Immunotherapy in thymic epithelial tumors: tissue predictive biomarkers for immune checkpoint inhibitors.

Thymic epithelial tumors (TETs) are rare malignant neoplasms arising in the thymus gland. Nevertheless, TETs, including thymomas (TMs), thymic carcinomas (TCs), and thymic neuroendocrine neoplasms (TNENs), are the most common mediastinal malignancies overall. A multidisciplinary approach is required for the appropriate diagnostic and therapeutic management of TETs. To date, the main therapeutic strategies are largely depended on the stage of the tumor and they include surgery with or without neoadjuvant or adjuvant therapy, represented by platinum-based chemotherapy, radiotherapy or chemoradiotherapy. Immune checkpoint inhibitors (ICIs) are ongoing under evaluation in the advanced or metastatic diseases despite the challenges related to the very low tumor mutation burden (TMB) and the high incidence of immune-related adverse events in TETs. In this regard, predictive impact of tissue biomarkers expression such as programmed cell death ligand-1 (PD-L1), and other emerging biomarkers, as well as their optimal and shared interpretation are currently under evaluation in order to predict response rates to ICIs in TETs.

Multidisciplinary Approach to the Diagnosis of Idiopathic Interstitial Pneumonias: Focus on the Pathologist's Key Role.

Idiopathic Interstitial Pneumonias (IIPs) are a heterogeneous group of the broader category of Interstitial Lung Diseases (ILDs), pathologically characterized by the distortion of lung parenchyma by interstitial inflammation and/or fibrosis. The American Thoracic Society (ATS)/European Respiratory Society (ERS) international multidisciplinary consensus classification of the IIPs was published in 2002 and then updated in 2013, with the authors emphasizing the need for a multidisciplinary approach to the diagnosis of IIPs. The histological evaluation of IIPs is challenging, and different types of IIPs are classically associated with specific histopathological patterns. However, morphological overlaps can be observed, and the same histopathological features can be seen in totally different clinical settings. Therefore, the pathologist's aim is to recognize the pathologic-morphologic pattern of disease in this clinical setting, and only after multi-disciplinary evaluation, if there is concordance between clinical and radiological findings, a definitive diagnosis of specific IIP can be established, allowing the optimal clinical-therapeutic management of the patient.

ß2-AR inhibition enhances EGFR antibody efficacy hampering the oxidative stress response machinery.

The ß2-Adrenergic receptor (ß2-ARs) is a cell membrane-spanning G protein-coupled receptors (GPCRs) physiologically involved in stress-related response. In many cancers, the ß2-ARs signaling drives the tumor development and transformation, also promoting the resistance to the treatments. In HNSCC cell lines, the ß2-AR selective inhibition synergistically amplifies the cytotoxic effect of the MEK 1/2 by affecting the p38/NF-kB oncogenic pathway and contemporary reducing the NRF-2 mediated antioxidant cell response. In this study, we aimed to validate the anti-tumor effect of ß2-AR blockade and the synergism with MEK/ERK and EGFR pathway inhibition in a pre-clinical orthotopic mouse model of HNSCC. Interestingly, we found a strong ß2-ARs expression in the tumors that were significantly reduced after prolonged treatment with ß2-Ars inhibitor (ICI) and EGFR mAb Cetuximab (CTX) in combination. The ß2-ARs down-regulation correlated in mice with a significant tumor growth delay, together with the MAPK signaling switch-off caused by the blockade of the MEK/ERK phosphorylation. We also demonstrated that the administration of ICI and CTX in combination unbalanced the cell ROS homeostasis by blocking the NRF-2 nuclear translocation with the relative down-regulation of the antioxidant enzyme expression. Our findings highlighted for the first time, in a pre-clinical in vivo model, the efficacy of the ß2-ARs inhibition in the treatment of the HNSCC, remarkably in combination with CTX, which is the standard of care for unresectable HNSCC.

