Association of combined PD-L1 expression and tumour-infiltrating lymphocyte features with survival and treatment outcomes in patients with metastatic melanoma.

BACKGROUND: Recent advances obtained with immune checkpoint inhibitors (ICIs) targeting the programmed cell death-1 (PD-1) protein have significantly improved the outcome of patients with metastatic melanoma. The PD-L1 expression in tumour cells as detected by immunohistochemistry is a predictive biomarker in some solid tumours, but appears insufficient as prognostic or predictive factor of response to ICIs in metastatic melanomas. OBJECTIVES: We investigated whether the presence and the features of pretreatment CD8+ tumour-infiltrating T lymphocytes (TILs) could be a complementary prognostic or predictive biomarker in patients with metastatic melanoma. METHODS: In this retrospective study, we evaluated the association of PD-L1 expression ≥5% of tumour cells combined with TIL features (CD8, CD28, Ki67) with the overall survival (OS) among 51 patients treated with ICIs and 54 patients treated with other treatment options (non-ICIs). RESULTS: PD-L1 positivity was observed in 33% and 39% of primary melanomas and matched metastases, respectively, with, however, poor concordance between the primary and the matched metastatic site (κ = 0.283). No significant association was noted between PD-L1 expression and CD8+ TIL profile analysed as single markers and OS or response to immunotherapy. Instead, their combined analysis in primary melanoma samples showed that the PD-L1-/CD8+ status was significantly associated with prolonged OS in the whole population (P = 0.04) and in the subgroup treated with non-ICIs (P = 0.009). Conversely, the PD-L1+/CD8+ status was a good prognostic factor in patients treated with ICIs (P = 0.022), whereas was significantly associated with poor prognosis in patients treated with non-ICIs (P = 0.014). While the expression of CD28 was not related to outcome, the Ki67 expression was significantly associated with poor OS in the subgroup CD8+ TIL+/PD-L1- (P = 0.02). CONCLUSIONS: The pretreatment combination of PD-L1 expression with the level of CD8+ TILs could better assess OS and predict therapeutic response of patients with metastatic melanoma treated by either immunotherapy or other treatment regimens.

Integrative and comparative genomic analyses identify clinically relevant pulmonary carcinoid groups and unveil the supra-carcinoids.

The worldwide incidence of pulmonary carcinoids is increasing, but little is known about their molecular characteristics. Through machine learning and multi-omics factor analysis, we compare and contrast the genomic profiles of 116 pulmonary carcinoids (including 35 atypical), 75 large-cell neuroendocrine carcinomas (LCNEC), and 66 small-cell lung cancers. Here we report that the integrative analyses on 257 lung neuroendocrine neoplasms stratify atypical carcinoids into two prognostic groups with a 10-year overall survival of 88% and 27%, respectively. We identify therapeutically relevant molecular groups of pulmonary carcinoids, suggesting DLL3 and the immune system as candidate therapeutic targets; we confirm the value of OTP expression levels for the prognosis and diagnosis of these diseases, and we unveil the group of supra-carcinoids. This group comprises samples with carcinoid-like morphology yet the molecular and clinical features of the deadly LCNEC, further supporting the previously proposed molecular link between the low- and high-grade lung neuroendocrine neoplasms.

New Insights on Diagnostic Reproducibility of Biphasic Mesotheliomas: A Multi-Institutional Evaluation by the International Mesothelioma Panel From the MESOPATH Reference Center.

