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BACKGROUND: An accurate status determination of breast cancer biomarkers (ER, PR, HER2, Ki67) is crucial for guiding patient management. The "gold standard" for assessing these biomarkers in FFPE tissue is IHC, which faces challenges in standardization and exhibits substantial variability. In this study, we compare the concordance of a new commercial RT-qPCR kit with IHC in determining BC biomarker status. METHODS: The performance was evaluated using 634 FFPE specimens, which underwent histological analysis in accordance with standard of care methods. HER2 2+ tumors were referred to ISH testing. An immunoreactive score of ≥2/12 was considered positive for ER/PR and 20% staining was used as a cut-off for Ki67 high/low score. RT-qPCR and results calling were performed according to the manufacturer's instructions. RESULTS: High concordance with IHC was seen for all markers (93.2% for ER, 87.1% for PR, 93.9% for HER2, 77.9% for Ki67 and 80.1% for proliferative signature (assessed against Ki67 IHC)). CONCLUSIONS: By assessing the concordance with the results obtained through IHC, we sought to demonstrate the reliability and utility of the kit for precise BC subtyping. Our findings suggest that the kit provides a highly precise and accurate quantitative assessment of BC biomarkers.
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Glycosylation is a prominent posttranslational modification, and alterations in glycosylation are a hallmark of cancer. Glycan-binding receptors, primarily expressed on immune cells, play a central role in glycan recognition and immune response. Here, we used the recombinant C-type glycan-binding receptors CD301, Langerin, SRCL, LSECtin, and DC-SIGNR to recognize their ligands on tissue microarrays (TMA) of a large cohort (n = 1859) of invasive breast cancer of different histopathological types to systematically determine the relevance of altered glycosylation in breast cancer. Staining frequencies of cancer cells were quantified in an unbiased manner by a computer-based algorithm. CD301 showed the highest overall staining frequency (40%), followed by LSECtin (16%), Langerin (4%) and DC-SIGNR (0.5%). By Kaplan-Meier analyses, we identified LSECtin and CD301 as prognostic markers in different breast cancer subtypes. Positivity for LSECtin was associated with inferior disease-free survival in all cases, particularly in estrogen receptor positive (ER+) breast cancer of higher histological grade. In triple negative breast cancer, positivity for CD301 correlated with a worse prognosis. Based on public RNA single-cell sequencing data of human breast cancer infiltrating immune cells, we found CLEC10A (CD301) and CLEC4G (LSECtin) exclusively expressed in distinct subpopulations, particularly in dendritic cells and macrophages, indicating that specific changes in glycosylation may play a significant role in breast cancer immune response and progression.
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Neoplasias da Mama , Humanos , Feminino , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Prognóstico , Lectinas Tipo C/genética , Ligantes , Polissacarídeos , Imunidade InataRESUMO
Gene expression signatures refer to patterns of gene activities and are used to classify different types of cancer, determine prognosis, and guide treatment decisions. Advancements in high-throughput technology and machine learning have led to improvements to predict a patient's prognosis for different cancer phenotypes. However, computational methods for analyzing signatures have not been used to evaluate their prognostic power. Contention remains on the utility of gene expression signatures for prognosis. The prevalent approaches include random signatures, expert knowledge, and machine learning to construct an improved signature. We unify these approaches to evaluate their prognostic power. Re-evaluation of publicly available gene-expression data from 8 databases with 9 machine-learning models revealed previously unreported results. Gene-expression signatures are confirmed to be useful in predicting a patient's prognosis. Convergent evidence from [Formula: see text] 10,000 signatures implicates a maximum prognostic power. By calculating the concordance index, which measures how well patients with different prognoses can be discriminated, we show that a signature can correctly discriminate patients' prognoses no more than 80% of the time. Additionally, we show that more than 50% of the potentially available information is still missing at this value. We surmise that an accurate prognosis must incorporate molecular, clinical, histological, and other complementary factors.
