Early-Stage Non-Small Cell Lung Cancer: Prevalence of Actionable Alterations in a Monocentric Consecutive Cohort

Early-stage (ES) non-small cell lung cancer (NSCLC) is diagnosed in about 30% of cases. The preferred treatment is surgery, but a significant proportion of patients experience recurrence. Neoadjuvant and adjuvant chemotherapy has a limited clinical benefit. EGFR tyrosine kinase inhibitors and immunotherapy have recently opened new therapeutic scenarios. However, only a few data are available about the ES-NSCLC molecular landscape and the impact of oncogene addiction on therapy definition. Here, we determined the prevalence of the main lung cancer driver alterations in a monocentric consecutive cohort. Molecular analysis was performed on 1122 cases, including 368 ES and 754 advanced NSCLC. The prevalence of actionable alterations was similar between early and advanced stages. ES-NSCLC was significantly enriched for MET exon-14 skipping alterations and presented a lower prevalence of BRAF p.(V600E) mutation. PD-L1 expression levels, evaluated according to actionable alterations, were higher in advanced than early tumors harboring EGFR, KRAS, MET alterations and gene fusions. Taken together, these results confirm the value of biomarker testing in ES-NSCLC. Although approved targeted therapies for ES-NSCLC are still limited, the identification of actionable alterations could improve patients' selection for immunotherapy, favoring the enrollment in clinical trials and allowing a faster treatment start at disease recurrence.

Endobronchial ultrasound-transbronchial needle aspiration: effectiveness and accuracy in non-small cell lung cancer staging

INTRODUCTION

Endobronchial ultrasound-transbronchial needle aspiration (EBUS-TBNA) has a cardinal role in the diagnosis and staging of non-small cell lung cancer (NSCLC), providing an accurate nodal staging in a less invasive way than surgical biopsy. The aim of this study was to assess the diagnostic accuracy of EBUS-TBNA in the pre-operative NSCLC mediastinal staging, as well as to evaluate EBUS-TBNA specificity and sensibility in our cohort.

METHODS

We retrospectively analyzed data of NSCLC patients who underwent EBUS-TBNA followed by major pulmonary resection between January 2020 and December 2022. EBUS-TBNA was performed in patients with NSCLC (central T ≤ 3 cm, peripheral/central T > 3 cm), following the ESTS guidelines. The target nodes were selected on the basis of their radiologic/metabolic characteristics. Each procedure was conducted together with rapid on-site cytological evaluation (ROSE).

RESULTS

Twenty-five patients were included (M/F = 17/8). At least three needle passages on each target lymph node were performed. No complications during or after the procedures occurred. We found a 100% correspondence between ROSE on the sampled nodes and postoperative pathologic findings. An upstaging occurred in three cases (12%) because of the involvement of stations 5 and 6 (not accessible via EBUS), while the only case of downstaging (N2 → N0, 4%) was probably due to intercurrent neoadjuvant chemotherapy. In all cases, EBUS-TBNA has proved to achieve a diagnostic procedure on the target nodes.

CONCLUSIONS

EBUS-TBNA is a safe and effective procedure that offers high sensitivity and specificity when performed together with ROSE, which improves the accuracy of sampling. Doubt on nodal stations 5 and 6 involvement should be settled by other techniques.

A Misleading Case of NTRK-Rearranged Papillary Thyroid Carcinoma

Herein, we present a misleading case of advanced papillary thyroid carcinoma with lung, node, and pleural metastases, initially diagnosed as metastatic lung adenocarcinoma with papillary features, based on the histological and immunohistochemical analysis of a pleural biopsy. Between August 2019 and August 2020, the patient received 2 ineffective lines of systemic therapy, including a first line of chemotherapy with cisplatin and pemetrexed, and a second line of immunotherapy with atezolizumab. Comprehensive genomic profiling by next-generation sequencing on the archival pleural biopsy revealed an NTRK1-TMP3 fusion and comutation of the TERT promoter, commonly found in papillary thyroid carcinoma. After palliative partial thyroidectomy that confirmed the diagnosis of papillary thyroid carcinoma, in February 2021, the patient was enrolled in the STARTRK-2 GO40782 basket trial and received entrectinib, an oral pan-TRK inhibitor specifically targeting NTRK-rearranged tumors. After initially experiencing drug-related grade 2 anorexia, dysgeusia, and neurotoxicity and grade 3 asthenia, the dose was reduced, and an excellent and durable objective response was observed.

Melanocortin receptor 4 as a new target in melanoma therapy: Anticancer activity of the inhibitor ML00253764 alone and in association with B-raf inhibitor vemurafenib

The aim of our study is to investigate in vitro and in vivo MC4R as a novel target in melanoma using the selective antagonist ML00253764 (ML) alone and in combination with vemurafenib, a B-rafV600E inhibitor. The human melanoma B-raf mutated A-2058 and WM 266-4 cell lines were used. An MC4R null A-2058 cell line was generated using a CRISPR/Cas9 system. MC4R protein expression was analysed by western blotting, immunohistochemistry, and immunofluorescence. Proliferation and apoptotic assays were performed with ML00253764, whereas the synergism with vemurafenib was evaluated by the combination index (CI) and Loewe methods. ERK1/2 phosphorylation and BCL-XL expression were quantified by western blot. In vivo experiments were performed in Athymic Nude-Foxn1nu male mice, injecting subcutaneously melanoma cells, and treating animals with ML, vemurafenib and their concomitant combination. Comet and cytome assays were performed. Our results show that human melanoma cell lines A-2058 and WM 266-4, and melanoma human tissue, express functional MC4R receptors on their surface. MC4R receptors on melanoma cells can be inhibited by the selective antagonist ML, causing antiproliferative and proapoptotic activity through the inhibition of phosphorylation of ERK1/2 and a reduction of BCL-XL. The concomitant combination of vemurafenib and ML caused a synergistic effect on melanoma cells in vitro and inhibited in vivo tumor growth in a preclinical model, without causing mouse weight loss or genotoxicity. Our original research contributes to the landscape of pharmacological treatments for melanoma, providing MC4R antagonists as drugs that can be added to established therapies.

SARS-CoV-2 spread to endocrine organs is associated with obesity: an autopsy study of COVID-19 cases

PURPOSE

SARS-CoV-2 infection may be limited to the respiratory tract or may spread to multiple organs. Besides disease severity, factors associated with virus spread within the host are elusive. Here, we tried to identify features associated with SARS-CoV-2 spread to endocrine organs.

METHODS

In a retrospective autoptic cohort of 51 subjects who died because of COVID-19, we analyzed the severity and type of lung pathology, patients' features and the detection of virus in thyroid, testis, adrenal gland, pancreas, anterior pituitary, and the white adipose tissue (WAT).

