 3-5 were included. US, SE and CEUS were performed to evaluate each lesion. The diagnostic performances of different ultrasonic modalities were compared. The diagnostic efficacies of BI-RADS-US and our re-rating systems were also compared. The pathology findings were used as the reference standard. RESULTS: The specificities of US, SE and CEUS for tumour differentiation were 17.4 %, 56.2 % and 86.0 %, respectively (P < 0.05); and the sensitivities were 100 %, 93.2 % and 93.2 % for US, SE and CEUS, respectively (P < 0.05). The area under the curve (AUC) of the receiver operating characteristic (ROC) curve was 0.867 for original BI-RADS-US, 0.882 for BI-RADS-US combined with only SE, 0.953 for BI-RADS-US combined with only CEUS and 0.924 for BI-RADS-US combined with both SE and CEUS. The best combination was BI-RADS-US combined with only CEUS. CONCLUSIONS: Evaluating sub-centimetre breast lesions with SE and CEUS could increase the diagnostic specificity while retaining high sensitivity compared with B-mode ultrasound. KEY POINTS: ⢠Evaluating breast lesions with SE and CEUS could increase the diagnostic specificity ⢠SE and CEUS offer alternatives to biopsy and possibly allow shorter-interval follow-ups ⢠BI-RADS-US combined with CEUS exhibited the best diagnostic performance.
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Neoplasias da Mama/diagnóstico por imagem , Técnicas de Imagem por Elasticidade/métodos , Ultrassonografia Mamária/métodos , Adolescente , Adulto , Idoso , Área Sob a Curva , Biópsia , Mama/diagnóstico por imagem , China , Meios de Contraste , Técnicas de Imagem por Elasticidade/normas , Feminino , Humanos , Pessoa de Meia-Idade , Imagem Multimodal/métodos , Imagem Multimodal/normas , Curva ROC , Sensibilidade e Especificidade , Ultrassonografia Mamária/normas , Adulto JovemRESUMO
Contrast-enhanced ultrasound (CEUS) plays a crucial role in cancer diagnosis. The use of ultrasound contrast agents (UCAs) is inevitable in CEUS. However, current applications of UCAs primarily focus on enhancing imaging quality of ultrasound contrast rather than serving as integrated platforms for both diagnosis and treatment in clinical settings. In this study, a novel UCA, termed NPs-DPPA(C3F8), is innovatively prepared using a combination of nanoprecipitation and ultrasound vibration methods. The DPPA lipid possesses inherent antiangiogenic and antitumor activities, and when combined with C3F8, it functions as a theranostic agent. Notably, the preparation of NPs-DPPA(C3F8) is straightforward, requiring only one hour from raw materials to the final product due to the use of a single material, DPPA. NPs-DPPA(C3F8) exhibits inherent antiangiogenic and biotherapeutic activities, effectively inhibiting triple-negative breast cancer (TNBC) angiogenesis and reducing VEGFA expression both in vitro and in vivo. Clinically, NPs-DPPA(C3F8) enables simultaneous real-time imaging, tumor assessment, and antitumor activity. Additionally, through ultrasound cavitation, NPs-DPPA(C3F8) can overcome the dense vascular walls to increase accumulation at the tumor site and facilitate internalization by tumor cells. The successful preparation of NPs-DPPA(C3F8) offers a novel approach for integrating clinical diagnosis and treatment of TNBC.