Advancing the PD-L1 CPS test in metastatic TNBC: Insights from pathologists and findings from a nationwide survey.

Pembrolizumab has received approval as a first-line treatment for unresectable/metastatic triple-negative breast cancer (mTNBC) with a PD-L1 combined positive score (CPS) of ≥ 10. However, assessing CPS in mTNBC poses challenges. Firstly, it represents a novel analysis for breast pathologists. Secondly, the heterogeneity of PD-L1 expression in mTNBC further complicates the assessment. Lastly, the lack of standardized assays and staining platforms adds to the complexity. In KEYNOTE trials, PD-L1 expression was evaluated using the IHC 22C3 pharmDx kit as a companion diagnostic test. However, both the 22C3 pharmDx and VENTANA PD-L1 (SP263) assays are validated for CPS assessment. Consequently, assay-platform choice, staining conditions, and scoring methods can significantly impact the testing outcomes. This consensus paper aims to discuss the intricacies of PD-L1 CPS testing in mTNBC and provide practical recommendations for pathologists. Additionally, we present findings from a nationwide Italian survey elucidating the state-of-the-art in PD-L1 CPS testing in mTNBC.

NTRK gene aberrations in triple-negative breast cancer: detection challenges using IHC, FISH, RT-PCR, and NGS.

Triple-negative breast cancer (TNBC) is usually an aggressive disease with a poor prognosis and limited treatment options. The neurotrophic tyrosine receptor kinase (NTRK) gene fusions are cancer type-agnostic emerging biomarkers approved by the Food and Drug Administration (FDA), USA, for the selection of patients for targeted therapy. The main aim of our study was to investigate the frequency of NTRK aberrations, i.e. fusions, gene copy number gain, and amplification, in a series of TNBC using different methods. A total of 83 TNBCs were analyzed using pan-TRK immunohistochemistry (IHC), fluorescence in situ hybridization (FISH), real-time polymerase chain reaction (RT-PCR), and RNA-based next-generation sequencing (NGS). Of 83 cases, 16 showed pan-TRK positivity although no cases had NTRK-fusions. Indeed, FISH showed four cases carrying an atypical NTRK1 pattern consisting of one fusion signal and one/more single green signals, but all cases were negative for fusion by NGS and RT-PCR testing. In addition, FISH analysis showed six cases with NTRK1 amplification, one case with NTRK2 copy number gain, and five cases with NTRK3 copy number gain, all negative for pan-TRK IHC. Our data demonstrate that IHC has a high false-positive rate for the detection of fusions and molecular testing is mandatory; there is no need to perform additional molecular tests in cases negativity for NTRK by IHC. In conclusion, the NTRK genes are not involved in fusions in TNBC, but both copy number gain and amplification are frequent events, suggesting a possible predictive role for other NTRK aberrations.

A Critical Issue in Lung Cancer Cytology and Small Biopsies: DNA and RNA Extraction from Archival Stained Slides for Biomarker Detection through Real Time PCR and NGS-The Experience in Pathological Anatomy Unit.

The handling of biomaterials is crucial for precision medicine in advanced-stage lung patients with only cytology or small biopsies available. The main purpose of the study was to evaluate the quantity and quality of nucleic acids extracted from mixed stained slides (MSSs), including H&E, IHC and FISH, compared to the extraction from unstained slides (USs). A series of 35 lung adenocarcinoma surgical samples was selected to set up the method and the technical approach was validated in a series of 15 small biopsies and 38 cytological samples. DNA extracted from MSSs was adequate in all samples and the Real Time PCR was successful in 30/35 surgical samples (86%), 14/15 small biopsies (93%), and 33/38 cytological samples (87%). NGS using DNA extracted from MSSs was successful in 18/35 surgical samples (51%), 11/15 small biopsies (73%), and 26/38 cytological samples (68%). RNA extracted from MSSs was unsatisfactory in all cases showing an inadequate degree of fragmentation. Our technical approach based on the recovery of stained slides could represent a strategic way forward for DNA-based biomarker testing in lung cancer cases without biomaterials. The RNA extracted from MSSs did not represent a successful approach.