RESULTS

The SARS-CoV-2 genome was detected in endocrine organs of 30/51 cases. The anterior pituitary and WAT were most frequently positive for virus. While pathological features of lung were not associated with the presence of virus in endocrine organs, obesity (BMI > 30) was significantly associated to virus detection in pancreas (p = 0.01) and thyroid (p = 0.04). WAT infection was detected more frequently in males (p = 0.03).

CONCLUSION

In subject with obesity dying of COVID-19, the virus frequently spreads to endocrine organs. The findings emphasize the need for optimal treatment of patients with obesity at the very onset of COVID-19. Since post-COVID conditions remain a major issue worldwide, a rigorous follow-up of endocrine function-especially of thyroid and pancreas-is advocated in subjects with obesity.

Robotic versus Open Surgery in Locally Advanced Non-Small Cell Lung Cancer: Evaluation of Surgical and Oncological Outcomes

Locally advanced non-small cell lung cancer (NSCLC) consists of a heterogeneous group, with different pulmonary extension and lymph nodal involvement. Robotic surgery can play a key role in these tumours thanks to its technological features, although open surgery is still considered the gold-standard approach. Our study aims to evaluate the surgical and oncological outcomes of locally advanced NSCLC patients who underwent robotic surgery in a high-volume centre. Data from consecutive patients with locally advanced NSCLC who underwent robotic lobectomy were retrospectively analysed and compared with patients treated with open surgery. Clinical characteristics and surgical and oncological information were evaluated. From 2010 to 2020, 131 patients underwent anatomical lung resection for locally advanced NSCLC. A total of 61 patients were treated with robotic surgery (46.6%); the median hospitalization time was 5.9 days (range 2-27) and the postoperative complication rate was 18%. Open surgery was performed in 70 patients (53.4%); the median length of stay was 9 days (range 4-48) and the postoperative complication rate was 22.9%. The median follow-up time was 70 months. The 5-year overall survival was 34% in the robotic group and 31% in the thoracotomy group. Robotic surgery can be considered safe and feasible not only for early stages but also for the treatment of locally advanced NSCLC.

New Immunohistochemical Markers for Pleural Mesothelioma Subtyping

Pleural mesothelioma (PM) comprises three main subtypes: epithelioid, biphasic and sarcomatoid, which have different impacts on prognosis and treatment definition. However, PM subtyping can be complex given the inter- and intra-tumour morphological heterogeneity. We aim to use immunohistochemistry (IHC) to evaluate five markers (Mesothelin, Claudin-15, Complement Factor B, Plasminogen Activator Inhibitor 1 and p21-activated Kinase 4), whose encoding genes have been previously reported as deregulated among PM subtypes. Immunohistochemical expressions were determined in a case series of 73 PMs, and cut-offs for the epithelioid and non-epithelioid subtypes were selected. Further validation was performed on an independent cohort (30 PMs). For biphasic PM, the percentage of the epithelioid component was assessed, and IHC evaluation was also performed on the individual components separately. Mesothelin and Claudin-15 showed good sensitivity (79% and 84%) and specificity (84% and 73%) for the epithelioid subtype. CFB and PAK4 had inferior performance, with higher sensitivity (89% and 84%) but lower specificity (64% and 36%). In the biphasic group, all markers showed different expression when comparing epithelioid with sarcomatoid areas. Mesothelin, Claudin-15 and CFB can be useful in subtype discrimination. PAI1 and PAK4 can improve component distinction in biphasic PM.

SMARCA4 as a support for the differential diagnosis of poorly differentiated lung carcinomas

Among non-small cell lung cancers (NSCLCs), sarcomatoid carcinomas account for 3%. They are rare tumours with a poor prognosis, classified into three subgroups, namely pleomorphic carcinoma, pulmonary blastoma and carcinosarcoma. In the 5th edition of WHO Classification of Thoracic Tumours more space is given to SMARC4-deficient lung cancers. Although studies on SMARCA4-deficient lung tumours are limited, a small percentage of SMARCA4 loss is present within NSCLCs. This finding is clinically relevant, as the loss of the SMARCA4 gene is associated with a worse prognosis. In our study, we analysed the presence of the main catalytic subunit of the SMARCA4 gene, the BRG1 protein, in 60 sarcomatoid lung tumours. The results of our study show that 5.3% of sarcomatoid carcinomas have BRG1-loss in tumour cells, proving that a non-negligible amount of lung sarcomatoid carcinomas are SMARCA4-deficient. These data open the debate on the necessity of including the detection of SMARCA4 within a standardised immunohistochemical panel.

Different pathological response and histological features following neoadjuvant chemotherapy or chemo-immunotherapy in resected non-small cell lung cancer

Introduction

Non-small cell lung cancer (NSCLC) is the leading cause of cancer incidence and mortality worldwide. Neoadjuvant chemo-immunotherapy has led to clinical benefits in resectable NSCLC in comparison to chemo-therapy alone. Major pathological response (MPR) and pathological complete response (pCR) have been used as surrogates of neoadjuvant therapy response and clinical outcomes. However, the factors affecting the pathological response are still controversial. Therefore, in this study we retrospectively examined MPR and pCR in two different cohorts of NSCLC patients, 14 treated by chemotherapy and 12 by chemo-immunotherapy in the neoadjuvant setting.

Methods

In resected tumor specimens, different histological characteristics were evaluated: necrosis, fibrosis, inflammation, presence of organizing pneumonia, granuloma, cholesterol cleft, and reactive epithelial alterations. In addition, we evaluated how MPR impacts on event-free survival (EFS) and overall survival (OS). In a small group of patients treated by chemo-immunotherapy, a gene expression analysis of the Hippo pathway was performed both in preoperative biopsies and matched post-surgical specimens.

Results

We observed a better pathological response in the chemo-immunotherapy treated cohort: 6/12 patients (50.0%) achieved a MPR ≤10% and 1/12 (8.3%) achieved pCR both on primary tumor and on lymph nodes. On the contrary, no patient treated with chemotherapy alone achieved pCR or MPR ≤10%. A higher amount of stroma in the neoplastic bed was observed in patients treated with immuno-chemotherapy. Moreover, patients achieving better MPR (including pCR) had significantly improved overall survival (OS) and event-free survival (EFS). After neoadjuvant chemo-immunotherapy, residual tumors showed a remarkable upregulation of genes consistent with the activation of YAP/TAZ. Also, alternative checkpoint, such as CTLA-4, were enhanced.

Discussion

Our findings showed that neoadjuvant chemo-immunotherapy treatment improves MPR and pCR thus resulting in better EFS and OS. Moreover, a combined treatment could induce different morphological and molecular changes in comparison to chemotherapy alone, thus giving new insights in the assessment of pathological response.

