RET Fusion Testing in Patients With NSCLC: The RETING Study.

Introduction: RET inhibitors with impressive overall response rates are now available for patients with NSCLC, yet the identification of RET fusions remains a difficult challenge. Most guidelines encourage the upfront use of next-generation sequencing (NGS), or alternatively, fluorescence in situ hybridization (FISH) or reverse transcriptase-polymerase chain reaction (RT-PCR) when NGS is not possible or available. Taken together, the suboptimal performance of single-analyte assays to detect RET fusions, although consistent with the notion of encouraging universal NGS, is currently widening some of the clinical practice gaps in the implementation of predictive biomarkers in patients with advanced NSCLC. Methods: This situation prompted us to evaluate several RET assays in a large multicenter cohort of RET fusion-positive NSCLC (n = 38) to obtain real-world data. In addition to RNA-based NGS (the criterion standard method), all positive specimens underwent break-apart RET FISH with two different assays and were also tested by an RT-PCR assay. Results: The most common RET partners were KIF5B (78.9%), followed by CCDC6 (15.8%). The two RET NGS-positive but FISH-negative samples contained a KIF5B(15)-RET(12) fusion. The three RET fusions not identified with RT-PCR were AKAP13(35)-RET(12), KIF5B(24)-RET(9) and KIF5B(24)-RET(11). All three false-negative RT-PCR cases were FISH-positive, exhibited a typical break-apart pattern, and contained a very high number of positive tumor cells with both FISH assays. Signet ring cells, psammoma bodies, and pleomorphic features were frequently observed (in 34.2%, 39.5%, and 39.5% of tumors, respectively). Conclusions: In-depth knowledge of the advantages and disadvantages of the different RET testing methodologies could help clinical and molecular tumor boards implement and maintain sensible algorithms for the rapid and effective detection of RET fusions in patients with NSCLC. The likelihood of RET false-negative results with both FISH and RT-PCR reinforces the need for upfront NGS in patients with NSCLC.

Impact of Molecular Testing Using Next-Generation Sequencing in the Clinical Management of Patients with Non-Small Cell Lung Cancer in a Public Healthcare Hospital.

Next-generation sequencing (NGS) is a molecular approach able to provide a comprehensive molecular profile of non-small cell lung cancer (NSCLC). The broad spectrum of biomarker-guided therapies has positioned molecular diagnostic laboratories as a central component of patient clinical management. Here, we show the results of an UNE-EN ISO 15189:2022 NGS-accredited assay in a cohort of 350 patients. TP53 (51.0%), KRAS (26.6%) and EGFR (12.9%) were the most frequently mutated genes. Furthermore, we detected co-occurring and mutually exclusive alterations, as well as distinct molecular profiles according to sex and smoking habits. Actionable genetic alterations were significantly more frequent in female patients (80.5%, p < 0.001) and in never-smoker patients (87.7%, p < 0.001). When NGS was established as the main molecular testing strategy, 36.4% of patients received at least one line of targeted treatment. Among 200 patients with stage IV NSCLC, first-line treatment with targeted therapies was associated with a longer progression-free survival (PFS) (13.4 months (95% CI, 10.2-16.6) (p = 0.001)). Similarly, the overall survival (OS) of patients receiving at least one targeted drug was significantly longer (26.2 months (95% CI, 11.8-40.5) (p < 0.001)). Our results show that the implementation of NGS in the public healthcare system has provided a broader application of precision medicine.

Technical Validation and Clinical Implications of Ultrasensitive PCR Approaches for EGFR-Thr790Met Mutation Detection in Pretreatment FFPE Samples and in Liquid Biopsies from Non-Small Cell Lung Cancer Patients.

In pretreatment tumor samples of EGFR-mutated non-small cell lung cancer (NSCLC) patients, EGFR-Thr790Met mutation has been detected in a variable prevalence by different ultrasensitive assays with controversial prognostic value. Furthermore, its detection in liquid biopsy (LB) samples remains challenging, being hampered by the shortage of circulating tumor DNA (ctDNA). Here, we describe the technical validation and clinical implications of a real-time PCR with peptide nucleic acid (PNA-Clamp) and digital droplet PCR (ddPCR) for EGFR-Thr790Met detection in diagnosis FFPE samples and in LB. Limit of blank (LOB) and limit of detection (LOD) were established by analyzing negative and low variant allele frequency (VAF) FFPE and LB specimens. In a cohort of 78 FFPE samples, both techniques showed an overall agreement (OA) of 94.20%. EGFR-Thr790Met was detected in 26.47% of cases and was associated with better progression-free survival (PFS) (16.83 ± 7.76 vs. 11.47 ± 1.83 months; p = 0.047). In LB, ddPCR was implemented in routine diagnostics under UNE-EN ISO 15189:2013 accreditation, increasing the detection rate of 32.43% by conventional methods up to 45.95%. During follow-up, ddPCR detected EGFR-Thr790Met up to 7 months before radiological progression. Extensively validated ultrasensitive assays might decipher the utility of pretreatment EGFR-Thr790Met and improve its detection rate in LB studies, even anticipating radiological progression.