Implementation of BRCA mutations testing in formalin-fixed paraffin-embedded (FFPE) samples of different cancer types.

BRCA1 and BRCA2 are onco-suppressor genes involved in the DNA repair mechanism. The presence of BRCA1/2 mutations confers a higher risk of developing several cancer types. To date, the FDA approved various PARP inhibitors to treat selected BRCA1/2 mutated oncologic patients. At first, PARP inhibitors were approved for patients with ovarian and breast cancers, and subsequently for metastatic pancreatic adenocarcinoma and metastatic castration-resistant prostate cancer after the treatment with chemotherapy. The current guidelines for BRCA testing are very heterogeneous between the different types of tumors regarding the diagnostic algorithm and the type of sample to analyze, such as the blood for the germline mutations and the tumoral tissue for the somatic mutations. Few data have currently been described regarding the detection of BRCA1/2 somatic mutations in formalin-fixed paraffin-embedded (FFPE) samples. In this review, we propose an overview of the BRCA mutations in FFPE samples of several cancers, including breast, ovarian, fallopian tube, primary peritoneal, prostate, and pancreatic cancer. We summarize the types and the frequency of BRCA mutations, the guidelines approved for the test, the molecular assays used for the detection and the PARP inhibitors approved for each tumor type.

The prognostic value of histopathology in invasive lung adenocarcinoma: a comparative review of the main proposed grading systems.

INTRODUCTION: An accurate histological evaluation of invasive lung adenocarcinoma is essential for a correct clinical and pathological definition of the tumour. Different grading systems have been proposed to predict the prognosis of invasive lung adenocarcinoma. AREAS COVERED: Invasive non mucinous lung adenocarcinoma is often morphologically heterogeneous, consisting of complex combinations of architectural patterns with different proportions. Several grading systems for non-mucinous lung adenocarcinoma have been proposed, being the main based on architectural differentiation and the predominant growth pattern. Herein we perform a thorough review of the literature using PubMed, Scopus and Web of Science and we highlight the peculiarities and the differences between the main grading systems and compare the data about their prognostic value. In addition, we carried out an evaluation of the proposed grading systems for less common histological variants of lung adenocarcinoma, such as fetal adenocarcinoma and invasive mucinous adenocarcinoma. EXPERT OPINION: The current IASLC grading system, based on the combined score of predominant growth pattern plus high-grade histological pattern, shows the stronger prognostic significance than the previous grading systems in invasive non mucinous lung adenocarcinoma.

Pulmonary leiomyosarcoma arising in pulmonary hamartoma: an exceptional occurrence in a rare tumor.

A solitary peripheral lung nodule was found in the left lung of a 52-year-old man. It was located in the lower lobe and measured 18.5 cm of major axis on chest computed tomography. A tru-cut core biopsy was obtained and a proliferation of bland, monomorphic, spindle cells in interlacing fascicles was observed. Accordingly, a surgical resection of the neoplasm was subsequently carried out. Macroscopically, the tumor appeared as a well-circumscribed nodule with a firm and whitish cut surface. Histologically, the neoplasm was predominantly composed of bland and monomorphic spindle cells, with a predominantly fascicular growth pattern, in which many tubular and cleft-like spaces of entrapped normal respiratory epithelium were involved. Myxoid change, stromal hyalinization and scattered bizarre mononucleated and multinucleated cells were also observed. Based on clinico-morphological, immunophenotypical and molecular features, we made a diagnosis of malignant transformation of pulmonary adenoleiomyomatous hamartoma into pulmonary leiomyosarcoma. As far as we know, this is the first described case of this exceptionally rare occurrence in an already rare neoplasm.