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Neoplasias da Mama , Humanos , Feminino , Neoplasias da Mama/diagnóstico , Neoplasias da Mama/genética , Neoplasias da Mama/tratamento farmacológico , Prognóstico , Transcriptoma , Bases de Dados Factuais , Aprendizado de Máquina , Perfilação da Expressão GênicaRESUMO
Primary squamous cell carcinoma or squamous intraepithelial lesion of the fallopian tube is a very rare finding with only a small number of cases worldwide. We describe the case of a 51-year-old woman, undergoing an abdominal hysterectomy after the diagnosis of an HPV-associated invasive squamous cell carcinoma of the uterine cervix with the unexpected detection of an HPV16-positive high-grade squamous intraepithelial lesion of the fimbria of the right fallopian tube in the resection specimen. The finding of an isolated, HPV-associated squamous intraepithelial lesion in the fallopian tube raises the question of a de novo development in this body compartment (after exclusion of a continuous metastatic spread from the uterine cervix) by taking a virus-associated field effect into account and should encourage the inclusion of this possibility when examining the fallopian tube in a routine setting.
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CONTEXT.: Low-grade fibromatosis-like metaplastic carcinoma (FLMC) is a very rare subtype of triple-negative metaplastic (spindle cell) breast carcinoma. It is characterized by the proliferation of spindle cells closely resembling fibromatosis, which represents a benign fibroblastic/myofibroblastic breast proliferation. Unlike most triple-negative and basal-like breast cancers, FLMC has a very low potential for metastases, but demonstrates frequent local recurrences. OBJECTIVE.: To genetically characterize FLMC. DESIGN.: To this end, we analyzed 7 cases by targeted next-generation sequencing for 315 cancer-related genes and performed comparative microarray copy number analysis in 5 of these cases. RESULTS.: All cases shared TERT alterations (6 patients with recurrent c.-124C>T TERT promoter mutation and 1 patient with copy number gain encompassing the TERT locus), had oncogenic PIK3CA/PIK3R1 mutations (activation of the PI3K/AKT/mTOR pathway), and lacked mutations in TP53. TERT was overexpressed in all FLMCs. CDKN2A/B loss or mutation was observed in 4 of 7 cases (57%). Furthermore, tumors displayed chromosomal stability, with only few copy number variations and a low tumor mutational burden. CONCLUSIONS: We conclude that FLMCs typically show the recurrent TERT promoter mutation c.-124C>T, activation of the PI3K/AKT/mTOR pathway, low genomic instability, and wild-type TP53. In conjunction with previous data of metaplastic (spindle cell) carcinoma with and without fibromatosis-like morphology, FLMC is most likely distinguished by TERT promoter mutation. Thus, our data support the notion of a distinct subgroup within low-grade metaplastic breast cancer with spindle cell morphology and associated TERT mutations.
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Neoplasias da Mama , Carcinoma , Fibroma , Telomerase , Humanos , Feminino , Variações do Número de Cópias de DNA , Proteínas Proto-Oncogênicas c-akt/genética , Fosfatidilinositol 3-Quinases/genética , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Carcinoma/patologia , Serina-Treonina Quinases TOR/genética , Mutação , Fibroma/genética , Fibroma/patologia , Telomerase/genéticaRESUMO
The diagnosis of breast cancer-including determination of prognosis and prediction-has been traditionally based on clinical and pathological characteristics such as tumor size, nodal status, and tumor grade. The decision-making process has been expanded by the recent introduction of molecular signatures. These signatures, however, have not reached the highest levels of evidence thus far. Yet they have been brought to clinical practice based on statistical significance in prospective as well as retrospective studies. Intriguingly, it has also been reported that most random sets of genes are significantly associated with disease outcome. These facts raise two highly relevant questions: What information gain do these signatures procure? How can one find a signature that is substantially better than a random set of genes? Our study addresses these questions. To address the latter question, we present a hybrid signature that joins the traditional approach with the molecular one by combining the Nottingham Prognostic Index with gene expressions in a data-driven fashion. To address the issue of information gain, we perform careful statistical analysis and comparison of the hybrid signature, gene expression lists of two commercially available tests as well as signatures selected at random, and introduce the Signature Skill Score-a simple measure to assess improvement on random signatures. Despite being based on in silico data, our research is designed to be useful for the decision-making process of oncologists and strongly supports association of random signatures with outcome. Although our study shows that none of these signatures can be considered as the main candidate for providing prognostic information, it also demonstrates that both the hybrid signature and the gene expression list of the OncotypeDx signature identify patients who may not require adjuvant chemotherapy. More importantly, we show that combining signatures substantially improves the identification of patients who do not need adjuvant chemotherapy.