INTRODUCTION: The 2015 WHO classification of tumors categorized malignant mesothelioma into epithelioid, biphasic (BMM), and sarcomatoid (SMM) for prognostic relevance and treatment decisions. The survival of BMM is suspected to correlate with the amount of the sarcomatoid component. The criteria for a sarcomatoid component and the interobserver variability between pathologists for identifying this component are not well described. In ambiguous cases, a "transitional" (TMM) subtype has been proposed but was not accepted as a specific subtype in the 2015 WHO classification. The aims of this study were to evaluate the interobserver agreement in the diagnosis of BMM, to determine the nature and the significance of TMM subtype, and to relate the percentage of sarcomatoid component with survival. The value of staining for BRCA-1-associated protein (BAP1) and CDKN2A(p16) fluorescence in situ hybridization (FISH) were also assessed with respect to each of the tumoral components. METHODS: The study was conducted by the International Mesothelioma Panel supported by the French National Cancer Institute, the network of rare cancer (EURACAN) and in collaboration with the International Association for the Study of Lung Cancer (IASLC). The patient cases include a random group of 42 surgical biopsy samples diagnosed as BMM with evaluation of SMM component by the French Panel of MESOPATH experts was selected from the total series of 971 BMM cases collected from 1998 to 2016. Fourteen international pathologists with expertise in mesothelioma reviewed digitally scanned slides (hematoxylin and eosin - stained and pan-cytokeratin) without knowledge of prior diagnosis or outcome. Cases with at least 7 of 14 pathologists recognizing TMM features were selected as a TMM group. Demographic, clinical, histopathologic, treatment, and follow-up data were retrieved from the MESOBANK database. BAP1 (clone C-4) loss and CDKN2A(p16) homozygous deletion (HD) were assessed by immunohistochemistry (IHC) and FISH, respectively. Kappa statistics were applied for interobserver agreement and multivariate analysis with Cox regression adjusted for age and gender was performed for survival analysis. RESULTS: The 14 panelists recorded a total of 544 diagnoses. The interobserver correlation was moderate (weighted Kappa = 0.45). Of the cases originally classified as BMM by MESOPATH, the reviewers agreed in 71% of cases (385 of 544 opinions), with cases classified as pure epithelioid in 17% (93 of 544), and pure sarcomatoid in 12% (66 of 544 opinions). Diagnosis of BMM was made on morphology or IHC alone in 23% of the cases and with additional assessment of IHC in 77% (402 of 544). The median overall survival (OS) of the 42 BMM cases was 8 months. The OS for BMM was significantly different from SMM and epithelioid malignant mesothelioma (p < 0.0001). In BMM, a sarcomatoid component of less than 80% correlated with a better survival (p = 0.02). There was a significant difference in survival between BMM with TMM showing a median survival at 6 months compared to 12 months for those without TMM (p < 0.0001). BAP1 loss was observed in 50% (21 of 42) of the total cases and in both components in 26%. We also compared the TMM group to that of more aggressive patterns of epithelioid subtypes of mesothelioma (solid and pleomorphic of our large MESOPATH cohort). The curve of transitional type was persistently close to the OS curve of the sarcomatoid component. The group of sarcomatoid, transitional, and pleomorphic mesothelioma were very close to each other. We then considered the contribution of BAP1 immunostaining and loss of CDKN2A(p16) by FISH. BAP1 loss was observed in 50% (21 of 41) of the total cases and in both component in 27% of the cases (11 of 41). There was no significant difference in BAP1 loss between the TMM and non-TMM groups. HD CDKN2A(p16) was detected in 74% of the total cases with no significant difference between the TMM and non-TMM groups. In multivariate analysis, TMM morphology was an indicator of poor prognosis with a hazard ratio = 3.2; 95% confidence interval: 1.6 - 8.0; and p = 0.003 even when compared to the presence of HD CDKN2A(p16) on sarcomatoid component (hazard ratio = 4.5; 95% confidence interval: 1.2 - 16.3, p = 0.02). CONCLUSIONS: The interobserver concordance among the international mesothelioma and French mesothelioma panel suggests clinical utility for an updated definition of biphasic mesothelioma that allows better stratification of patients into risk groups for treatment decisions, systemic anticancer therapy, or selection for surgery or palliation. We also have shown the usefulness of FISH detection of CDKN2A(p16) HD compared to BAP1 loss on the spindle cell component for the separation in ambiguous cases between benign florid stromal reaction from true sarcomatoid component of biphasic mesothelioma. Taken together our results further validate the concept of transitional pattern as a poor prognostic indicator.

