ROS1-rearranged lung cancer: a clinicopathologic and molecular study of 15 surgical cases

Cytologic Diagnoses of Lung Adenocarcinoma With Concomitant Metastasis From a Different Primary: A Case Series

Lung adenocarcinoma is a common malignancy that can metastasize. The lung is also a common site for metastasis from other sites. Prompt and accurate diagnosis is critical for patient management. The diagnosis of lung adenocarcinoma can be occasionally challenging due to overlapping clinical and pathological features with adenocarcinomas from other origins. We present three cases of lung adenocarcinomas with concomitant metastatic adenocarcinomas of different primaries in the same endobronchial ultrasound-guided fine-needle aspiration (EBUS-FNA) or core biopsy procedures. The first case showed metastatic ROS-rearranged lung adenocarcinoma and metastatic ampullary adenocarcinoma involving different mediastinal lymph nodes, respectively, in a patient with no previous history of malignancy. The second case showed metastatic lung adenocarcinoma with MET exon 14 deletion and metastatic breast adenocarcinoma involving different mediastinal lymph nodes, respectively, in a patient with a previous history of breast carcinoma. The third case showed metastatic prostatic adenocarcinoma to a pre-existing lung mucinous adenocarcinoma in a patient with a previous history of prostatic adenocarcinoma. Our report highlights attention to details, judicious use of immunostains, and ancillary molecular studies in complex pathology cases. Cytohistological findings are also correlated with molecular test results.

Lung Adenocarcinoma Exhibiting Thanatosomes (Hyaline Bodies), Cytoplasmic Clearing, and Nuclear Pleomorphism, with a KRAS Mutation

Since epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors were introduced in 2004, various driver gene mutations have been identified in non-small cell lung cancer, particularly adenocarcinoma, where mutations are typically mutually exclusive. EGFR and Kirsten rat sarcoma viral oncogene (KRAS) mutations are most prevalent in Japan, with routine testing now standard. However, hematoxylin and eosin staining often fails to detect mutations, except in cases such as ALK fusion lung cancer. We report a 76-year-old non-smoking Japanese woman diagnosed with adenocarcinoma confirmed as KRAS G12D/S-positive. Histological features, including thanatosomes (hyaline globules), nuclear pleomorphism, and cytoplasmic clearing, may aid in identifying mutations. Numerous thanatosomes were identified, some containing nuclear dust. Thanatosomes revealed periodic acid-Schiff reactivity with diastase resistance, fuchsinophilia with Masson's trichrome stain, and dark blue-black color with Mallory's PTAH stain. This is the first report linking thanatosomes in KRAS-mutant pulmonary adenocarcinoma to apoptosis via cleaved caspase-3 staining.

Targeting ROS1 rearrangements in non-small cell lung cancer: Current insights and future directions

ROS1 rearrangements define a molecular subset of non-small cell lung cancer (NSCLC) by accounting for 1%-2% of cases. Targeted therapy with ROS1 tyrosine kinase inhibitors (TKIs) has significantly improved the outcomes for these patients. First-generation inhibitors, such as crizotinib and entrectinib, have demonstrated impressive efficacy, with objective response rates exceeding 60%-70%. However, the emergence of resistance mechanisms, including solvent-front mutations such as ROS1 G2032R, and limited blood-brain barrier penetration have limited the long-term efficacy of early-generation agents. Next-generation TKIs, including lorlatinib, taletrectinib, and repotrectinib, have been developed to overcome these challenges. These agents show enhanced central nervous system (CNS) penetration and activity against on-target ROS1 resistance mutations. Repotrectinib, a potent, CNS-penetrant ROS1 inhibitor, has demonstrated superior activity in both TKI-naive and -resistant tumors, including those harboring the G2032R mutation. Zidesamtinib, a highly selective next-generation ROS1 inhibitor, further addresses TRK-mediated off-target neurological toxicities seen with prior agents, and is poised to offer improved tolerability. Ongoing research is focused on optimizing sequencing strategies for ROS1 inhibitors and exploring combination approaches to prevent or overcome resistance. In addition, the development of novel diagnostic tools, including RNA-based next-generation sequencing, has enhanced the detection of functional ROS1 fusions by ensuring that patients with actionable mutations receive appropriate targeted therapies. These advances highlight the evolving landscape of treatment for ROS1-positive NSCLC, with the aim of maximizing long-term survival and quality of life.