An asymptomatic giant AB thymoma in a patient with Down syndrome: a case report

Background

Mediastinal mass management may represent a real challenge for all the physicians who deal with it. Mediastinum, in fact, contains different vital structures which are often involved by growing neoplasms with increasing severity. Therefore, up to 60% of the patients with mediastinal mass are symptomatic, according to the structure involved. Different neoplasms may arise essentially from all mediastinal organs, whereas thymic epithelial tumors and lymphomas represent more than 90% of mediastinal tumors.

Case Description

We report the first case described of a giant asymptomatic mediastinal mass in a 43-year-old male affected by Down syndrome (DS), turned out to be a thymoma, treated exclusively and successfully with radical surgery. Despite the absence of any symptoms, the giant thymoma infiltrated the diaphragm, the pericardium, the upper lobe of the left lung together with the left phrenic nerve resulting in the compression of heart and great vessels.

Conclusions

To date, this is the first description of a thymic malignancy in a patient with DS, that usually is characterized by a low-incidence of solid tumor except for germ-cells ones. Surgery has been extremely challenging, due the clinical condition of the patient together with the tumor features; nevertheless, oncological radicality criteria were completely fulfilled. After four years from surgery, the patient is alive and still disease-free, highlighting the importance of radical surgery.

COVID-19 pandemic impact on cytopathology practice in the post-lockdown period: An international, multicenter study

BACKGROUND

In a previous worldwide survey, the authors showed a drastic reduction in the number of cytological specimens processed during the coronavirus disease 2019 "lockdown" period along with an increase in malignancy rates. To assess the continued impact of the pandemic on cytological practices around the world, they undertook a second follow-up worldwide survey collecting data from the post-lockdown period (2020).

METHODS

Participants were asked to provide data regarding their cytopathology activity during the first 12 weeks of their respective national post-lockdown period (2020), which ranged from April 4 to October 31. Differences between the post-lockdown period and the corresponding 2019 period were evaluated, and the authors specifically focused on rates of malignant diagnoses.

RESULTS

A total of 29 respondents from 17 countries worldwide joined the survey. Overall, a lower number of cytological specimens (n = 236,352) were processed in comparison with the same period in 2019 (n = 321,466) for a relative reduction of 26.5%. The overall malignancy rate showed a statistically significant increase (12,442 [5.26%] vs 12,882 [4.01%]; P < .001) during the same time period. Similar results were obtained if both malignancy and suspicious for malignancy rates were considered together (15,759 [6.58%] vs 16,011 [4.98%]; P < .001).

CONCLUSIONS

The data showed a persistent reduction in the cytological specimen volume during the post-lockdown period (2020). However, the relative increase in the cytological workload in the late part of the post-lockdown is a promising finding of a slow return to normality.

Bilateral testicular metastases of medullary thyroid carcinoma in an adult male with multiple endocrine neoplasia 2A syndrome: case report and review of literature

INTRODUCTION

Medullary thyroid cancer (MTC) is a rare endocrine tumor, which can be sporadic or familial, as a component of multiple endocrine neoplasia 2 (MEN2). Overall, 10% of MTC cases have already developed at presentation or will develop metastasis during follow-up. Testicular metastases are exceptional and only one case of unilateral testis involvement by metastatic MTC has been already reported in literature. We described the first known case of asymptomatic bilateral testicular MTC metastases, discovered incidentally at testicular ultrasound (US) performed for unrelated reasons.

CASE PRESENTATION

A Latin American 32-year-old man with MEN 2A syndrome and metastatic MTC underwent andrological and urological examination due to premature ejaculation. US imaging showed two symmetrical hypoechoic lesions involving both testes. Suspecting a bilateral testicular cancer, the patient underwent excision biopsy of both testicular lesions. Histopathology and immunohistochemical examinations documented metastatic MTC of both testicular lesions.

CONCLUSION

Beyond its rarity, testis should be considered as a potential metastatic site of MTC, especially in patients with advanced disease.

ESTABLISHED FACTS

Distant metastases are present at the diagnosis in 10-15% of patients with medullary thyroid carcinoma (MTC). Testicular metastases are anecdotal. Only one case of unilateral testis involvement by metastatic MTC has been reported in the literature.

NOVEL INSIGHTS

Testis should be considered as a possible site of metastases in patients with diffuse metastatic MTC. Testicular ultrasound could be considered as an useful tool for the evaluation and follow-up of metastatic MTC.

Activation of Type I and Type II Interferon Signaling in SARS-CoV-2-Positive Thyroid Tissue of Patients Dying from COVID-19

Background: Thyroid dysfunctions have been reported after Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection. However, the biological mechanisms behind these conditions remain unexplored. Herein, we report on changes of the immune transcriptome in autoptic thyroid tissues of people who have died from coronavirus disease 2019 (COVID-19). Methods: Twenty-five autoptic thyroid specimens of subjects dying from COVID-19 were investigated. Eleven autoptic thyroid specimens of subjects dying from causes other than infectious conditions served as controls. RNA transcripts of 770 immune-related genes together with RNA genomes of multiple coronavirus types were measured by the nCounter system. Reverse transcription-polymerase chain reaction for two SARS-CoV-2 genes was used to assess virus positivity. Results were validated by immunohistochemistry. Results: The SARS-CoV-2 genome and antigens were detected in 9 of 25 (36%) thyroid specimens from the COVID-19 cohort. Virus-negative thyroid tissues from COVID-19 subject did not show changes of gene transcription nor significant numbers of infiltrating immune cells. Conversely, SARS-CoV-2-positive thyroid specimens showed marked upregulation of immune genes, especially those proper of the type I and type II interferon (IFN) pathways. In infected tissues, infiltrates of innate immune cells (macrophages and polymorphonuclear neutrophils) were prevalent. Conclusions: The thyroid gland can be directly infected by the SARS-CoV-2. Infection strongly activates IFN pathways. The direct viral insult combined with an intense immune response may trigger or worsen thyroid conditions in predisposed individuals.

Prevalence of Delta-Like Protein 3 in a Consecutive Series of Surgically Resected Lung Neuroendocrine Neoplasms