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Algoritmos , Neoplasias da Mama/diagnóstico , Área Sob a Curva , Neoplasias da Mama/genética , Árvores de Decisões , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Prognóstico , Modelos de Riscos Proporcionais , Curva ROCRESUMO
Breast cancer is a heterogeneous disease representing a number of different histopathologic and molecular types which should be taken into consideration if prognostic or predictive models are to be developed. The aim of the present study was to demonstrate the validity of the long-known Nottingham prognostic index (NPI) in a large retrospective study (n = 6654 women with a first primary unilateral and unifocal invasive breast cancer diagnosed and treated between April 1996 and October 2018; median follow-up time of breast cancer cases was 15.5 years [14.9-16.8]) from a single pathological institution. Furthermore, it was intended to develop an even superior risk stratification model considering an additional variable, namely the patient's age at the time of diagnosis. Heterogeneity of these cases was addressed by focusing on estrogen receptor-positive as well as Her2-negative cases and taking the WHO-defined different tumor types into account. Calculating progression free survival Cox-regression and CART-analysis revealed significantly superior iAUC as well as concordance values in comparison to the NPI based stratification, leading to an alternative, namely the Altona prognostic index (API). The importance of the histopathological tumor type was corroborated by the fact that when calculated separately and in contrast to the most frequent so-called "No Special Type" (NST) carcinomas, neither NPI nor API could show valid prognostic stratification.
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BACKGROUND: Desmoid type fibromatoses has proven to be a diagnostic and therapeutic challenge, as they often appear primarily as a carcinoma of the breast with a high recurrence risk. PATIENTS: A digital archive search was performed for the period from 2009 to the end of 2018. Inclusion criteria consisted of histological examination of at least the surgical specimen in the reference pathology department and at least a second opinion diagnosis in the reference radiology department. RESULTS: A total of 14 women and 1 man underwent surgery on desmoid type fibromatosis of the breast. The average patient age was 49 years (range: 22-72 years). The mean tumor size was 2.2 cm (range: 0.8-4.2 cm). The tumor was detectable in mammography in 12 out of 13 patients and in all 15 patients in sonography. MRI was performed preoperatively in 6 patients; in all of the patients, the tumor was visualized with inhomogeneous contrast enhancement. In the imaging procedures, all desmoid type fibromatoses were classified as suspicious. Performing the core biopsy, preoperative histology confirmed desmoid fibromatosis in 12 out of 15 patients. Nuclear stain for ß-catenin was positive in 7 out of 10 patients. Negative staining was found for AE1/A3 in 10 out of 10 and CD34 in 12 out of 12 patients. In all of the patients, a single-stage operation without the detection of border-forming tumor margins was performed. The follow-up interval ranged from 16 to 96 months (mean: 44.86 months, median: 43 months). In this follow-up period, no patient was diagnosed with desmoid tumor recurrence. CONCLUSION: In imaging, desmoid type fibromatosis of the breast has typical malignancy-related criteria. Extensive preoperative diagnostics enable the planning of complete primary excision of the lesion and reduce the recurrence risk.
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BACKGROUND: Ligands of the C-type lectin CLEC10A such as Tn and sialyl-Tn representing early intermediates of O-glycosylation are hallmarks of many human malignancies. A variety of regulatory mechanisms underlying their expression are being discussed. METHODS: CLEC10A ligands were detected in various tissues and cells using the recombinant glycan-binding domain of CLEC10A. In normal breast and endometrium, presence of ligands was correlated to the female cycle. Estrogen- and stress dependent induction of CLEC10A ligands was analyzed in MCF7 and T47D cells exposed to 4-hydroxy-tamoxifen (Tam), zeocin and hydrogen peroxide. The expression and localization of CLEC10A ligands was analyzed by Western blot and immunofluorescence. In breast cancer patients CLEC10A ligand expression and survival was correlated by Kaplan-Meyer analysis. RESULT: We observed binding of CLEC10A in normal endometrial and breast tissues during the late phase of the female hormonal cycle suggesting a suppressive effect of female sex hormones on CLEC10A ligand expression. Accordingly, CLEC10A ligands were induced in MCF7- and T47D breast cancer cells after Tam treatment and accumulated on the cell surface and in the endosomal/lysosomal compartment. Phagocytosis experiments indicate that macrophages preferentially internalize CLEC10A ligands coated beads and Tam treated MCF7 cells. CLEC10A ligands were also expressed after the addition of zeocin and hydrogen-peroxide. Each substance induced the production of ROS indicating reactive oxygen species as a unifying mechanism of CLEC10A ligand induction. Mechanistically, increased expression of GalNAc-transferase 6 (GalNT6) and translocation of GalNT2 and GalNT6 from cis- towards trans-Golgi compartment was observed, while protein levels of COSMC and T-synthase remained unaffected. In breast cancer patients, positivity for CLEC10A staining in tumor tissues was associated with improved outcome and survival. CONCLUSION: CLEC10A ligands are inducible by hormone depletion, 4-hydroxy-tamoxifen and agents inducing DNA damage and oxidative stress. Our results indicate that CLEC10A acts as a receptor for damaged and dead cells and may play an important role in the uptake of cell debris by macrophages and dendritic cells.