Detection of PD-L1 in circulating tumor cells and white blood cells from patients with advanced non-small-cell lung cancer.

Background: Expression of PD-L1 in tumor cells and tumor-infiltrating immune cells has been associated with improved efficacy to anti-PD-1/PD-L1 inhibitors in patients with advanced-stage non-small-cell lung cancer (NSCLC) and emerged as a potential biomarker for the selection of patients to cancer immunotherapies. We investigated the utility of circulating tumor cells (CTCs) and circulating white blood cells (WBCs) as a noninvasive method to evaluate PD-L1 status in advanced NSCLC patients. Patients and methods: CTCs and circulating WBCs were enriched from peripheral blood samples (ISET® platform; Rarecells) from 106 NSCLC patients. PD-L1 expression on ISET filters and matched-tumor tissue was evaluated by automated immunostaining (SP142 antibody; Ventana), and quantified in tumor cells and WBCs. Results: CTCs were detected in 80 (75%) patients, with levels ranging from 2 to 256 CTCs/4 ml, and median of 60 CTCs/4 ml. Among 71 evaluable samples with matched-tissue and CTCs, 6 patients (8%) showed ≥1 PD-L1-positive CTCs and 11 patients (15%) showed ≥1% PD-L1-positive tumor cells in tumor tissue with 93% concordance between tissue and CTCs (sensitivity = 55%; specificity = 100%). From 74 samples with matched-tissue and circulating WBCs, 40 patients (54%) showed ≥1% PD-L1-positive immune infiltrates in tumor tissue and 39 patients (53%) showed ≥1% PD-L1 positive in circulating WBCs, with 80% concordance between blood and tissue (sensitivity = 82%; specificity = 79%). We found a trend for worse survival in patients receiving first-line cisplatin-based chemotherapy treatments, whose tumors express PD-L1 in CTCs or immune cells (progression-free and overall survival), similar to the effects of PD-L1 expression in matched-patient tumors. Conclusions: These results demonstrated that PD-L1 status in CTCs and circulating WBCs correlate with PD-L1 status in tumor tissue, revealing the potential of CTCs assessment as a noninvasive real-time biopsy to evaluate PD-L1 expression in patients with advanced-stage NSCLC.

Immunotherapy in Non-Small Cell Lung Cancer: Biological Principles and Future Opportunities.

Immunotherapy aims to amplify the anticancer immune response through reactivation of the lymphocytic response raised against several tumor neo-antigens. To obtain an effective immune response, this therapeutic approach requires that a number of immunological checkpoints be passed, such as the activation of excitatory costimulatory signals or the avoidance of coinhibitory molecules. Among the immune checkpoints, the interaction of the membrane-bound ligand PD-1 and its receptor PD-L1 has received much attention because of remarkable efficacy in numerous clinical trials for various cancer types, including non-small cell lung cancer (NSCLC). However, several limitations exist with these therapeutic agents when used as monotherapy, with objective responses observed in only 30-40% of patients, with the majority of patients demonstrating innate resistance, and approximately 25% of responders later demonstrating disease progression. Recent developments in the understanding of cancer immunology have the potential to identify mechanisms of innate and acquired resistance to immune checkpoint inhibitors through translational research in human samples. This review focuses on the biological basic principles for immunological checkpoint blockade, and highlights the current status and the perspectives of this therapeutic approach in NSCLC patients.

NF-kB2 induces senescence bypass in melanoma via a direct transcriptional activation of EZH2.