Delta-like protein 3 (DLL3) is a protein of the Notch pathway, and it is a potential therapeutic target for high-grade lung neuroendocrine tumors (NETs), i.e., small cell lung carcinoma (SCLC) and large cell neuroendocrine carcinoma (LCNEC). However, DLL3 prevalence in lung NETs and its association with clinicopathological characteristics and prognosis remained unclear. We analyzed the immunohistochemical expression of DLL3 and its prognostic role in a consecutive series of 155 surgically resected lung NETs, including typical carcinoid (TC), atypical carcinoid (AC), LCNEC, and SCLC patients. The DLL3 expression was categorized as high (>50% positive tumor cells) or low (<50%). In addition, tumors were categorized by H-score (i.e., percentage of positive cells by staining intensity, ≥150 vs. <150). DLL3 staining was positive in 99/155 (64%) samples, and high DLL3 expression was frequently observed in high-grade tumors. In detail, 46.9% and 75% of SCLC and 48.8% and 53.7% of LCNEC specimens showed a high DLL3 expression by using H-score and percentage of positive tumor cells, respectively. Regarding low-grade NETs, only 4.9% and 12.2% TCs and 19.5% and 24.4% ACs had high DLL3 expression considering H-score and percentage of positive tumor cells, respectively. High DLL3 expression was associated with advanced American Joint Committee on Cancer (AJCC) stage, peripheral location, and chromogranin A expression in high-grade tumors (p < 0.05). In low-grade NETs, high DLL3 expression was associated with female sex, peripheral location, a higher number of mitoses, higher Ki-67 index, presence of necrosis, and pleural infiltration (p < 0.05). No association was observed between high DLL3 expression and overall survival (OS) and disease-free survival (DFS) in high-grade NETs, whereas high DLL3 expression was associated with lower DFS in ACs (p = 0.01). In conclusion, our study demonstrated a high prevalence of DLL3 expression in high-grade lung NET patients and its association with aggressive clinicopathological features. These findings confirm that DLL3 could represent a useful biomarker for target therapy in high-grade tumors. Our results also suggest that the DLL3 expression could identify a subset of AC tumors with more aggressive behavior, thus providing the basis for new therapeutic options in this group of patients.

A case of intravascular large B cell lymphoma with brain involvement mimicking progressive multifocal leukoencephalopathy

Intravascular large B-cell lymphoma (IVLBCL) is a very rare form of extranodal lymphoma, characterized by the proliferation of neoplastic B cells within the lumen of small vessels. Due to its high aggressivity, for years the prognosis had been really poor with only anectodical cases of remission after traditional chemotherapy. More recently, new therapeutic protocols allowed a significant increase in overall survival. It can virtually involve every organ, being skin and central nervous system the most affected. The clinical presentation is often unspecific and insidious; therefore, diagnosis can be challenging. Tissue biopsy, in particular random deep skin biopsy, is the gold standard for definitive diagnosis. We describe the case of a 58-year-old woman with a previous diagnosis of myelofibrosis, who presented with a rapidly progressive neurological deterioration and a brain MRI suggestive of Progressive Multifocal Leukoencephalopathy. Due to the absence of BK and JC viruses in cerebrospinal fluid and the presence of severe myalgias and subcutaneous nodules, a skin and muscle biopsy was performed, allowing diagnosis of IVLBCL. We describe the diagnostic pitfalls of this case, briefly reviewing existing literature about IVLBCL.

Biomarkers and Gene Signatures to Predict Durable Response to Pembrolizumab in Non-Small Cell Lung Cancer

Simple Summary

Not all patients with advanced or metastatic non-small cell lung cancer (NSCLC) respond to pembrolizumab, even if their tumor expresses PD-L1. This is a monocentric study aimed at identifying potential predictive biomarkers for pembrolizumab first-line treatment. Tumor microenvironment was characterized by gene expression analysis in 46 tumor samples from 25 NSCLC patients with and 21 without durable clinical benefit. As expected, patients achieving clinical benefit had a greater infiltration of immune cells. In particular, CD8 T-cell and NK cell scores were strongly associated with durable benefit. Single immune cell markers such as XCL1/2 showed a high performance in predicting durable response to pembrolizumab with an AUC of 0.85. In the same series PD-L1 expression levels had an AUC equal to 0.61. Identified predictive biomarkers can improve patients’ selection, thus optimizing treatment definition.

Abstract

Pembrolizumab has been approved as first-line treatment for advanced Non-small cell lung cancer (NSCLC) patients with tumors expressing PD-L1 and in the absence of other targetable alterations. However, not all patients that meet these criteria have a durable benefit. In this monocentric study, we aimed at refining the selection of patients based on the expression of immune genes. Forty-six consecutive advanced NSCLC patients treated with pembrolizumab in first-line setting were enrolled. The expression levels of 770 genes involved in the regulation of the immune system was analysed by the nanoString system. PD-L1 expression was evaluated by immunohistochemistry. Patients with durable clinical benefit had a greater infiltration of cytotoxic cells, exhausted CD8, B-cells, CD45, T-cells, CD8 T-cells and NK cells. Immune cell scores such as CD8 T-cell and NK cell were good predictors of durable response with an AUC of 0.82. Among the immune cell markers, XCL1/2 showed the better performance in predicting durable benefit to pembrolizumab, with an AUC of 0.85. Additionally, CD8A, CD8B and EOMES showed a high specificity (>0.86) in identifying patients with a good response to treatment. In the same series, PD-L1 expression levels had an AUC of 0.61. The characterization of tumor microenvironment, even with the use of single markers, can improve patients’ selection for pembrolizumab treatment.

Multiple Resistance Mechanisms to Tyrosine Kinase Inhibitors in EGFR Mutated Lung Adenocarcinoma: A Case Report Harboring EGFR Mutations, MET Amplification, and Squamous Cell Transformation

Resistance to EGFR tyrosin kinase inhibitors (TKI) inevitably occurs. Here it is reported the case of a young patient affected by lung adenocarcinoma harboring the L858R EGFR sensitive mutation. The patient developed multiple TKI resistance mechanisms: T790M EGFR resistance mutation, detected only on tumor cell-free DNA, squamous cell transformation and MET amplification, both detected on a tumor re-biopsy. The co-occurrence of squamous cell transformation and de novo MET amplification is an extremely rare event, and this case confirms how dynamic and heterogeneous can be the temporal and spatial tumor evolution under treatment pressure.

Fusion proteins in lung cancer: addressing diagnostic problems for deciding therapy

Introduction: Gene fusions are frequent chromosomal aberrations in solid tumors. In Lung cancer (LC) several druggable-fusions involving tyrosine kinase receptor genes have been described, including ALK, ROS1, RET and NTRK. In non-small cell lung cancer, testing for targetable fusions has become a part of routine clinical practice, greatly impacting therapeutic choice for patients with these aberrations. Although substantial technologies for gene fusion detection have been implemented over time including; cytogenetic, Fluorescence in situ hybridization (FISH), Immunohistochemistry (IHC), Retro-transcription Real-Time PCR (RT-qPCR), to Next Generation Sequencing (NGS), nCounter system (Nanostring technology), several critical issues remain. To date, only the companion diagnostic tests FISH and IHC for ALK-rearrangements and NGS for ROS1-rearrangments were approved. Other fusion approved tests are currently unavailable.Areas covered: In this review, we explore current diagnostic problems of gene fusion detection relative to the technologies available, in order to clarify future standardization of analyses which determine therapeutic choices.Expert opinion: The establishment of a gold standard, an effective diagnostic algorithm, and a standardized interpretation for the analysis of each druggable-fusions in lung cancer is essential for adequate therapeutic management.