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Antineoplásicos/farmacologia , Neoplasias da Mama/tratamento farmacológico , Lectinas Tipo C/antagonistas & inibidores , Polissacarídeos/análise , Tamoxifeno/análogos & derivados , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Dano ao DNA , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Células HEK293 , Humanos , Lectinas Tipo C/metabolismo , Ligantes , Células MCF-7 , Estresse Oxidativo/efeitos dos fármacos , Proteínas Recombinantes/metabolismo , Transdução de Sinais , Tamoxifeno/farmacologiaRESUMO
Here, we present an optically optimized system for static ultramicroscopy imaging technique. The unit for generating an ultra-thin light sheet employs aspheric and meso-optical elements (meso-aspheric system). An analytical as well as an experimental comparison between the light sheet produced by the standard system (using a rectangular slit aperture and one cylindrical lens) and the one produced by our latest optimized system, which converts a symmetrical Gaussian beam into an ultra-thin light sheet is presented. Using the new light sheet in combination with our objective equipped with a modulator unit to compensate the refractive index mismatch between air and mediums with indices of 1.45-1.56, we present high resolution images of various biological samples that were chemically cleared using different methods. They demonstrate a marked improvement in quality, contrast and resolution.
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BACKGROUND: The receptors for estrogen (ESR1) and progesterone (PGR) are both part of the same signaling pathway and routinely used for breast cancer stratification. We tested the hypothesis if a coordinated analysis could add extra information for prognostic stratification. MATERIALS AND METHODS: ESR1 and PGR gene expression was first investigated by quantitative reverse transcription polymerase chain reaction in fresh-frozen invasive ductal breast cancer samples (Hamburg collective, case-control, n=317). Our results were then tested using two datasets generated by different technical approaches: i) a public DNA-chip data set (GSE3494, n=251) and ii) semiquantitative protein expression data based on immunohistochemistry (Stuttgart collective, n=18,528). RESULTS: The PGR/ESR1 gene-expression ratio was a prognostic indicator in those with ESR1/PGR-positive breast cancer (Hamburg collective), with a high PGR/ESR1 expression ratio indicating a favorable outcome. In all three collectives, the PGR/ESR1 mRNA ratio or its protein equivalent was a univariate prognostic factor and also a multivariate prognostic factor in the Hamburg and Stuttgart collectives. CONCLUSION: Calculation of the PGR/ESR1 gene-expression ratio and its immunohistochemical surrogate could be a useful and simple addition to routine breast cancer diagnostics. A high PGR/ESR1 ratio could be indicative of a favorable clinical outcome.
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Biomarcadores Tumorais/biossíntese , Neoplasias da Mama/diagnóstico , Neoplasias da Mama/genética , Receptor alfa de Estrogênio/biossíntese , Receptores de Progesterona/biossíntese , Idoso , Biomarcadores Tumorais/genética , Neoplasias da Mama/patologia , Receptor alfa de Estrogênio/genética , Estrogênios/genética , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Estimativa de Kaplan-Meier , Pessoa de Meia-Idade , Prognóstico , Receptores de Progesterona/genética , Medição de RiscoRESUMO
We present an overview of the ultramicroscopy technique we developed. Starting from developments 100 years ago, we designed a light sheet microscope and a chemical clearing to image complete mouse brains. Fluorescence of green fluorescent protein (GFP)-labeled neurons in mouse brains could be preserved with our 3DISCO clearing and high-resolution three-dimensional (3-D) recordings were obtained. Ultramicroscopy was also used to image whole mouse embryos and flies. We improved the optical sectioning of our light sheet microscope by generating longer and thinner light sheets with aspheric optics. To obtain high-resolution images, we corrected available air microscope objectives for clearing solutions with high refractive index. We discuss how eventually super resolution could be realized in light sheet microscopy by applying stimulated emission depletion technology. Also the imaging of brain function by recording of mouse brains expressing cfos-GFP is discussed. Finally, we show the first 3-D recordings of human breast cancer with light sheet microscopy as application in medical diagnostics.