Enhancer of Zeste homologue 2 (EZH2) belongs to the polycomb repressive complex 2 and catalyzes the methylation of histone H3 lysine 27. These pivotal epigenetic marks are altered in many cancers, including melanoma, as a result of EZH2 overexpression. Here, we show that the non-canonical-NF-kB pathway accounts for most of the NF-kB activity in melanoma cells, in contrast to non-cancer cells. We identify the non-canonical-NF-kB pathway as a key regulator of EZH2 expression in melanoma. We show a striking correlation between NF-kB2 and EZH2 expression in human melanoma metastases. We demonstrate that inhibition of the non-canonical NF-kB pathway by targeting NF-kB2/p52 or the upstream kinase NIK restores the senescence program in melanoma cells through the decrease of EZH2. On the contrary, the overexpression of NF-kB2/p52 in normal human melanocytes prevents stress- and oncogene-induced senescence. Finally, we show in mouse models that the inhibition of the non-canonical NF-kB pathway restores senescence and induces a dramatic reduction in tumor growth compared with controls, thus providing potential drug targets for the re-induction of senescence in melanoma and other cancers where EZH2 is overexpressed.

Comparative study of the PD-L1 status between surgically resected specimens and matched biopsies of NSCLC patients reveal major discordances: a potential issue for anti-PD-L1 therapeutic strategies.

BACKGROUND: High expression of programmed death ligand-1 (PD-L1) on tumor cells (TC) and/or on tumor-infiltrating immune cells (IC) is associated with a high response rate in patients with advanced nonsmall-cell lung cancer (NSCLC) treated with PD-L1 inhibitors. The use of a PD-L1 immunohistochemical (IHC) test in determining the responsiveness to immunotherapy has raised the question of the reliability and reproducibility of its evaluation in lung biopsies compared with corresponding resected surgical specimens. PATIENTS AND METHODS: PD-L1 expression in TC and IC was assessed in 160 patients with operable NSCLC on both whole surgical tissue sections and matched lung biopsies, by using a highly sensitive SP142 IHC assay. The specimens were scored as TC 0-3 and IC 0-3 based on increasing PD-L1 expression. RESULTS: PD-L1 expression was frequently discordant between surgical resected and matched biopsy specimens (the overall discordance rate = 48%; 95% confidence interval 4.64-13.24) and κ value was equal to 0.218 (poor agreement). In all cases, the biopsy specimens underestimated the PD-L1 status observed on the whole tissue sample. PD-L1-positive IC tumors were more common than PD-L1-positive TC tumors on resected specimens. The discrepancies were mainly related to the lack of a PD-L1-positive IC component in matched biopsies. CONCLUSIONS: Our results indicate relatively poor association of the PD-L1 expression in TC and IC between lung biopsies and corresponding resected tumors. Although these results need to be further validated in larger cohorts, they indicate that the daily routine evaluation of the PD-L1 expression in diagnostic biopsies can be misleading in defining the sensitivity to treatment with PD-L1 targeted therapy.

Why and how immunohistochemistry should now be used to screen for the BRAFV600E status in metastatic melanoma? The experience of a single institution (LCEP, Nice, France).

BACKGROUND: Knowledge of the BRAFV600E status is mandatory in metastatic melanoma patients (MMP). Molecular biology is currently the gold standard method for status assessment. OBJECTIVES: We assessed and compared the specificity, sensibility, cost-effectiveness and turnaround time (TAT) of immunohistochemistry (IHC) and molecular biology for detection of the BRAFV600E mutation in 188 MMP. METHODS: IHC, with the VE1 antibody, and pyrosequencing analysis were performed with formalin fixed paraffin embedded tumour samples. RESULTS: The BRAFV600E mutation was detected by pyrosequencing in 91/188 (48%) patients. IHC was strongly positive (3+) in all of these 91 cases. IHC was strongly positive in 9/188 (5%) cases in which the molecular testing failed due to non-amplifiable DNA. Weak or moderate staining was noted in 10/188 (5%) cases in which the molecular biology identified BRAF wild-type tumours. The ratio of the global cost for IHC/molecular biology testing was 1 : 2.2. The average TAT was 48 h vs. 96 h, for IHC vs. molecular biology testing, respectively. CONCLUSIONS: This study showed that VE1 IHC should be a substitute for molecular biology in the initial assessment of the BRAFV600E status in MPP. This methodology needs to be set up in pathology laboratories in accordance with quality control/quality assurance accreditation procedures. Under these strict conditions the question is to know if BRAFV600E-IHC can serve not only as a prescreening tool, but also as a stand-alone test (at least in cases displaying an unequivocally staining pattern) as well as an alternative predictive test for samples for which the molecular biology failed.