Active metronomic vinorelbine schedules decrease plasma interleukin-2 levels in mice with Lewis lung carcinoma

The aim of our study was to investigate the effects of metronomic vinorelbine (mVNR) in a tumor model of Lewis Lung (LL) cancer in immunocompetent C57BL/6 mice, looking at the plasma levels of interleukin-2 (IL-2) and interleukin-8 (IL-8). mVNR caused a concentration-dependent antiproliferative effect in vitro on LL/2 cells. The in vivo experiment showed the significant antitumor effects of mVNR at the dose of 4 mg/Kg and 5 mg/Kg, 3 times/week, and the significant dose-dependent decrease of IL-2 concentrations in plasma samples. Conversely, such an effect was not observed for IL-8. A significant decrease in microvessel density was also found at both the active mVNR doses. In conclusion, our study confirmed the activity of mVNR in an immunocompetent model of lung carcinoma and suggest multiple mechanisms of action, including the modulation of IL-2 levels.

Pharmacological effects of vinorelbine in combination with lenvatinib in anaplastic thyroid cancer

Anaplastic thyroid cancer (ATC) is a rare neoplasia with a poor prognosis. Proliferation and apoptosis assays were performed on ATC cell lines (8305C, 8505C) exposed to vinorelbine, lenvatinib, as well as to concomitant combinations. ABCB1, ABCG2 and CSF-1 mRNA expression was evaluated by real time PCR. The relative levels of pospho Akt were investigated as part of a human phospho-kinase array analysis, and CSF-1 and VEGFR-2 protein levels were measured by ELISA. The intracellular concentration of lenvatinib in ATC cells was measured by combined reversed-phase liquid chromatography-tandem mass spectrometry. An ATC subcutaneous xenograft tumor model in nude mice was treated with vinorelbine, lenvatinib, or vinorelbine plus lenvatinib. After treatment with vinorelbine, lenvatinib, a significant antiproliferative effect in ATC cell lines was observed. The concomitant treatment of vinorelbine and lenvatinib revealed synergism for all the fractions of affected cells. A decrease in ABCB1 expression was reported in both ATC cell lines treated with the lenvatinib plus vinorelbine combination, as was an increase in the intracellular concentration of lenvatinib. The combination caused a decrease in Akt, GSK3α/β, PRAS40 and Src phosphorylation, and in both CSF-1 mRNA and protein levels. In the subcutaneous tumor model, the combination reduced the tumor volume during the treatment period. Our results establish the synergistic ATC antitumor activity of a vinorelbine and lenvatinib combination.

Synergistic activity of linifanib and irinotecan increases the survival of mice bearing orthotopically implanted human anaplastic thyroid cancer

Anaplastic thyroid cancer (ATC) is the most aggressive form of thyroid cancer, and novel combined therapies are urgently needed to prolong patient survival. No data are currently available on the preclinical activity of the combination of linifanib, a CSF-1R inhibitor, and irinotecan in ATC. The aim of the study was to evaluate the in vitro and in vivo activity of linifanib plus irinotecan. Proliferation and apoptosis assays were performed on 8305C and 8505C human ATC cell lines exposed to SN-38, the active metabolite of irinotecan, linifanib alone, and their concomitant combination. Synergism was evaluated by the combination index method. Quantification of pospho-CSF-1R levels was performed by ELISA. In vivo ATC orthotopic xenografts were treated with the single drugs, or their combination, to evaluate their impact on survival. Histology and immunohistochemistry were performed on ATC tissue samples. Both SN-38 and linifanib inhibited in vitro the proliferation of 8305C and 8505C cells in a concentration-dependent manner, whereas their concomitant treatment revealed a strong synergism in the ATC cells. A significant pro-apoptotic activity was found in both ATC cell lines treated with linifanib alone and in combination with SN-38. Moreover, linifanib significantly decreased the levels of phospho-CSF-1R after 24 h and 72 h in both 8505C and 8305C cells, and this was also observed with the concomitant administration of SN-38. In vivo, the combination of linifanib and irinotecan produced a greater survival result than either monotherapy, and resulted in a significant higher median survival. In some of the mice the combination produced a complete response with a macroscopic disappearance of the disease, as confirmed by histology. In conclusion, the synergistic ATC antitumor activity of linifanib/irinotecan combination significantly increased the survival of ATC affected mice and induced some complete responses, suggesting a potential role of this schedule in ATC patient's treatment.

Differential Diagnosis of Malignant Pleural Mesothelioma on Cytology: A Gene Expression Panel versus BRCA1-Associated Protein 1 and p16 Tests

Pleural effusions are among the first clinical manifestations of malignant pleural mesothelioma (MPM) and often constitute the only available material for diagnosis. Although an MPM diagnosis can be reliable on cytology, the reported sensitivity is low (30% to 75%). Particularly, it can be hard to discriminate epithelioid MPM, the most common histotype, from reactive mesothelial hyperplasia (MH). Currently, BRCA1-associated protein 1 (BAP1) and CDKN2A (p16), evaluated by immunohistochemistry and fluorescent in situ hybridization, respectively, are the most valuable markers to discriminate MPM and MH. Both markers have a high specificity, but their sensitivity is not always satisfying, even when used together. We have recently developed a 117-gene expression panel, based on Nanostring technology, able to differentiate epithelioid MPM from MH pleural tissues better than BAP1 and p16. Herein, we evaluated the efficacy of the same panel on an independent retrospective cohort of 23 MPM and 11 MH pleural effusions (cell blocks and smears). The overall sensitivity and specificity of the panel were equal to 0.9565 and 1, respectively. Moreover, the panel performance was compared with BAP1 and p16 on 25 cell blocks. Sensitivity levels of gene panel, BAP1 alone, p16 alone, and BAP1 plus p16 were 1, 0.5882, 0.4706, and 0.7647, respectively. Specificity was always 1. Although further validation is needed, this gene panel could really facilitate patients' management, allowing a definitive MPM diagnosis directly on pleural effusions.

Ultrastructural Localization of Histidine-rich Glycoprotein in Skeletal Muscle Fibers: Colocalization With AMP Deaminase

Histidine-rich glycoprotein (HRG) is a plasma protein synthesized by the liver. We have given the first evidence of a tissue localization of HRG demonstrating its presence in skeletal muscle, associated with the zinc enzyme AMP deaminase (AMPD1). Moreover, we have shown that muscle cells do not synthesize HRG, but they can internalize it from plasma. We have recently demonstrated by confocal laser scanning microscopy that in human skeletal muscle, HRG is mainly localized in the myofibrils, preferentially at the I-band of the sarcomere, in the sarcoplasm, and in the nuclei. Using transmission electron microscopy and immunogold analysis, we carried out this study on human and rat normal skeletal muscles with the purpose to deepen the ultrastructural localization of HRG in skeletal muscle fibers. The immunogold analysis evidenced the presence of HRG in the sarcomeres, mainly in the I-band and to a less extent in the A-band, in the heterochromatin of nuclei, and in the sarcoplasmic reticulum. The colocalization of HRG and skeletal muscle AMPD1 was also analyzed. A colabeling of HRG and AMPD1 was evident at sarcomeric, sarcoplasmic reticulum, and nuclear levels. The significance of these interesting and new results is discussed in this article.