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BACKGROUND: The well-characterized tubular-type of breast tumors is classified as low-risk breast cancer. PATIENTS AND METHODS: We report on the results of a retrospective analysis on clinical and biological features of 248 tubular breast tumors including follow-up and treatment data from two German series of 21,065 breast cancer cases. The majority of tumors were stage I or stage II, ER- and PR-positive and c-erbB2-negative with a 5-year survival-rate of 96.3%. 51.3% of patients received hormonal treatment, 75.5% had post-operative radiotherapy and 11.8% were treated with a chemotherapeutical regimen. CONCLUSION: Our retrospective analysis showed no treatment benefit for either anti-hormonal or chemotherapeutical regimens. Post-operative radiotherapy, however, improved the survival rate of patients with tubular carcinoma (log-rank=5, p=0.025). Our data suggest that post-operative radiotherapy is an important treatment to prolong survival for patients suffering from tubular breast cancer.
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Neoplasias da Mama/patologia , Neoplasias da Mama/terapia , Adulto , Idoso , Estudos de Coortes , Feminino , Humanos , Pessoa de Meia-Idade , Estudos RetrospectivosRESUMO
Specialized protein domains bind to posttranslational modifications (PTMs) of proteins, such as phosphorylation or glycosylation. When such PTM-binding protein domains are used as analytical tools, the functional states of cells and tissues can be determined with high precision. Here, we describe the use of recombinant CLEC10A (CD301), a human glycoreceptor of the C-type lectin family, for the detection of ligands in sections from formalin-fixed, paraffin-embedded normal and cancerous mammary tissues. A construct, in which part of the carbohydrate recognition domain (CRD) was deleted, was used as a negative control. In comparison to normal mammary glands, a pronounced staining of tumor tissues was observed. Because the construct with the truncated CRD did not show any tissue staining, the binding of the wild-type glycoreceptor can be attributed to its carbohydrate recognition domain. To distinguish our novel approach from immunohistochemistry, we propose the designation "protein domain histochemistry" (PDH).
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Neoplasias da Mama/patologia , Mama/patologia , Histocitoquímica/métodos , Lectinas Tipo C/análise , Lectinas Tipo C/metabolismo , Neoplasias da Mama/diagnóstico , Clonagem Molecular , Feminino , Células HEK293 , Humanos , Inclusão em Parafina/métodos , Polissacarídeos/metabolismo , Ligação Proteica , Estrutura Terciária de Proteína , Proteínas Recombinantes/análise , Proteínas Recombinantes/metabolismo , Fixação de Tecidos/métodosRESUMO
Chemotherapies feature a low success rate of about 25%, and therefore, the choice of the most effective cytostatic drug for the individual patient and monitoring the efficiency of an ongoing chemotherapy are important steps towards personalized therapy. Thereby, an objective method able to differentiate between treated and untreated cancer cells would be essential. In this study, we provide molecular insights into Docetaxel-induced effects in MCF-7 cells, as a model system for adenocarcinoma, by means of Raman microspectroscopy combined with powerful chemometric methods. The analysis of the Raman data is divided into two steps. In the first part, the morphology of cell organelles, e.g. the cell nucleus has been visualized by analysing the Raman spectra with k-means cluster analysis and artificial neural networks and compared to the histopathologic gold standard method hematoxylin and eosin staining. This comparison showed that Raman microscopy is capable of displaying the cell morphology; however, this is in contrast to hematoxylin and eosin staining label free and can therefore be applied potentially in vivo. Because Docetaxel is a drug acting within the cell nucleus, Raman spectra originating from the cell nucleus region were further investigated in a next step. Thereby we were able to differentiate treated from untreated MCF-7 cells and to quantify the cell-drug response by utilizing linear discriminant analysis models.