AXL and MET Tyrosine Kinase Receptors Co-Expression as a Potential Therapeutic Target in Malignant Pleural Mesothelioma.

Malignant pleural mesothelioma (MPM) is a highly lethal malignancy that unfortunately cannot benefit from molecularly targeted therapies. Although previous results showed the pivotal role of various receptor tyrosine kinases (RTKs) in MPM tumorigenesis, the treatment with a single inhibitor targeting one specific RTK has been shown to be ineffective in MPM patients. The main aim of the present study was to investigate the potential role of AXL and MET receptors in MPM and the possible efficacy of treatment with AXL and MET multitarget inhibitors. Immunohistochemical and FISH analyses were performed in a wide series of formalin-fixed paraffin-embedded MPM samples to detect the expression of two receptors and the potential gene amplification. In vitro studies were performed to evaluate putative correlations between the target's expression and the cell sensitivity to AXL-MET multitarget inhibitors. In our series, 10.4% of cases showed a co-expression of AXL and MET, regardless of their ligand expression, and the gene amplification. Furthermore, our in vitro results suggest that the concomitant pharmacological inhibition of AXL and MET may affect the proliferative and aggressiveness of MPM cells. In conclusion, the subset of MPM patients with AXL-MET co-activation could benefit from treatment with specific multitarget inhibitors.

Microsatellite Instability: From the Implementation of the Detection to a Prognostic and Predictive Role in Cancers.

Microsatellite instability (MSI) has been identified in several tumors arising from either germline or somatic aberration. The presence of MSI in cancer predicts the sensitivity to immune checkpoint inhibitors (ICIs), particularly PD1/PD-L1 inhibitors. To date, the predictive role of MSI is currently used in the selection of colorectal cancer patients for immunotherapy; moreover, the expansion of clinical trials into other cancer types may elucidate the predictive value of MSI for non-colorectal tumors. In clinical practice, several assays are used for MSI testing, including immunohistochemistry (IHC), polymerase chain reaction (PCR) and next-generation sequencing (NGS). In this review, we provide an overview of MSI in various cancer types, highlighting its potential predictive/prognostic role and the clinical trials performed. Finally, we focus on the comparison data between the different assays used to detect MSI in clinical practice.

An Integrated In Silico, In Vitro and Tumor Tissues Study Identified Selenoprotein S (SELENOS) and Valosin-Containing Protein (VCP/p97) as Novel Potential Associated Prognostic Biomarkers in Triple Negative Breast Cancer.

BACKGROUND: Triple negative breast cancer (TNBC) is a heterogeneous group of tumors with early relapse, poor overall survival, and lack of effective treatments. Hence, new prognostic biomarkers and therapeutic targets are needed. METHODS: The expression profile of all twenty-five human selenoproteins was analyzed in TNBC by a systematic approach.In silicoanalysis was performed on publicly available mRNA expression datasets (Cancer Cell Line Encyclopedia, CCLE and Library of Integrated Network-based Cellular Signatures, LINCS). Reverse transcription quantitative PCR analysis evaluated selenoprotein mRNA expression in TNBC versus non-TNBC and normal breast cells, and in TNBC tissues versus normal counterparts. Immunohistochemistry was employed to study selenoproteins in TNBC tissues. STRING and Cytoscape tools were used for functional and network analysis. RESULTS: GPX1, GPX4, SELENOS, TXNRD1 and TXNRD3 were specifically overexpressed in TNBC cells, tissues and CCLE/LINCS datasets. Network analysis demonstrated that SELENOS-binding valosin-containing protein (VCP/p97) played a critical hub role in the TNBCselenoproteins sub-network, being directly associated with SELENOS expression. The combined overexpression of SELENOS and VCP/p97 correlated with advanced stages and poor prognosis in TNBC tissues and the TCGA dataset. CONCLUSION: Combined evaluation of SELENOS and VCP/p97 might represent a novel potential prognostic signature and a therapeutic target to be exploited in TNBC.