A gene-expression-based test can outperform bap1 and p16 analyses in the differential diagnosis of pleural mesothelial proliferations

The demonstration of tissue invasion by histology is an essential criterion for the differential diagnosis of benign and malignant mesothelial proliferations. When tissue invasion cannot be identified, the use of ancillary tests is sometimes necessary. Among investigated markers, the loss of BRCA1 associated protein 1 (BAP1) protein expression and the homozygous deletion of p16 have shown 100% specificity in separating benign and malignant mesothelial lesions. However, beyond the excellent specificity of these two markers, their low sensitivity limits their clinical utility. In this context, a previous study developed and tested a novel tool for use in the differential diagnosis of malignant pleural mesothelioma (MPM) using the NanoString System and a classification algorithm. In the current study, the performance of gene classifiers were compared using BAP1 and p16 testing. p16 FISH and BAP1 immunohistochemistry were performed on the same series of 34 epithelioid MPM and 20 benign pleural lesions, which were previously analyzed by the system. The diagnostic performance of p16, BAP1 and our classification models were compared using ROC analysis. It was observed that BAP1 loss and p16 deletion were highly specific for MPM, since they were not detected in benign lesions. However, their AUC values were not completely satisfying (BAP1: 0.8235; p16: 0.7647) particularly due to their low sensitivities. As expected, combining BAP1 and p16 tests increased the diagnostic sensitivity, thus improving the AUC (0.8824). In the same series of cases, our MPM tool outperformed BAP1 and p16 tests using the 22 and 40-gene classification models (AUC 22-gene model: 0.9996; AUC 40-gene model: 0.9990). In conclusion, the present gene-expression-based classification exhibited great potential and further validation is required to support these findings in a prospective fashion, in order to provide a solid alternative for pleural proliferation diagnosis.

Chemotherapeutic and antiangiogenic drugs beyond tumor progression in colon cancer: Evaluation of the effects of switched schedules and related pharmacodynamics

The aim of the study was to evaluate the effects and the related pharmacological mechanisms of switched schedules of antiangiogenic and chemotherapeutic drugs beyond progression after a first-line treatment in a colorectal cancer preclinical model. In vivo studies were performed in nude mice subcutaneously transplanted with colon cancer cells. The treatments included drug combinations with a switch between chemotherapeutic (i.e., irinotecan and 5-fluorouracil) and/or antiangiogenic drugs (i.e., anti-VEGF antibodies and sunitinib) at the time of tumor progression. Proliferation assays were also achieved in vitro on different colon cancer cell lines exposed to SN-38 and sunitinib alone or in combination. ABCG2 gene expression was performed with real-time PCR and SN-38 intracellular concentrations were measured. The switch in the combined treatments, at the time of tumor progression, of the chemotherapeutic (from irinotecan to 5-fluoruracil), or the antiangiogenic drug (from anti-VEGF antibodies to sunitinib) or of both drugs induced a new response. Immunohistochemistry of stromal PDGF-C, PlGF, SD1-α, Tie-2, and VEGFR-2 showed statistical differences between tumors at the time of relapse and after the switched therapy. Moreover, the combination of SN-38 and sunitinib caused synergism on colon cancer cells, with significant inhibition of the ABCG2 gene expression and an increase of SN-38 intracellular concentrations. Our observations may be of clinical relevance, suggesting the switch of single chemotherapeutic or antiangiogenic drugs beyond progression of the disease to obtain a new tumor response due to a modulation of angiogenic factors and a direct effect on tumor cells with a possible variation of intracellular drug concentrations.

Malignant pleural mesothelioma and mesothelial hyperplasia: A new molecular tool for the differential diagnosis

Malignant pleural mesothelioma (MPM) is a rare asbestos related cancer, aggressive and unresponsive to therapies. Histological examination of pleural lesions is the gold standard of MPM diagnosis, although it is sometimes hard to discriminate the epithelioid type of MPM from benign mesothelial hyperplasia (MH).This work aims to define a new molecular tool for the differential diagnosis of MPM, using the expression profile of 117 genes deregulated in this tumour.The gene expression analysis was performed by nanoString System on tumour tissues from 36 epithelioid MPM and 17 MH patients, and on 14 mesothelial pleural samples analysed in a blind way. Data analysis included raw nanoString data normalization, unsupervised cluster analysis by Pearson correlation, non-parametric Mann Whitney U-test and molecular classification by the Uncorrelated Shrunken Centroid (USC) Algorithm.The Mann-Whitney U-test found 35 genes upregulated and 31 downregulated in MPM. The unsupervised cluster analysis revealed two clusters, one composed only of MPM and one only of MH samples, thus revealing class-specific gene profiles. The Uncorrelated Shrunken Centroid algorithm identified two classifiers, one including 22 genes and the other 40 genes, able to properly classify all the samples as benign or malignant using gene expression data; both classifiers were also able to correctly determine, in a blind analysis, the diagnostic categories of all the 14 unknown samples.In conclusion we delineated a diagnostic tool combining molecular data (gene expression) and computational analysis (USC algorithm), which can be applied in the clinical practice for the differential diagnosis of MPM.

The 2015 World Health Organization Classification of lung tumors: new entities since the 2004 Classification

In the last few years different new pulmonary neoplastic lesions have been recognised and some of them, namely NUT carcinoma, PEComatous tumors, pneumocytic adenomyoepithelioma, pulmonary myxoid sarcoma, myoepithelial tumors/carcinomas entered in the last 2015-WHO classification of lung tumors. In addition angiomatoid fibrous histiocytoma and ciliated muconodular papillary tumor have been morphologically and genetically characterized albeit not yet included in the 2015-WHO classification. In the present paper we summarised the clinical, morphological, immunohistochemical and molecular features of these new entities. The knowledge of key histologic and molecular characteristics may help pathologists in achieving a correct diagnosis thus leading to an adequate therapeutic approach.

Analysis of Fusion Genes by NanoString System: A Role in Lung Cytology?

CONTEXT

- Patients with non-small cell lung cancer harboring ALK receptor tyrosine kinase ( ALK), ROS proto-oncogene 1 ( ROS1), and ret proto-oncogene ( RET) gene rearrangements can benefit from specific kinase inhibitors. Detection of fusion genes is critical for determining the best treatment. Assessing rearrangements in non-small cell lung cancer remains challenging, particularly for lung cytology.

OBJECTIVE

- To examine the possible application of the multiplex, transcript-based NanoString system (NanoString Technologies, Seattle, Washington) in the evaluation of fusion genes in lung adenocarcinoma samples.