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Meios de Contraste , Nanopartículas , Ultrassonografia , Meios de Contraste/química , Feminino , Humanos , Animais , Linhagem Celular Tumoral , Camundongos , Ultrassonografia/métodos , Nanopartículas/química , Neoplasias de Mama Triplo Negativas/diagnóstico por imagem , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Neoplasias de Mama Triplo Negativas/terapia , Neoplasias da Mama/diagnóstico por imagem , Neoplasias da Mama/tratamento farmacológico , Neovascularização Patológica/diagnóstico por imagem , Neovascularização Patológica/tratamento farmacológico , Camundongos Nus , Nanomedicina Teranóstica/métodos , Camundongos Endogâmicos BALB C , Inibidores da Angiogênese/química , Inibidores da Angiogênese/farmacologiaRESUMO
Emerging evidence shows that the biomechanical environment is required to support cancer stem cells (CSCs), which play a crucial role in drug resistance. However, how mechanotransduction signals regulate CSCs and its clinical significance has remained unclear. Using clinical-practice ultrasound elastography for patients' lesions and atomic force microscopy for surgical samples, we reveal that increased matrix stiffness is associated with poor responses to neoadjuvant chemotherapy, worse prognosis, and CSC enrichment in patients with breast cancer. Mechanically, TAZ activated by biomechanics enhances CSC properties via phase separation with NANOG. TAZ-NANOG phase separation, which is dependent on acidic residues in the N-terminal activation domain of NANOG, promotes the transcription of SOX2 and OCT4. Therapeutically, targeting NANOG or TAZ reduces CSCs and enhances the chemosensitivity in vivo. Collectively, this study demonstrated that the phase separation of a pluripotency transcription factor links mechanical cues in the niche to the fate of CSCs.
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Neoplasias da Mama , Mecanotransdução Celular , Proteína Homeobox Nanog , Proteínas com Motivo de Ligação a PDZ com Coativador Transcricional , Feminino , Humanos , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Proteína Homeobox Nanog/genética , Células-Tronco Neoplásicas/patologia , Fatores de Transcrição/genética , Proteínas com Motivo de Ligação a PDZ com Coativador Transcricional/genética , Nicho de Células-TroncoRESUMO
Elastography ultrasound (EUS) imaging is a vital ultrasound imaging modality. The current use of EUS faces many challenges, such as vulnerability to subjective manipulation, echo signal attenuation, and unknown risks of elastic pressure in certain delicate tissues. The hardware requirement of EUS also hinders the trend of miniaturization of ultrasound equipment. Here we show a cost-efficient solution by designing a deep neural network to synthesize virtual EUS (V-EUS) from conventional B-mode images. A total of 4580 breast tumor cases were collected from 15 medical centers, including a main cohort with 2501 cases for model establishment, an external dataset with 1730 cases and a portable dataset with 349 cases for testing. In the task of differentiating benign and malignant breast tumors, there is no significant difference between V-EUS and real EUS on high-end ultrasound, while the diagnostic performance of pocket-sized ultrasound can be improved by about 5% after V-EUS is equipped.
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Neoplasias da Mama , Técnicas de Imagem por Elasticidade , Humanos , Feminino , Técnicas de Imagem por Elasticidade/métodos , Neoplasias da Mama/diagnóstico por imagem , Ultrassonografia , Endossonografia/métodos , Diagnóstico Diferencial , Sensibilidade e EspecificidadeRESUMO
Residual tumors after insufficient radiofrequency ablation (IRFA) shows accelerated progression and anti-PD-1 resistance. It is also reported that macrophages infiltrating into residual tumors leads to anti-PD-1 resistance. Elements of autophagy have been detected to conjugate LC3 to be increasingly expressed in residual tumors. The underlying mechanisms between LC3 and macrophages are aimed to be investigated, and explore further ways to enhance immunotherapy in treating residual tumors. In mice models and patients, macrophages demonstrate increased infiltration into residual tumors, especially surrounding the ablated zone. Single-cell transcriptome demonstrates enhancement of immunosuppression function in macrophages after IRFA. It is shown that macrophages engulf heat-treated cells through LC3-associated phagocytosis (LAP), enhance IL-4 mediated macrophage programming through the PI3Kγ/AKT pathway, and suppress T cell proliferation. Blockade of the PI3Kγ/AKT pathway enhances the antitumor activity of PD-1 blockades, inhibits malignant growth, and enhances survival in post-IRFA models. In conclusion, in mice models and patients, macrophages demonstrate increased infiltration around ablated zones in residual tumors. Blockade of the PI3Kγ/AKT pathway suppresses the growth of residual tumors in subcutaneous and orthotopic models. The results illustrate the translational potential of PI3Kγ inhibitors to enhance anti-PD-1 therapy for the treatment of residual tumors after IRFA.