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Adenocarcinoma/patologia , Antineoplásicos/farmacologia , Neoplasias da Mama/patologia , Nucléolo Celular/efeitos dos fármacos , Análise Espectral Raman/métodos , Taxoides/farmacologia , Adenocarcinoma/tratamento farmacológico , Neoplasias da Mama/tratamento farmacológico , Linhagem Celular Tumoral , Nucléolo Celular/patologia , Docetaxel , Feminino , HumanosRESUMO
Personalized tumor chemotherapy depends on reliable assay methods, either based on molecular "predictive biomarkers" or on a direct, functional ex vivo assessment of cellular chemosensitivity. As a member of the latter category, a novel high-content platform is described monitoring human mamma carcinoma explants in real time and label-free before, during and after an ex vivo modeled chemotherapy. Tissue explants are sliced with a vibratome and laid into the microreaction chambers of a 24-well sensor test plate. Within these ~23 µl volume chambers, sensors for pH and dissolved oxygen record rates of cellular oxygen uptake and extracellular acidification. Robot-controlled fluid system and incubation are parts of the tissue culture maintenance system while an integrated microscope is used for process surveillance. Sliced surgical explants from breast cancerous tissue generate well-detectable ex vivo metabolic activity. Metabolic rates, in particular oxygen consumption rates have a tendency to decrease over time. Nonetheless, the impact of added drugs (doxorubicin, chloroacetaldehyde) is discriminable. Sensor-based platforms should be evaluated in explorative clinical studies for their suitability to support targeted systemic cancer therapy. Throughput is sufficient for testing various drugs in a range of concentrations while the information content obtained from multiparametric real-time analysis is superior to conventional endpoint assays.
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Antineoplásicos/farmacologia , Técnicas Biossensoriais/métodos , Neoplasias da Mama/tratamento farmacológico , Ensaios de Seleção de Medicamentos Antitumorais/métodos , Medicina de Precisão/métodos , Feminino , Humanos , Terapia de Alvo Molecular/métodos , Consumo de Oxigênio/fisiologia , Células Tumorais CultivadasRESUMO
Although it is increasingly recognized that the tumor biology is influenced by the tumor stroma, prognostic gene signatures are usually derived from tissue consisting of tumor cells and surrounding stroma. This study presents a compartment-specific transcriptome analysis of lung squamous cell carcinoma (SCC) samples microdissected into tumor parenchyma and stroma fractions. Typical tumor and stroma genes were identified based on the expression ratios between the two compartments. Our results indicate that in SCC many markers related to longer survival are predominantly expressed in the stroma, particularly genes of the MHC-II complex. Stromal upregulation of MHC-II genes seems crucial for a clinically relevant antitumor immune response in SCC.
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Biomarcadores Tumorais/genética , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma de Células Escamosas/genética , Perfilação da Expressão Gênica/métodos , Neoplasias Pulmonares/genética , Carcinoma Pulmonar de Células não Pequenas/diagnóstico , Carcinoma Pulmonar de Células não Pequenas/patologia , Carcinoma de Células Escamosas/diagnóstico , Carcinoma de Células Escamosas/patologia , Genes MHC da Classe II/genética , Humanos , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/patologia , Masculino , Microdissecção , Estadiamento de Neoplasias , Prognóstico , Células Estromais/metabolismo , Células Estromais/patologia , Análise de SobrevidaRESUMO
A constraint in the reliability of predictive chemosensitivity assays is linked to the fact that they analyze only a single cellular or biochemical parameter. A multiparametric test system using microsensor chips has been developed which can detect online microphysiological changes in living cells. Tumor cells were grown directly on glass- or silicon-based electronic sensor chips. Changes in extracellular pH and pO(2), reflecting metabolic activities, and changes in impedance, reflecting morphological properties, were monitored. In this study, colon and breast cancer cells as well as doxorubicin-sensitive and doxorubicin-resistant sarcoma cell lines were exposed to cytochalasin B, chloroacetaldehyde, or doxorubicin. Results show (1) reduction in medium acidification, (2) marked and rapid changes in O(2) consumption, and (3) modulations in impedance correlating with morphological changes observed in the microscope. Drug-resistant cells do not show these changes. Therefore, this microphysiological monitoring is a versatile tool for chemosensitivity testing of tumor cells.