Utility of Next-Generation Sequencing in the Reconstruction of Clonal Architecture in a Patient with an EGFR Mutated Advanced Non-Small Cell Lung Cancer: A Case Report.

EGFR tyrosine kinase inhibitors (EGFR-TKIs) have revolutionized the treatment of non-small cell lung cancer (NSCLC) patients with activating EGFR mutations. However, targeted therapies impose a strong selective pressure against the coexisting tumor populations that lead to the emergence of resistant clones. Molecular characterization of the disease is essential for the clinical management of the patient, both at diagnosis and after progression. Next-generation sequencing (NGS) has been established as a technique capable of providing clinically useful molecular profiling of the disease in tissue samples and in non-invasive liquid biopsy samples (LB). Here, we describe a case report of a patient with metastatic NSCLC harboring EGFR mutation who developed two independent resistance mechanisms (EGFR-T790M and TP53 + RB1 mutations) to dacomitinib. Osimertinib given as a second-line treatment eliminated the EGFR-T790M population and simultaneously consolidated the proliferation of the TP53 + RB1 clone that eventually led to the histologic transformation to small-cell lung cancer (SCLC). Comprehensive NGS profiling revealed the presence of the TP53 + RB1 clone in the pretreatment biopsy, while EGFR-T790M was only detected after progression on dacomitinib. Implementation of NGS studies in routine molecular diagnosis of tissue and LB samples provides a more comprehensive view of the clonal architecture of the disease in order to guide therapeutic decision-making.

Molecular diagnosis in non-small-cell lung cancer: expert opinion on ALK and ROS1 testing.

The effectiveness of targeted therapies with tyrosine kinase inhibitors in non-small-cell lung cancer (NSCLC) depends on the accurate determination of the genomic status of the tumour. For this reason, molecular analyses to detect genetic rearrangements in some genes (ie, ALK, ROS1, RET and NTRK) have become standard in patients with advanced disease. Since immunohistochemistry is easier to implement and interpret, it is normally used as the screening procedure, while fluorescence in situ hybridisation (FISH) is used to confirm the rearrangement and decide on ambiguous immunostainings. Although FISH is considered the most sensitive method for the detection of ALK and ROS1 rearrangements, the interpretation of results requires detailed guidelines. In this review, we discuss the various technologies available to evaluate ALK and ROS1 genomic rearrangements using these techniques. Other techniques such as real-time PCR and next-generation sequencing have been developed recently to evaluate ALK and ROS1 gene rearrangements, but some limitations prevent their full implementation in the clinical setting. Similarly, liquid biopsies have the potential to change the treatment of patients with advanced lung cancer, but further research is required before this technology can be applied in routine clinical practice. We discuss the technical requirements of laboratories in the light of quality assurance programmes. Finally, we review the recent updates made to the guidelines for the determination of molecular biomarkers in patients with NSCLC.

Correction: Pardo-Sánchez et al. Increased Tumor Growth Rate and Mesenchymal Properties of NSCLC-Patient-Derived Xenograft Models during Serial Transplantation. Cancers 2021, 13, 2980.

The authors would like to make a correction to their published paper [...].

Increased Tumor Growth Rate and Mesenchymal Properties of NSCLC-Patient-Derived Xenograft Models during Serial Transplantation.

Non-small-cell lung cancer (NSCLC) is the leading cause of cancer death worldwide. The high mortality is very often a consequence of its late diagnosis when the cancer is already locally advanced or has disseminated. Advances in the study of NSCLC tumors have been achieved by using in vivo models, such as patient-derived xenografts. Apart from drug screening, this approach may also be useful for study of the biology of the tumors. In the present study, surgically resected primary lung cancer samples (n = 33) were implanted in immunodeficient mice, and nine were engrafted successfully, including seven adenocarcinomas, one squamous-cell carcinoma, and one large-cell carcinoma. ADC tumors bearing the KRAS-G12C mutation were the most frequently engrafted in our PDX collection. Protein expression of vimentin, ezrin, and Ki67 were evaluated in NSCLC primary tumors and during serial transplantation by immunohistochemistry, using H-score. Our data indicated a more suitable environment for solid adenocarcinoma, compared to other lung tumor subtypes, to grow and preserve its architecture in mice, and a correlation between higher vimentin and ezrin expression in solid adenocarcinomas. A correlation between high vimentin expression and lung adenocarcinoma tumors bearing KRAS-G12C mutation was also observed. In addition, tumor evolution towards more proliferative and mesenchymal phenotypes was already observed in early PDX tumor passages. These PDX models provide a valuable platform for biomarker discovery and drug screening against tumor growth and EMT for lung cancer translational research.