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Carcinoma Hepatocelular , Neoplasias Hepáticas , Ablação por Radiofrequência , Animais , Humanos , Terapia de Imunossupressão , Camundongos , Fagocitose , Proteínas Proto-Oncogênicas c-akt , Ablação por Radiofrequência/métodosRESUMO
Purpose: To develop a risk stratification system that can predict axillary lymph node (LN) metastasis in invasive breast cancer based on the combination of shear wave elastography (SWE) and conventional ultrasound. Materials and Methods: A total of 619 participants pathologically diagnosed with invasive breast cancer underwent breast ultrasound examinations were recruited from a multicenter of 17 hospitals in China from August 2016 to August 2017. Conventional ultrasound and SWE features were compared between positive and negative LN metastasis groups. The regression equation, the weighting, and the counting methods were used to predict axillary LN metastasis. The sensitivity, specificity, and the areas under the receiver operating characteristic curve (AUC) were calculated. Results: A significant difference was found in the Breast Imaging Reporting and Data System (BI-RADS) category, the "stiff rim" sign, minimum elastic modulus of the internal tumor and peritumor region of 3 mm between positive and negative LN groups (p < 0.05 for all). There was no significant difference in the diagnostic performance of the regression equation, the weighting, and the counting methods (p > 0.05 for all). Using the counting method, a 0-4 grade risk stratification system based on the four characteristics was established, which yielded an AUC of 0.656 (95% CI, 0.617-0.693, p < 0.001), a sensitivity of 54.60% (95% CI, 46.9%-62.1%), and a specificity of 68.99% (95% CI, 64.5%-73.3%) in predicting axillary LN metastasis. Conclusion: A 0-4 grade risk stratification system was developed based on SWE characteristics and BI-RADS categories, and this system has the potential to predict axillary LN metastases in invasive breast cancer.
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Though radiofrequency ablation (RFA) is considered to be an effective treatment for hepatocellular carcinoma (HCC), but more than 30% of patients may suffer insufficient RFA (IRFA), which can promote more aggressive of the residual tumor. One possible method to counter this is to accurately identify the margin of the HCC. Colony-stimulating factor 1 receptor (CSF-1R) has been found to be restrictively expressed by tumor associated macrophages (TAMs) and monocytes which more prefer to locate at the boundary of HCC. Using biotinylation method, we developed a CSF-1R-conjugated nanobubble CSF-1R (NBCSF-1R) using a thin-film hydration method for margin detection of HCC. CSF-1R expression was higher in macrophages than in HCC cell lines. Furthermore, immunofluorescence showed that CSF-1R were largely located in the margin of xenograft tumor and IFRA models. In vitro, NBCSF-1R was stable and provided a clear ultrasound image even after being stored for 6 months. In co-culture, NBCSF-1R adhered to macrophages significantly better than HCC cells (p = 0.05). In in vivo contrast-enhanced ultrasound imaging, the washout half-time of the NBCSF-1R was significantly greater than that of NBCTRL and Sonovue® (p = 0.05). The signal intensity of the tumor periphery was higher than the tumor center or non-tumor region after NBCSF-1R injection. Taken together, NBCSF-1R may potentially be used as a non-invasive diagnostic modality in the margin detection of HCC, thereby improving the efficiency of RFA. This platform may also serve as a complement method to detect residual HCC after RFA; and may also be used for targeted delivery of therapeutic drugs or genes.