DATA SOURCES

- This study is a narrative literature review. Studies about NanoString, gene fusions, and lung adenocarcinoma were collected from PubMed (National Center for Biotechnology Information, Bethesda, Maryland). We found 7 articles about the application of the NanoString system to detect fusion genes on formalin-fixed, paraffin-embedded tumor tissues and one article evaluating the adequacy of lung cytologic specimens for NanoString gene expression analysis.

CONCLUSIONS

- To maximize the yield of molecular tests on small lung biopsies, the NanoString nCounter system has been suggested to detect fusion genes. NanoString fusion gene assays have been successfully applied on formalin-fixed, paraffin-embedded tissues. Although there are only a few studies available, the application of NanoString assays may also be feasible in lung cytology. According to available data, the NanoString system could strengthen the routine molecular characterization of lung adenocarcinoma.

The pathological and molecular diagnosis of malignant pleural mesothelioma: a literature review

Malignant pleural mesothelioma (MPM), an asbestos-induced tumor, represents significant diagnostic challenges for pathologists. Its histological diagnosis is stepwise and should be based on morphological assessment, supported by clinical and radiological findings, and supplemented with immunohistochemistry (IHC) and, more recently, molecular tests. The main diagnostic dilemmas are the differential diagnoses with benign mesothelial proliferations and other pleural malignant tumors. The present review is an update regarding the morphological, immunohistochemical, and molecular features with respect to MPM diagnosis. Data sources include a survey of the biomedical literature from PubMed (http://www.ncbi.nlm.nih.gov/pubmed) and textbooks focusing on the pathological diagnosis of MPM and associated immunohistochemical and molecular markers. The histological findings of MPM could facilitate its diagnosis and provide important prognostic information. The immunohistochemical approach should rest on the application of a panel including positive (mesothelial-related) and negative markers with greater than 80% sensitivity and specificity, which need to be selected based on morphology and clinical information. Moreover, in challenging cases, fluorescent in situ hybridization (FISH) testing for the p16 deletion and IHC to evaluate the loss of BRCA1-associated protein 1 (BAP1) expression could be useful in distinguishing benign from malignant pleural proliferations.

Molecular markers and new diagnostic methods to differentiate malignant from benign mesothelial pleural proliferations: a literature review

Malignant pleural mesothelioma (MPM) is an aggressive tumor associated with asbestos exposure. Histopathological analysis of pleural tissues is the gold standard for diagnosis; however, it can be difficult to differentiate malignant from benign pleural lesions. The purpose of this review is to describe the most important biomarkers and new diagnostic tools suggested for this differential diagnosis. There are many studies concerning the separation between MPM and benign pleural proliferations from both pleural tissues or effusions; most of them are based on the evaluation of one or few biomarkers by immunohistochemistry (IHC) or enzyme-linked immunosorbent assays (ELISAs), whereas others focused on the identification of MPM signatures given by microRNA (miRNA) or gene expression profiles as well as on the combination of molecular data and classification algorithms. None of the reported biomarkers showed adequate diagnostic accuracy, except for p16 [evaluated by fluorescent in situ hybridization (FISH)] and BAP1 (evaluated by IHC), both biomarkers are recommended by the International Mesothelioma Interest Group guidelines for histological and cytological diagnosis. BAP1 and p16 showed a specificity of 100% in discerning malignant from benign lesions because they are exclusively unexpressed or deleted in MPM. However, their sensitivity, even when used together, is not completely sufficient, and absence of their alterations cannot confirm the benign nature of the lesion. Recently, the availability of new techniques and increasing knowledge regarding MPM genetics led to the definition of some molecular panels, including genes or miRNAs specifically deregulated in MPM, that are extremely valuable for differential diagnosis. Moreover, the development of classification algorithms is facilitating the application of molecular data for clinical practice. Data regarding new diagnostic tools and MPM signatures are absolutely promising; however, before their application in clinical practice, a prospective validation is necessary, as these approaches could surely improve the differential diagnosis between malignant and benign pleural lesions.

Synergistic efficacy of irinotecan and sunitinib combination in preclinical models of anaplastic thyroid cancer

The identification of new therapeutic strategies is urgently needed for the management of patients affected by anaplastic thyroid cancer (ATC) due to their short survival and poor prognosis. Aim of the study was to determine the activity of the combination irinotecan/sunitinib on ATC cell growth in vitro and the antitumor effects in vivo. Proliferation assays were performed for 72 h on ATC cell lines exposed to the combination of SN-38, the active metabolite of irinotecan, and sunitinib. The simultaneous combination of sunitinib and SN-38, quantified by the combination index, determined a high synergism on ATC cells, increasing the intracellular concentrations of SN-38. Moreover, the synergistic combination greatly decreases the gene expression and the protein levels of vascular endothelial growth factor, colony stimulating factor 1 and ATP-binding cassette transporter G2 in ATC cells. A significant in vivo antitumor effect was observed in ATC xenografts with the simultaneous combination of irinotecan and sunitinib if compared to monotherapy. The simultaneous combination of irinotecan and sunitinib, in vitro and in vivo demonstrated a significant, synergistic ATC antitumor activity, suggesting a possible and rapid translation of this schedule into the clinics.

Squamous cell transformation and EGFR T790M mutation as acquired resistance mechanisms in a patient with lung adenocarcinoma treated with a tyrosine kinase inhibitor: A case report

The present case report describes the infrequent coexistence of squamous cell transformation and the epidermal growth factor receptor (EGFR) T790M mutation as resistance mechanisms to first line treatment with tyrosine kinase inhibitors. The patient was a 44-year-old female, diagnosed with a primitive advanced lung adenocarcinoma with bone metastases. The tumor was positive for the EGFR exon 19 deletion, therefore the patient was treated with afatinib (40 mg/day, orally) and radiotherapy for bone lesions. After 16 months, the patient developed resistance. Cytological examination of the pleural effusion confirmed an adenocarcinoma positive for the EGFR exon 19 deletion and the T790M mutation within exon 20, while a biopsy from the upper left bronchus revealed a keratinizing squamous cell carcinoma positive for the EGFR exon 19 deletion. In addition, the EGFR mutations were concomitantly detected in circulating cell-free tumour DNA. Due to the presence of the T790M mutation, the patient underwent osimertinib therapy (80 mg/day, orally), which resulted in a partial tumour regression at the 2-month follow-up, whereas the squamous lesions were treated with radiotherapy. The adenocarcinoma and squamous carcinoma components may share the same origin, according to the presence of the EGFR exon 19 deletion in both lesions. More accurate characterization of resistance mechanisms may lead to the development of improved treatment regimens.