KRAS Mutations in Lung Adenocarcinoma: Molecular and Epidemiological Characteristics, Methods for Detection, and Therapeutic Strategy Perspectives.

KRAS mutations are detected in over one third of lung adenocarcinomas, most frequently in Caucasian and smoker patients. The impact of KRAS mutations on lung adenocarcinoma prognosis is currently subject to debate, as is their impact on the response to chemotherapy and EGFR tyrosine kinase inhibitors. The different methods for KRAS status assessment, based on histological and cytological samples or biological fluids, offer varying sensitivities. Since no treatments are available in clinical routine for KRAS-mutated lung cancer patients, one of the current major challenges in thoracic oncology is developing new dedicated strategic therapies. Different molecules can be developed that act on a post-transcriptional KRAS protein level, blocking its cytoplasmic membrane recruitment. The efficacy of these molecules' targeting of the different signaling pathways activated by the KRAS mutation (such as the MEK and BRAF pathways) is related to the particular KRAS mutation subtype. New therapeutic strategies are currently focused on certain genes linked with KRAS inducing a synthetic lethal interaction. The purpose of this work is to provide an overview of i) the recent epidemiological and molecular findings concerning KRASmutated lung adenocarcinoma, ii) the prognostic impact of KRAS mutations, in particular during response to treatment, iii) the available methods for detecting this mutation, and iv) the current molecules under development for new therapeutic strategies and the clinical trials targeting this genomic alteration.

Discrepancies between FISH and immunohistochemistry for assessment of the ALK status are associated with ALK 'borderline'-positive rearrangements or a high copy number: a potential major issue for anti-ALK therapeutic strategies.

BACKGROUND: Patients with advanced lung adenocarcinomas expressing ALK rearrangements are highly responsive to crizotinib, a dual ALK/c-MET inhibitor. Immunohistochemistry (IHC) is an easy clinically and routinely applicable cost-effective assay for ALK, c-MET and ROS1 protein expression for potential treatment with crizotinib. The purpose of this study was to evaluate the percentage and the pattern of ALK-rearranged cells, the variation in the native ALK copy number, as well as ALK, c-MET and ROS1 protein expression, and their significance on outcome of crizotinib-treated lung adenocarcinoma patients. PATIENTS AND METHODS: Consecutive lung adenocarcinoma specimens (n = 176) 'double-negative' (wild-type EGFR and KRAS) were tested for ALK rearrangements/copy number alterations and for ALK, c-MET and ROS1 protein expression using automated standardized protocols. Preliminary data on the outcome of crizotinib-treated patients were recorded. RESULTS: FISH analysis identified 26/176 (15%) cases with ALK rearrangements. Seven cases had discordant results between the ALK FISH and IHC. Five cases with discordant FISH-positive/IHC-negative revealed FISH 'borderline' positivity (15%-20%). Three cases overexpressed c-MET and responded to crizotinib, and two cases with ALK-'borderline' rearranged cells only, not associated with c-MET expression, progressed under crizotinib. Two cases with discordant FISH-negative/IHC-positive revealed ALK gene amplification without associated c-MET or ROS1 protein expression. CONCLUSIONS: The discrepancies observed between the IHC and FISH data revealed unexpected biological events, rather than technical issues, which potentially can have a strong impact on the therapeutic strategy with crizotinib.