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BACKGROUND: RNA helicases have various essential functions in basically all aspects of RNA metabolism, not only unwinding RNA but also disturbing the interaction of RNA with proteins. Recently, RNA helicases have been considered potential targets in cancers. So far, there has been no detailed investigation of the biological functions of RNA helicase DHX37 in cancers. OBJECTIVE: We aim to identify the prognostic value of DHX37 associated with tumor microenvironments in cancers. METHODS: DHX37 expression was examined via the Oncomine database and Tumor Immune Estimation Resource (TIMER). We explored the prognostic role of DHX37 in cancers across various databases. Coexpression genes, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG), and fundamental regulators were performed via LinkedOmics. Confirming the prognostic value of DHX37 in liver hepatocellular carcinoma (LIHC) and lung adenocarcinoma (LUAD), we explored the role of DHX37 in infiltrated lymphocytes in cancers using the Gene Expression Profiling Interactive Analysis (GEPIA) and TIMER databases. RESULTS: Through GO and KEGG analyses, expression of DHX37 was also correlated with complex function-specific networks involving the ribosome and RNA metabolic signaling pathways. In LIHC and LUAD, DHX37 expression showed significant positive correlations with markers of Tregs, myeloid-derived suppressor cells (MDSCs), and T cell exhaustion, contributing to immune tolerance. CONCLUSION: These results indicate that DHX37 can serve as a prognostic biomarker in LIHC and LUAD while having an important role in immune tolerance by activating the function of Tregs, MDSC, and T cell exhaustion.
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Adenocarcinoma de Pulmão/mortalidade , Biomarcadores Tumorais/metabolismo , Carcinoma Hepatocelular/mortalidade , Neoplasias Hepáticas/mortalidade , Neoplasias Pulmonares/mortalidade , RNA Helicases/metabolismo , Adenocarcinoma de Pulmão/genética , Adenocarcinoma de Pulmão/imunologia , Adenocarcinoma de Pulmão/patologia , Biomarcadores Tumorais/análise , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/imunologia , Carcinoma Hepatocelular/patologia , Conjuntos de Dados como Assunto , Feminino , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica/imunologia , Humanos , Estimativa de Kaplan-Meier , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/imunologia , Neoplasias Hepáticas/patologia , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/imunologia , Neoplasias Pulmonares/patologia , Linfócitos do Interstício Tumoral/imunologia , Masculino , Células Supressoras Mieloides/imunologia , Prognóstico , RNA Helicases/análise , Transdução de Sinais/genética , Transdução de Sinais/imunologia , Linfócitos T Reguladores/imunologia , Microambiente Tumoral/genética , Microambiente Tumoral/imunologiaRESUMO
Repair of DNA double-strand breaks (DSBs) is essential for genome integrity, and is accompanied by transcriptional repression at the DSB regions. However, the mechanisms how DNA repair induces transcriptional inhibition remain elusive. Here, it is identified that BRD7 participates in DNA damage response (DDR) and is recruited to the damaged chromatin via ATM signaling. Mechanistically, BRD7 joins the polycomb repressive complex 2 (PRC2), the nucleosome remodeling and histone deacetylation (NuRD) complex at the damaged DNA and recruits E3 ubiquitin ligase RNF168 to the DSBs. Furthermore, ATM-mediated BRD7 phosphorylation is required for recruitment of the PRC2 complex, NuRD complex, DSB sensor complex MRE11-RAD50-NBS1 (MRN), and RNF168 to the active transcription sites at DSBs, resulting in transcriptional repression and DNA repair. Moreover, BRD7 deficiency sensitizes cancer cells to PARP inhibition. Collectively, BRD7 is crucial for DNA repair and DDR-mediated transcription repression, which may serve as a therapeutic target. The findings identify the missing link between DNA repair and transcription regulation that maintains genome integrity.