Synchronous intrathyroidal parathyroid carcinoma and thyroid carcinoma: case report and review of the literature.

BACKGROUND: Parathyroid carcinoma is a rare endocrine malignancy, rarer when synchronous with a non medullary well differentiated thyroid carcinoma. Parathyroid carcinoma accounts of 0.005% of all malignant tumors and it is responsible for less than 1% of primary hyperparathyroidism. The intrathyroidal localization of a parathyroid gland is not frequent with a reported prevalence of 0.2%. Carcinoma of parathyroids with intrathyroidal localization represents an even rarer finding, reported in only 16 cases described in literature. The rare constellation of synchronous parathyroid and thyroid carcinomas has prompted us to report our experience and perform literature review. CASE PRESENTATION: We herein report a case of a 63-years-old man with multinodular goiter and biochemical diagnosis of hyperparathyroidism. Total thyroidectomy with radio-guide technique using gamma probe after intraoperative sesta-MIBI administration and intraoperative PTH level was performed. The high radiation levels in the posterior thyroid lobe discovered an intrathyroidal parathyroid. Microscopic examination revealed a parathyroid main cell carcinoma at the posterior thyroidal left basal lobe, a classic papillary carcinoma at the same lobe and follicular variant of papillary carcinoma at the thyroidal right lobe. To the best of our knowledge, this is the first case documenting a synchronous multicentric non medullary thyroid carcinomas and intrathyroidal parathyroid carcinoma. CONCLUSIONS: Our experience was reported and literature review underlining challenging difficulties in diagnostic workup and surgical management was carried out.

A Trimodality, Four-Step Treatment including Chemotherapy, Pleurectomy/Decortication and Radiotherapy in Early-Stage Malignant Pleural Mesothelioma: A Single-Institution Retrospective Case Series Study.

BACKGROUND: Multimodality treatment is considered the best treatment strategy for malignant pleural mesothelioma (MPM). However, the ideal combination of them is still a matter of controversy. Here, we report a case series of MPM treated with a trimodality approach: induction chemotherapy (CT), pleurectomy/decortication (P/D), postoperative radiotherapy (RT) and post-operative CT. METHODS: A retrospective case series of 17 MPM patients treated between 2013 and 2020 is presented. Patients had epithelial or mixed MPM diagnosed by video-assisted thoracoscopy and pathologic IMIG stage I or II disease. Treatment details and radiological data were collected. Induction therapy consisted of combination of cisplatin and pemetrexed, every 21 days for two cycles. P/D was performed 4-6 weeks after induction CT, post-operative RT 3-6 weeks after surgery, while post-operative CT was given 4-6 weeks after RT, with the same schedule of induction. RESULTS: All patients showed objective response or stability of disease at the restaging following induction CT and underwent surgery by posterolateral thoracotomy. There were two cases of cardiac arrest as major intraoperative complication, both resolved by manual cardiac massage. Minor complications included one hemidiaphragm elevation, 1 anemia requiring blood transfusion, one wound infection, and two persistent air leaks. Median overall survival was 32.1 months, median progression free survival was 23.7 months. CONCLUSIONS: These results suggest the feasibility of these trimodality treatment scheme for early stage MPM patients. Larger series and long-term prospective studies are needed to confirm the validity of this strategy.

Nuck cyst: a rare cause of inguinal swelling in infancy.