Detection of Mycobacterium tuberculosis from paraffin-embedded tissues by GeneXpert MTB/RIF

GeneXpert MTB/RIF (Xpert) assay, a rapid and automated system based on real-time PCR and molecular beacon technology, proved to be a sensitive and specific tool capable of detecting Mycobacterium tuberculosis and rifampin resistance in clinical specimens. In this study we provide a Xpert-dedicated successful protocol for processing paraffin-embedded tissue and assess the feasibility of the Xpert assay-based tuberculosis (TB) diagnosis on these specimens, thus proving the Xpert assay as a valuable TB diagnostic tool in supporting conventional histopathological methods.

Novel prognostic markers for epithelioid malignant pleural mesothelioma

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Background: Malignant pleural mesothelioma (MPM) is a deadly asbestos related tumour. The median survival is about 12 months and MPM patients are usually offered with a multimodality approach. With regard to chemotherapy the treatment of choice is the antifolate pemetrexed in combination with cisplatin or carboplatin. The high variability in the survival of patients with similar characteristics make it challenging to identify reliable prognostic markers. In this study we sought novel prognostic markers for epithelioid MPM, by investigating the expression levels of 117 genes involved in cancer. Methods: Gene expression analysis was evaluated on RNA from 15 epithelioid MPM patients undergoing pleurectomy (fomalin-fixed paraffin-embedded tissue) using a custom panel on nanoString platform. All patients were treated with cisplatin plus pemetrexed chemotherapy. Patients were divided in two groups for each gene (high and low expression level) on the basis of median. The correlation between gene expression, overall survival (OS) and progression free survival (PFS) was carried out by Log-rank test (Kaplan Meier). Results: A poorer OS was associated with a higher expression of 3 genes: MCM2 (p-value 0.005), PLK1 (p-value 0.005) and CCNB2 (p-value 0.01). These findings were in agreement with TCGA data ( PROGgeneV2: enhancements on the existing database. BMC Cancer 2014). Moreover, PLK1 showed a significant correlation also with PFS (p-value 0.01). Conclusions: Several biomarkers have been suggested as MPM prognostic factors, but sensitive and specific ones for the clinical practice are still missing. Despite the relatively small number of tissue samples, related to the rarity of this tumour, we identified 3 genes as potential prognostic markers. MCM2 is involved in the initiation of genome replication, PLK1 and CCNB2 regulate cell cycle by promoting mitosis. All these genes proved to be not only useful prognostic indicators but also promising therapeutic targets as reported in functional studies on different cancer models. The validation of these new markers, particularly of PLK1 which is correlated also with PFS, may improve the prognostic stratification at diagnosis, providing information valuable in the management of MPM patients.

MET exon 14 mutations in advanced lung adenocarcinoma: Frequency and coexisting alterations

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Background: In lung cancer the evaluation of MET, a tyrosine kinase receptor involved in tumor growth and invasiveness, for copy number amplification and point mutations is relevant for prognosis and therapy. In lung adenocarcinoma (ADC) MET amplification is observed in 1-2% and MET mutations in 3-4% of cases. Mutations mainly occur in exon 14 (ex14), which encodes for the juxtamembrane negative regulatory domain, including splice site alterations and missense mutations within the exon.Commonly, MET ex14 alterations, in particular splice site ones, are mutually exclusive with other driver mutations, but co-occurrence with MET and MDM2 amplification and KRAS mutations was described. We evaluated METex14 mutation frequency and coexistence with additional driver alterations in a prospective cohort of Italian ADC patients. Methods: 315 ADC patients were tested (January-December 2016) for MET ex14 alterations by Sanger Sequencing on formalin-fixed paraffin-embedded tissues and cytological smears (tumor cells > 40%). MET positive cases were screened also for other oncogenes, among which KRAS, BRAF and PIK3CA, using a MALDI-TOF platform, and for ROS1 translocations and MET amplification by FISH. Results: 16 patients (5%) were MET positive: 7 splice site mutations (43%) and 9 (57%) other alterations within ex14. Among splice site mutations 1 co-occurred with ROS1 translocation and 1 with MET amplification. Among other mutations we found 5 T1010I missense mutations: 3 co-occurring with G12D/G13C/Q61H KRAS, 1 with G469A BRAF and 1 with a MET intron 13 point mutation; 2 R988C mutations: 1 with G13C KRAS and 1 with G13C KRAS plus ROS1 translocation; 1 P1026S mutation and 1 frameshift deletion (p.A991del;R992fs*999), both with G12C KRAS. Conclusions: Splice site mutations cause MET activation by exon skipping and increase sensitivity to tyrosine-kinase inhibitors, whereas how other ex14 mutations affect MET function is not fully understood. In our cohort we found a high rate of METex14 mutations together with alterations in other oncogenes, mostly KRAS. The interaction of MET with cancer signaling pathways deserve further investigation in order to better define the role of ex14 mutations in the context of target therapy.

Homeobox B9 Mediates Resistance to Anti-VEGF Therapy in Colorectal Cancer Patients

Purpose: The identification of predictive biomarkers for antiangiogenic therapies remains an unmeet need. We hypothesized that the transcription factor Homeobox B9 (HOXB9) could be responsible for the tumor resistance to the anti-VEGF agent bevacizumab.Experimental Design: HOXB9 expression and activation were measured in eight models of colorectal and pancreatic cancer with different resistance to bevacizumab. Serum levels of Angiopoietin-like Protein (Angptl)2, CXC receptor ligand (CXCL)1, IL8, and TGFβ1 in tumor-bearing mice were measured by multiplex xMAP technology. HOXB9 expression was measured by immunohistochemical analysis in 81 pretreatment specimens from metastatic colorectal cancer patients. Differences in progression-free survival (PFS) were determined using a log-rank test.Results: HOXB9-positive tumors were resistant to bevacizumab, whereas mice bearing HOXB9-negative tumors were cured by this agent. Silencing HOXB9 in bevacizumab-resistant models significantly (P < 0.05) reduced Angptl2, CXCL1, IL8, and TGFβ1 levels, reverted their mesenchymal phenotype, reduced CD11b+ cells infiltration, and restored, in turn, sensitivity to bevacizumab. HOXB9 had no prognostic value in patients treated with a first-line chemotherapeutic regimen noncontaining bevacizumab. However, patients affected by an HOXB9-negative tumor had a significantly longer PFS compared with those with an HOXB9-positive tumor if treated with a first-line regimen containing bevacizumab (18.0 months vs. 10.4 months; HR 2.037; 95% confidence interval, 1.006-4.125; P = 0.048).Conclusions: These findings integrate the complexity of numerous mechanisms of anti-VEGF resistance into the single transcription factor HOXB9. Silencing HOXB9 could be a promising approach to modulate this resistance. Our results candidate HOXB9 as predictive biomarker for selecting colorectal cancer patients for antiangiogenic therapy. Clin Cancer Res; 23(15); 4312-22. ©2017 AACR.