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Despite the functions of anti-PD-1 antibodies as immune checkpoint regulators, less than 30% of patients exhibit durable therapeutic responses to anti-PD-1 antibodies. Studies have shown that insufficient infiltration of immune cells might limit the outcome of anti-PD-1 therapy. Therefore, we synthesized an immune cell-recruiting liposomal system (FN-nps) to improve this therapeutic strategy. The FN-nps could generate cell debris and expose heat shock protein 70, which could recruit immune cells to tumor sites to assist in anti-PD-1 treatment. In vivo experiments revealed that the FN-nps could assist in anti-PD-1 therapy by increasing the number of lymphocytes in the peripheral blood and tumor site by generating tumor antigens, and this effect was accompanied by an increase in cytokine expression. The number of CTLs increased and mRNA expression levels of cytokines were regulated when the FN-nps were combined with anti-PD-1 therapy. The revealed properties of the liposomal system make it highly promising for assisting in anti-PD-1 antibody immunotherapy in different cancers.
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Anticorpos Monoclonais/metabolismo , Lipossomos/química , Receptor de Morte Celular Programada 1/imunologia , Animais , Anticorpos Monoclonais/química , Anticorpos Monoclonais/uso terapêutico , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Citocinas/sangue , Feminino , Proteínas de Choque Térmico HSP72/metabolismo , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Microscopia de Fluorescência , Nanopartículas/química , Nanopartículas/metabolismo , Nanopartículas/toxicidade , Neoplasias/diagnóstico por imagem , Neoplasias/tratamento farmacológico , Neoplasias/mortalidade , Taxa de Sobrevida , Linfócitos T Citotóxicos/citologia , Linfócitos T Citotóxicos/imunologia , Distribuição Tecidual , Transplante Heterólogo , UltrassonografiaRESUMO
The aim of the study was to develop a scoring model incorporating the Breast Imaging Reporting and Data System (BI-RADS) and the contrast-enhanced ultrasound (CEUS) scoring system to differentiate between malignant and benign breast lesions. A total of 524 solid breast masses in 490 consecutive patients were evaluated with conventional US and CEUS in this prospective study. Each lesion was scored according to BI-RADS, CEUS, and CEUS-rerated BI-RADS. The diagnostic specificity, sensitivity and accuracy of BI-RADS were 77.9%, 88.9% and 84.0%, respectively, and the area under the receiver operating characteristic curve was 0.834. The corresponding values for rerated BI-RADS were 82.1%, 96.9%, 90.3% and 0.895. The area under the receiver operating characteristic curve of BI-RADS alone was significantly smaller than that of CEUS and the rerated BI-RADS (p = 0.008 compared with CEUS, p = 0.002 compared with rerated BI-RADS). This study indicates that rerating BI-RADS with the CEUS scoring system improves its diagnostic accuracy.
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Neoplasias da Mama/diagnóstico por imagem , Meios de Contraste , Aumento da Imagem/métodos , Sistemas de Informação em Radiologia , Ultrassonografia Mamária/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Mama/diagnóstico por imagem , China , Diagnóstico Diferencial , Feminino , Humanos , Pessoa de Meia-Idade , Estudos Prospectivos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Adulto JovemRESUMO
BACKGROUND: There is an unmet need for specific and sensitive imaging techniques to assess the efficacy of breast cancer therapy, particularly Her-2-expressing cancers. Ultrasonic microbubbles are being developed for use as diagnostic and therapeutic tools. However, nanobubbles circulate longer, are smaller, and diffuse into extravascular tissue to specifically bind target molecules. Here, we characterize a novel Herceptin-conjugated nanobubble for use against Her-2-expressing tumors. METHODS: Phospholipid-shelled nanobubbles conjugated with Herceptin (NBs-Her) were fabricated using a thin-film hydration method and characterized in vitro in breast cancer cell lines and in vivo in a mouse model. RESULTS: The average size of the unconjugated nanobubbles (NBs-Blank) and NBs-Her was 447.1 ± 18.4 and 613.0 ± 25.4 nm, respectively. In cell culture, the NBs-Her adhered to Her-2-positive cells significantly better than to Her-2-negative cells (p < 0.05). In vivo, the peak intensity and the half-time to washout of the NBs-Her were significantly greater than those of the NBs-Blank (p < 0.05). In addition, contrast-enhanced ultrasound imaging quality was improved through the use of the NBs-Her. The nanobubbles were able to penetrate into tumor tissue to allow extravascular imaging, but did not penetrate normal skeletal muscle. CONCLUSIONS: The Herceptin-conjugated nanobubble had many properties that made it useful for in vivo imaging, including longer circulation time and better tumor selectivity. This platform may be able to provide targeted delivery of therapeutic drugs or genes.