BACKGROUND: Inguinal and/or inguino-scrotal swellings, such as hernia and hydrocele, are among the commonest anomalies in childhood. Hydrocele of the canal of Nuck is an uncommon diagnosis and a rare cause of swelling in women that occurs due to a patent vaginal process. METHODS: From January 2001 to January 2016, 353 female patients 1-14 years of age were admitted to our university hospital division for inguinal swelling. We have performed 403 inguinal approaches, and of these, 399 (99%) had inguinal hernias, 3 (0.74%) had a cyst of the canal of Nuck, and 1 (0.24%) had a lipoma. All of the patients with Nuck cysts underwent surgical exploration of the swelling through a right inguinal skin crease incision. RESULTS: The patients were between the ages of 1 and 8 years. The cyst sizes varied between 25 and 40 mm. All the patients exhibited right, tender, painless, non-reducible masses. In all patients, ultrasound confirmed the suspected diagnosis. The histological findings revealed fibrous-walled cystic formations with mild chronic inflammatory infiltrate that were covered by mesothelial epithelium. The patients' postoperative follow-ups at 1, 6 and 12 months revealed normally healed incisions with no recurrences. CONCLUSIONS: The surgical findings and the histological demonstrations of serous epithelium seemed to validate the hypothesis that the patency of the inguinal canal combined with fluid secretion of the peritoneal serosa participated in the formation of the cysts. Surgery with high ligature of the vaginal process is considered the therapy of choice for this pathology.

Current and potential immunohistochemical biomarkers for prognosis and therapeutic stratification of breast carcinoma.

The identification of biomarkers on cancer tissue samples could be obtained through several technologies. In this setting, the immunohistochemistry and in situ hybridization are accessible in most pathology laboratories. Particularly, immunohistochemistry can be used not only for diagnostic issues, but also to define prognostic classes and to define response to specific therapies. Particularly the last applications have been firstly developed in the breast cancer pathology. In addition, the development of molecular classification proposed some prognostic/predictive classes that could be easily defined by immunohistochemistry. Thus, the role of the pathologists has become increasingly important in the definition of prognosis and in the choice therapy, because the immunohistochemical biomarkers are used to guide treatment, to classify breast cancer into biologically and prognostically distinct subtypes. In this review, we will provide information on the current application of the immunohistochemical biomarkers useful in the management of breast cancer patients. Moreover, we consider the application of immunohistochemistry in the definition of the most promising biomarkers derived from molecular studies of the breast cancer, that in the future could integrate the characterization of breast cancer into clinical practice.

Double-staining Immunohistochemistry Reveals in Malignant Pleural Mesothelioma the Coexpression of ERCC1 and RRM1 as a Frequent Biological Event Related to Poorer Survival.

Malignant pleural mesothelioma (MPM) is a rare cancer with a poor prognosis. To date, standard MPM therapy is still limited to surgery, radiotherapy, and chemotherapy, including pemetrexed and platinum compounds. The main mechanisms of platinum resistance are associated with DNA repair pathways. Excision repair cross-complementing group 1 (ERCC1) and ribonucleotide reductase subunit M1 (RRM1) are important components of the DNA repair, considered as prognostic and predictive biomarkers in various cancer types. The main goal of the present study was to investigate the ERCC1 and RRM1 expression and their potential impact on outcome in this tumor. A series of 73 MPM, mainly treated with a platin-based regimen, was collected and the immunohistochemistry tests were performed to assess ERCC1 and RRM1 expression. In addition, a multiplex immunohistochemistry has been validated to detect simultaneously the 2 proteins on the same slide. In our series, 36 of 73 cases showed ERCC1 expression and 55 of 73 showed RRM1 expression. The double immunohistochemical staining showed the coexpression of ERCC1/RRM1 in 34 of 73 cases. A significant association between ERCC1 and RRM1 expression was observed in our series (P<0.05). Patients with ERCC1/RRM1 coexpression experienced shorter median overall survival (6.6 vs. 13.8 mo, log-rank=7688; P=0.006). Our results suggest that the coexpression of ERCC1/RRM1 could define a group of MPM patients with the worst prognosis who should need likely alternative treatment. In conclusion, we propose the putative usefulness of ERCC1/RRM1 coexpression as prognostic biomarkers for overall survival in MPM.

Endoscopic resection of tracheal lobular capillary haemangioma with ultrasonically activated device.