Development, Implementation and Assessment of Molecular Diagnostics by Next Generation Sequencing in Personalized Treatment of Cancer: Experience of a Public Reference Healthcare Hospital.

The establishment of precision medicine in cancer patients requires the study of several biomarkers. Single-gene testing approaches are limited by sample availability and turnaround time. Next generation sequencing (NGS) provides an alternative for detecting genetic alterations in several genes with low sample requirements. Here we show the implementation to routine diagnostics of a NGS assay under International Organization for Standardization (UNE-EN ISO 15189:2013) accreditation. For this purpose, 106 non-small cell lung cancer (NSCLC) and 102 metastatic colorectal cancer (mCRC) specimens were selected for NGS analysis with Oncomine Solid Tumor (ThermoFisher). In NSCLC the most prevalently mutated gene was TP53 (49%), followed by KRAS (31%) and EGFR (13%); in mCRC, TP53 (50%), KRAS (48%) and PIK3CA (16%) were the most frequently mutated genes. Moreover, NGS identified actionable genetic alterations in 58% of NSCLC patients, and 49% of mCRC patients did not harbor primary resistance mechanisms to anti-EGFR treatment. Validation with conventional approaches showed an overall agreement >90%. Turnaround time and cost analysis revealed that NGS implementation is feasible in the public healthcare context. Therefore, NGS is a multiplexed molecular diagnostic tool able to overcome the limitations of current molecular diagnosis in advanced cancer, allowing an improved and economically sustainable molecular profiling.

Assessment of a New ROS1 Immunohistochemistry Clone (SP384) for the Identification of ROS1 Rearrangements in Patients with Non-Small Cell Lung Carcinoma: the ROSING Study.

INTRODUCTION: The ROS1 gene rearrangement has become an important biomarker in NSCLC. The College of American Pathologists/International Association for the Study of Lung Cancer/Association for Molecular Pathology testing guidelines support the use of ROS1 immunohistochemistry (IHC) as a screening test, followed by confirmation with fluorescence in situ hybridization (FISH) or a molecular test in all positive results. We have evaluated a novel anti-ROS1 IHC antibody (SP384) in a large multicenter series to obtain real-world data. METHODS: A total of 43 ROS1 FISH-positive and 193 ROS1 FISH-negative NSCLC samples were studied. All specimens were screened by using two antibodies (clone D4D6 from Cell Signaling Technology and clone SP384 from Ventana Medical Systems), and the different interpretation criteria were compared with break-apart FISH (Vysis). FISH-positive samples were also analyzed with next-generation sequencing (Oncomine Dx Target Test Panel, Thermo Fisher Scientific). RESULTS: An H-score of 150 or higher or the presence of at least 70% of tumor cells with an intensity of staining of 2+ or higher by the SP384 clone was the optimal cutoff value (both with 93% sensitivity and 100% specificity). The D4D6 clone showed similar results, with an H-score of at least 100 (91% sensitivity and 100% specificity). ROS1 expression in normal lung was more frequent with use of the SP384 clone (p < 0.0001). The ezrin gene (EZR)-ROS1 variant was associated with membranous staining and an isolated green signal FISH pattern (p = 0.001 and p = 0.017, respectively). CONCLUSIONS: The new SP384 ROS1 IHC clone showed excellent sensitivity without compromising specificity, so it is another excellent analytical option for the proposed testing algorithm.

Early radiological response as predictor of overall survival in non-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor mutations.