Detection of circulating tumor cells from lung cancer patients in the era of targeted therapy: promises, drawbacks and pitfalls.

Interest in biomarkers in the field of thoracic oncology is focused on the search for new robust tests for diagnosis (in particular for screening), prognosis and theragnosis. These biomarkers can be detected in tissues and/or cells, but also in biological fluids, mainly the blood. In this context, there is growing interest in the detection of circulating tumor cells (CTCs) in the blood of lung cancer patients since CTC identification, enumeration and characterization may have a direct impact on diagnosis, prognosis and theragnosis in the daily clinical practice. Many direct and indirect methods have been developed to detect and characterize CTCs in lung cancer patients. However, these different approaches still hold limitations and many of them have demonstrated unequal sensitivity and specificity. Indeed, these methods hold advantages but also certain disadvantages. Therefore, despite the promises, it is currently difficult and premature to apply this methodology to the routine care of lung cancer patients. This situation is the consequence of the analysis of the methodological approaches for the detection and characterization of CTCs and of the results published to date. Finally, the advent of targeted cancer therapies in thoracic oncology has stimulated considerable interest in non-invasive detection of genomic alterations in tumors over time through the analysis of CTCs, an approach that may help clinicians to optimize therapeutic strategies for lung cancer patients. We describe here the main methods for CTC detection, the advantages and limitations of these different approaches and the potential usefulness and value of CTC characterization in the field of thoracic oncology.

[The French mesothelioma network from 1998 to 2013]. / Mésothéliome: les dispositifs en place en France « le réseau mésothéliome ¼ 1998-2013.

Mesothelioma is a rare disease less than 0.3% of cancers in France, very aggressive and resistant to the majority of conventional therapies. Asbestos exposure is nearly the only recognized cause of mesothelioma in men observed in 80% of case. In 1990, the projections based on mortality predicted a raise of incidence in mesothelioma for the next three decades. Nowadays, the diagnosis of this cancer is based on pathology, but the histological presentation frequently heterogeneous, is responsible for numerous pitfalls and major problems of early detection toward effective therapy. Facing such a diagnostic, epidemiological and medico-legal context, a national and international multidisciplinary network has been progressively set up in order to answer to epidemiological survey, translational or academic research questions. Moreover, in response to the action of the French Cancer Program (action 23.1) a network of pathologists was organized for expert pathological second opinion using a standardized procedure of certification for mesothelioma diagnosis. We describe the network organization and show the results during this last 15years period of time from 1998-2013. These results show the major impact on patient's management, and confirm the interest of this second opinion to provide accuracy of epidemiological data, quality of medico-legal acknowledgement and accuracy of clinical diagnostic for the benefit of patients. We also show the impact of these collaborative efforts for creating a high quality clinicobiological, epidemiological and therapeutic data collection for improvement of the knowledge of this dramatic disease.

Clinical value of circulating endothelial cells and of soluble CD146 levels in patients undergoing surgery for non-small cell lung cancer.

BACKGROUND: Previous studies indicate that endothelial injury, as demonstrated by the presence of circulating endothelial cells (CECs), may predict clinical outcome in cancer patients. In addition, soluble CD146 (sCD146) may reflect activation of angiogenesis. However, no study has investigated their combined clinical value in patients undergoing resection for non-small cell lung cancer (NSCLC). METHODS: Data were collected from preoperative blood samples from 74 patients who underwent resection for NSCLC. Circulating endothelial cells were defined, using the CellSearch Assay, as CD146+CD105+CD45-DAPI+. In parallel, sCD146 was quantified using an ELISA immunoassay. These experiments were also performed on a group of 20 patients with small-cell lung cancer, 60 healthy individuals and 23 patients with chronic obstructive pulmonary disease. RESULTS: The CEC count and the plasma level of sCD146 were significantly higher in NSCLC patients than in the sub-groups of controls (P<0.001). Moreover, an increased CEC count was associated with higher levels of sCD146 (P=0.010). Both high CEC count and high sCD146 plasma level at baseline significantly correlated with shorter progression-free survival (P<0.001, respectively) and overall survival (P=0.005; P=0.009) of NSCLC patients. CONCLUSIONS: The present study provides supportive evidence to show that both a high CEC count and a high sCD146 level at baseline correlate with poor prognosis and may be useful for the prediction of clinical outcome in patients undergoing surgery for NSCLC.