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Neoplasias da Mama/diagnóstico por imagem , Meios de Contraste/química , Meios de Contraste/farmacocinética , Receptor ErbB-2/metabolismo , Trastuzumab/administração & dosagem , Animais , Neoplasias da Mama/metabolismo , Linhagem Celular Tumoral , Feminino , Humanos , Camundongos Nus , Microbolhas , Nanoestruturas/química , Fosfolipídeos/química , Trastuzumab/química , Trastuzumab/farmacocinética , Ultrassonografia Mamária , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
PURPOSE: To evaluate the additive diagnostic performance of ultrasound elastography (UE) to ultrasound (US) with the 2003 or 2013 Breast Imaging Reporting and Data System (BI-RADS)-US classification systems for the differentiation of benign and malignant breast lesions. METHODS: From June 2010 to December 2012, 738 women with 770 breast lesions were recruited into this retrospective study. Breast lesions were evaluated separately by US, UE, and both. US assessment was based on the 2003 or 2013 BI-RADS-US, and UE assessment was based on a previously reported 5-point scale. Diagnostic performance of US, UE, and both was compared. RESULTS: Before category 4 lesions were subdivided, the area under the receiver operating characteristic curve (AUC) for US, UE, and both were, respectively, 0.735, 0.877, 0.878 (P < .01). When subcategories of 4 lesions were considered, the AUC for US, UE, and both were, respectively, 0.865, 0.877, and 0.883 (P > .05). Adding UE to analysis of 4A lesions can decrease the percentages of malignancy to 2.56%. CONCLUSION: When the 2003 BI-RADS was considered, UE could give US some help in differentiating breast lesions. However, when the 2013 BI-RADS was considered, UE gave little help to US, although it reduced unnecessary biopsies of benign category 4A lesions.
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Neoplasias da Mama/diagnóstico por imagem , Técnicas de Imagem por Elasticidade/métodos , Ultrassonografia Mamária/métodos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Área Sob a Curva , Feminino , Humanos , Pessoa de Meia-Idade , Curva ROC , Estudos Retrospectivos , Sensibilidade e Especificidade , Adulto JovemRESUMO
Small interfering RNA (siRNA) technology is a powerful tool in biomedical research and holds great potential for RNA interference-based therapies for HIV, hepatitis and cancer. However, the absence of a safe and efficient method for the delivery of siRNA has become a bottleneck for their development. Nanocrystallized hydroxyapatite (nHAP) appears to be an optimal candidate non-viral gene vector for several reasons, including its good biocompatibility and ease of production, however, nHAP microemulsions cannot remain monodispersed for long periods of time. Due to their high surface energy, nHAP particles gradually aggregate into large ones that are difficult for the cell to take up. To overcome this we modified nHAP with polyethylenimine (PEI) to generate a compound (MnHAP) with a tight size-distribution of <200 nm. The positive surface potential of MnHAP inhibited particle aggregation and thus made it easier to conjugate more siRNA. The transfection efficiency of MnHAP/fluorescent FAM-labeled siRNA complex was tested using flow cytometry, and the transfected cells were observed using fluorescence microscopy. The cytotoxicity of MnHAP/siRNA complexes to the human liver cancer cell line BEL-7402 was assessed in vitro by a formazan dye assay. Our results show that the in vitro transfection efficiency of MnHAP/siRNA was equivalent to that of the commercially available transfection agent Lipofectamine® 2000, but with decreased cytotoxicity. The MnHAP nanoparticles were also able to deliver siRNA for silencing of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) in BEL-7402 cells, which supports that MnHAP might be a promising non-viral vector for biomedical research and gene delivery.