BACKGROUND: Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKI) are the standard treatment of advanced, EGFR-mutant non-small-cell lung cancer (NSCLC). Usually, radiographic assessment of response to chemotherapy is performed after the patient completes the second course of treatment. The optimal timing of response evaluation for patients receiving EGFR-TKIs is, however, not well-defined. The purpose of this study is to evaluate the association of an early radiological response (ERR) to TKIs by computed tomography (CT) with progression-free survival (PFS) and overall survival (OS) in advanced NSCLC patients with EGFR mutations. METHODS: EGFR mutation status was analyzed retrospectively in a cohort of 360 NSCLC patients' between January 2009 and November 2014. Forty of them received treatment with TKI and therefore were included in the study. Response to TKI therapy was defined according to Response Evaluation Criteria in Solid Tumors (RECIST) v1.1. ERR was defined as complete response (CR) or partial response (PR) at the first radiographic evaluation performed within 6-8 weeks after the beginning of the treatment. RESULTS: Activating mutations in the tyrosine kinase domain of the EGFR gene were mainly exon 19 deletions. Thirty patients (75%) had ERR, 4 of those patients (10%) showed a PR on early CT achieving a CR in the long-term monitoring. Median PFS was longer in patients experiencing an ERR (10.9 vs. 2.4 months; HR: 0.42; 95% CI: 0.19-0.93; P=0.033) than those that did not [stable disease (SD) or progressive disease (PD)]. Median overall survival OS was also significantly increased in patients experiencing ERR (23.2 vs. 11.9 months; HR: 0.3; 95% CI: 0.15-0.85; P=0.021). CONCLUSIONS: ERR in patients treated with EGFR TKI therapy is associated with statistically significant PFS and OS, and could be a surrogate marker of efficacy in these patients. Moreover, ERR provides an early identification of patients not benefitting from TKI, despite the presence of activating EGFR mutations in which further efforts are needed to improve their prognosis.

Salvage therapy with topical posaconazole in lung transplant recipients with invasive Scedosporium infection.

Scedosporium is an important pathogen in cystic fibrosis (CF) and post-transplantation, but it rarely causes invasive infection. Treatment remains challenging, particularly due to the inherent resistance to multiple antifungal agents. We present 3 complicated invasive tracheobronchial and lung Scedosporium apiospermum infections following lung transplantation. In 2 of 3 cases, the infection was clinically and radiologically cured with frequent cleansing bronchoscopies, combining triazole with terbinafine therapy and nebulized posaconazole. These cases highlight the importance of adjunctive nebulized therapy in addition to prolonged triazole treatment to manage complex invasive Scedosporium infections in immunosuppressed patients. Posaconazole (PSZ) was delivered during the bronchoscopy procedure through intrabronchial administration, whereas an eFlow rapid® device was used for nebulized therapy. Topical posaconazole was well tolerated in 2 patients, with only a slight cough during administrations; the third patient had local irritation with poor tolerance, which led to its withdrawal. This is the first report on compassionate use of topical PSZ as salvage therapy for resistant mold infections in lung transplant recipients. These 3 cases represent the entire experience using this approach; no additional patients have received this therapy due to there not having been any additional cases of Scedosporium tracheobronchitis presented.

Netrin-1 receptor antibodies in thymoma-associated neuromyotonia with myasthenia gravis.

OBJECTIVE: To identify cell-surface antibodies in patients with neuromyotonia and to describe the main clinical implications. METHODS: Sera of 3 patients with thymoma-associated neuromyotonia and myasthenia gravis were used to immunoprecipitate and characterize neuronal cell-surface antigens using reported techniques. The clinical significance of antibodies against precipitated proteins was assessed with sera of 98 patients (neuromyotonia 46, myasthenia gravis 52, thymoma 42; 33 of them with overlapping syndromes) and 219 controls (other neurologic diseases, cancer, and healthy volunteers). RESULTS: Immunoprecipitation studies identified 3 targets, including the Netrin-1 receptors DCC (deleted in colorectal carcinoma) and UNC5A (uncoordinated-5A) as well as Caspr2 (contactin-associated protein-like 2). Cell-based assays with these antigens showed that among the indicated patients, 9 had antibodies against Netrin-1 receptors (7 with additional Caspr2 antibodies) and 5 had isolated Caspr2 antibodies. Only one of the 219 controls had isolated Caspr2 antibodies with relapsing myelitis episodes. Among patients with neuromyotonia and/or myasthenia gravis, the presence of Netrin-1 receptor or Caspr2 antibodies predicted thymoma (p < 0.05). Coexisting Caspr2 and Netrin-1 receptor antibodies were associated with concurrent thymoma, myasthenia gravis, and neuromyotonia, often with Morvan syndrome (p = 0.009). Expression of DCC, UNC5A, and Caspr2 proteins was demonstrated in paraffin-embedded thymoma samples (3) and normal thymus. CONCLUSIONS: Antibodies against Netrin-1 receptors (DCC and UNC5a) and Caspr2 often coexist and associate with thymoma in patients with neuromyotonia and myasthenia gravis. CLASSIFICATION OF EVIDENCE: This study provides Class III evidence that antibodies against Netrin-1 receptors can identify patients with thymoma (sensitivity 21.4%, specificity 100%).