Usefulness of ancillary methods for diagnosis, prognosis and targeted therapy in thyroid pathology.

The development of molecular analyses for thyroid pathologies is on going. These analyses provide new diagnostic tools with the aim of accurately distinguishing malignant and benign thyroid tumors. They are particularly useful as most of them can be done preoperatively on thyroid fine-needle aspiration biopsy samples. Furthermore, molecular biomarkers may play a promising role since they are able to predict the prognosis of patients with thyroid tumors. Moreover, identification of molecular markers as well as a better understanding of thyroid carcinogenesis will help develop innovative targeted therapies, particularly in patients with metastatic iodo-resistant thyroid carcinoma. To date, four types of somatic genetic alterations are known to hold potential interest for the diagnosis and/or prognosis of follicular cell-derived thyroid carcinomas: BRAF and RAS mutations, and RET/PTC and PAX8/PPARγ rearrangements. Other recent molecular biomarkers have been investigated in thyroid oncology, in particular different microRNA signatures. This review describes the different aspects of ancillary methods, including those bassed on molecular biology, that are of current interest for the diagnosis, prognosis and treatment of follicular cell-derived thyroid carcinomas.

Diagnostic value of immunohistochemistry for the detection of the BRAFV600E mutation in primary lung adenocarcinoma Caucasian patients.

BACKGROUND: Non-small-cell lung carcinoma (NSCLC) patients with a BRAF(V600E) mutation benefit from targeted therapy. The usefulness of immunohistochemistry (IHC) as an alternative approach for the detection of BRAF(V600E) in NSCLC patients has not been evaluated until now. This study compared the specificity and sensitivity of IHC with other methods for the detection of BRAF(V600E) in primary lung adenocarcinoma. PATIENTS AND METHODS: BRAF mutations were analysed by DNA sequencing of a Caucasian subpopulation of selected 450 of 1509 (30%) EGFR, KRAS, PI3KA, Her2 and EML4-ALK wild-type (wt) primary lung adenocarcinomas. Detection of the BRAF(V600E) mutation was carried out by IHC using the VE1 clone antibody and compared with the results of other molecular methodologies. RESULTS: Of 450 (9%) of tumours, 40 harboured a BRAF mutation, which corresponded to either a BRAF(V600E) or a non-BRAF(V600E) mutation in 21 of 450 (5%) and 19 of 450 (4%) cases, respectively. The IHC VE1 assay was positive in 19 of 21 (90%) BRAF(V600E)-mutated tumours and negative in all BRAF(nonV600E)-mutated tumours. CONCLUSION: IHC using the VE1 clone is a specific and sensitive method for the detection of BRAF(V600E) and may be an alternative to molecular biology for the detection of mutations in NSCLC.

ALK-gene rearrangement: a comparative analysis on circulating tumour cells and tumour tissue from patients with lung adenocarcinoma.