We reported the case of a 55-year-old man with a large tracheal lobular capillary haemangioma attached to posterior tracheal wall and successfully managed with arterial embolization followed by endoscopic resection using Harmonic™ ACE Plus. Because of the high risk of bleeding, Harmonic™ was used in this case due to its ability to cut and cauterize simultaneously. The instrument jaw repeatedly grasped the attachment point of tumor, and then the cavitation effect, created by the longitudinal vibration of the blade tip, separated it from the posterior tracheal wall, reducing the risk of perforation. Yet, the ultrasonic energy denatured proteins and coagulated the vessels, preventing the bleeding during resection. No complications occurred during and after the procedure. Twelve-month follow-up showed no recurrence.

Heterogeneity of PD-L1 Expression in Lung Mixed Adenocarcinomas and Adenosquamous Carcinomas.

Immune checkpoint inhibitors against programmed cell death protein 1/programmed death-ligand 1 (PD-L1) have proven to be remarkably effective in non-small cell lung cancer. PD-L1 represents a predictive biomarker in lung cancer, although its heterogenous expression represents an emerging challenge for accurate biomarker-based patient selection. Lung adenocarcinomas (ADCs) show a high rate of intratumor morphologic heterogeneity that may reflect a heterogenous molecular and immunophenotypic profile. The aim of our study was to analyze the expression of PD-L1 in different intratumor subtypes and/or growth patterns in a series of mixed adenocarcinomas (mADCs) and adenosquamous lung carcinomas (AdSqLCs). As many as 73 mADCs and 6 AdSqLCs were selected. Comprehensive histologic subtyping was performed, and PD-L1 expression was assessed by immunohistochemistry assay using different primary antibodies and automated immunostainers. Overall, PD-L1 expression was observed in 37 of 79 cases (39.2%) (31 mADCs and all AdSqLCs). PD-L1 expression was heterogenous in 22 of 37 PD-L1-positive cases (23.2% mADC and 83% AdSqLC). PD-L1 expression was observed more frequently in ADC with solid pattern. Heterogeneity of PD-L1 expression was significantly related to the presence of micropapillary (P=0.028) and solid (P=0.017) patterns. All PD-L1-positive cases were epidermal growth factor receptor wild-type, 2 cases harbored concomitantly PD-L1 expression and ALK rearrangement. Our data suggest that PD-L1 expression is quite heterogenous in mADCs and AdSqLCs, partly contributing to explaining the discrepant results between biopsy and surgical resections and discordant clinical effectiveness in regard to PD-L1-positive or negative ADC diagnosed on cytology/small biopsy.

Structural analysis of human SEPHS2 protein, a selenocysteine machinery component, over-expressed in triple negative breast cancer.

Selenophosphate synthetase 2 (SEPHS2) synthesizes selenide and ATP into selenophosphate, the selenium donor for selenocysteine (Sec), which is cotranslationally incorporated into selenoproteins. The action and regulatory mechanisms of SEPHS2 as well as its role in carcinogenesis (especially breast cancer) remain ambiguous and need further clarification. Therefore, lacking an experimentally determined structure for SEPHS2, we first analyzed the physicochemical properties of its sequence, modeled its three-dimensional structure and studied its conformational behavior to identify the key residues (named HUB nodes) responsible for protein stability and to clarify the molecular mechanisms by which it induced its function. Bioinformatics analysis evidenced higher amplification frequencies of SEPHS2 in breast cancer than in other cancer types. Therefore, because triple negative breast cancer (TNBC) is biologically the most aggressive breast cancer subtype and its treatment represents a challenge due to the absence of well-defined molecular targets, we evaluated SEPHS2 expression in two TNBC cell lines and patient samples. We demonstrated mRNA and protein overexpression to be correlated with aggressiveness and malignant tumor grade, suggesting that this protein could potentially be considered a prognostic marker and/or therapeutic target for TNBC.