BACKGROUND: A subgroup of anaplastic lymphoma kinase (ALK)-rearranged lung tumours can respond to ALK inhibitors. Until now, the ALK status in circulating tumour cells (CTCs) isolated from patients with lung cancer has not been characterised. We assessed the ALK status in CTCs detected in patients with lung cancer and correlated the results to the ALK status defined in the corresponding tumour tissue. PATIENTS AND METHODS: A total of 87 patients with lung adenocarcinoma showing CTCs isolated using the isolation by size of epithelial tumour cell method were screened for their ALK status both in tumour samples and in CTCs. ALK break-apart fluorescence in situ hybridisation (FISH) and immunoreactivity analyses using an anti-ALK antibody (5A4 clone) were carried out on CTCs and compared with the results obtained in the corresponding tissue specimens. RESULTS: A total of five patients showed ALK-gene rearrangement and strong ALK protein expression in CTCs and in the corresponding tumour samples. Both ALK-FISH and ALK immunoreactivity analyses show negative results in CTCs and corresponding tumour samples for 82 patients. Conclusions We demonstrated that the ALK status can be determined in CTCs isolated from patients with lung cancer by immunocytochemistry and FISH analyses. These results favour non-invasive, ALK-gene status pre-screening on a routine basis on CTCs isolated from patients with lung cancer and open new avenues for real-time monitoring for adapted targeted therapy.

Immunohistochemistry to identify EGFR mutations or ALK rearrangements in patients with lung adenocarcinoma.

BACKGROUND: Immunohistochemistry has been proposed as a specific and sensitive method to identify EGFR mutations or ALK rearrangements in lung tumours. PATIENTS AND METHODS: We assessed EGFR and KRAS by direct sequencing in 154 patients with lung adenocarcinoma. ALK rearrangements were assayed by FISH and RT-PCR. Immunohistochemistry was carried out and evaluated closely following published methods using recommended monoclonal rabbit or mouse antibodies. RESULTS: Thirteen of 36 exon 19 EGFR-mutated tumours (36%)-including 12 of 22 with p.Glu746_Ala750del (55%)-were positive with the 6B6 antibody that was raised against p.Glu746_Ala750del. One hundred eleven of 114 EGFR exon 19 wild-type tumours (97%) were negative with 6B6. Four of 21 exon 21 EGFR-mutated tumours (19%)-including 4 of 17 with p.Leu858Arg (24%)-were positive with the 43B2 antibody that was raised against p.Leu858Arg. One hundred twenty-two of 124 (98%) EGFR exon 21 wild-type tumours were negative with 43B2. Two of four ALK rearrangements-including two of three with ELM4-ALK fusion transcripts-were identified with the 5A4 antibody. Eleven of 13 tumours without ALK rearrangement (85%) were negative with 5A4. CONCLUSIONS: Immunohistochemistry is a specific means for identification of EGFR mutations and ALK rearrangements. It suffers, however, from poor sensitivity.

Hypoxia and MITF control metastatic behaviour in mouse and human melanoma cells.

Melanomas are very aggressive neoplasms with notorious resistance to therapeutics. It was recently proposed that the remarkable phenotypic plasticity of melanoma cells allows for the rapid development of both resistance to chemotherapeutic drugs and invasive properties. Indeed, the capacity of melanoma cells to form distant metastases is the main cause of mortality in melanoma patients. Therefore, the identification of the mechanism controlling melanoma phenotype is of paramount importance. In the present report, we show that deletion of microphthalmia-associated transcription factor (MITF), the master gene in melanocyte differentiation, is sufficient to increase the metastatic potential of mouse and human melanoma cells. MITF silencing also increases fibronectin and Snail, two mesenchymal markers that might explain the increased invasiveness in vitro and in vivo. Furthermore, ablation of this population by Forskolin-induced differentiation or MITF-forced expression significantly decreases tumour and metastasis formation, suggesting that eradication of low-MITF cells might improve melanoma treatment. Moreover, we demonstrate that a hypoxic microenvironment decreases MITF expression through an indirect, hypoxia-inducible factor 1 (HIF1)α-dependant transcriptional mechanism, and increases the tumourigenic and metastatic properties of melanoma cells. We identified Bhlhb2, a new factor in melanoma biology, as the mediator of hypoxia/HIF1α inhibitory effect on MITF expression. Our results reveal a hypoxia-HIF1α-BHLHB2-MITF cascade controlling the phenotypic plasticity in melanoma cells and favouring metastasis development. Targeting this pathway might be helpful in the design of new anti-melanoma therapies.