ROS1-rearranged non-small cell lung cancer: Understanding biology and optimizing management in the era of new approvals

Rearrangements involving the ROS1 gene are infrequent in non-small cell lung cancer (NSCLC) but represent an important targetable driver alteration. Occurring most commonly in patients with adenocarcinoma who have a light or never smoking history, ROS1 rearrangements can be identified by either fluorescence in-situ hybridization (FISH) or next-generation sequencing techniques. Multiple tyrosine kinase inhibitors (TKIs) are now available for the effective treatment of ROS1-rearranged NSCLC in the metastatic setting including crizotinib, entrectinib, and repotrectinib as first-line therapy options. In addition, newer targeted therapies with increased selectivity for ROS1 over other targets are also emerging. As treatment of the disease continues to evolve, understanding the clinical course of patients with ROS1-rearranged NSCLC as well as the data supporting the latest therapy options is key to timely, effective, and longitudinal care.

ROS1 kinase inhibition reimagined: identifying repurposed drug via virtual screening and molecular dynamics simulations for cancer therapeutics

Precision medicine has revolutionized modern cancer therapeutic management by targeting specific molecular aberrations responsible for the onset and progression of tumorigenesis. ROS proto-oncogene 1 (ROS1) is a receptor tyrosine kinase (RTK) that can induce tumorigenesis through various signaling pathways, such as cell proliferation, survival, migration, and metastasis. It has emerged as a promising therapeutic target in various cancer types. However, there is very limited availability of specific ROS1 inhibitors for therapeutic purposes. Exploring repurposed drugs for rapid and effective treatment is a useful approach. In this study, we utilized an integrated approach of virtual screening and molecular dynamics (MD) simulations of repurposing existing drugs for ROS1 kinase inhibition. Using a curated library of 3648 FDA-approved drugs, virtual screening identified drugs capable of binding to ROS1 kinase domain. The results unveil two hits, Midostaurin and Alectinib with favorable binding profiles and stable interactions with the active site residues of ROS1. These hits were subjected to stability assessment through all-atom MD simulations for 200 ns. MD results showed that Midostaurin and Alectinib were stable with ROS1. Taken together, the study showed a rational framework for the selection of repurposed Midostaurin and Alectinib with ROS1 inhibitory potential for therapeutic management after further validation.

Concomitant epidermal growth factor receptor mutation/c-ros oncogene 1 rearrangement in non-small cell lung cancer: A case report

BACKGROUND

Epidermal growth factor receptor (EGFR) mutation and c-ros oncogene 1 (ROS1) rearrangement are key genetic alterations and predictive tumor markers for non-small cell lung cancer (NSCLC) and are typically considered to be mutually exclusive. EGFR/ROS1 co-mutation is a rare event, and the standard treatment approach for such cases is still equivocal.

CASE SUMMARY

Herein, we report the case of a 64-year-old woman diagnosed with lung adenocarcinoma, with concomitant EGFR L858R mutation and ROS1 rearrangement. The patient received two cycles of chemotherapy after surgery, but the disease progressed. Following 1-month treatment with gefitinib, the disease progressed again. However, after switching to crizotinib, the lesion became stable. Currently, crizotinib has been administered for over 53 months with a remarkable treatment effect.

CONCLUSION

The efficacy of EGFR tyrosine kinase inhibitors and crizotinib was vastly different in this NSCLC patient with EGFR/ROS1 co-mutation. This report will aid future treatment of such patients.

Transforming tumoroids derived from ALK-positive pulmonary adenocarcinoma to squamous cell carcinoma in vivo

Approximately 3-5% of non-small cell lung cancers (NSCLC) harbor ALK fusion genes and may be responsive to anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitors. There are only a few reports on cell lines with EML4-ALK variant 3 (v3) and tumoroids that can be subject to long-term culture (> 3 months). In this study, we established tumoroids (PDT-LUAD#119) from a patient with lung cancer harboring EML4-ALK that could be cultured for 12 months. Whole-exome sequencing and RNA sequencing analyses revealed TP53 mutations and an EML4-ALK v3 mutation. PDT-LUAD#119 lung tumoroids were sensitive to the ALK tyrosine kinase inhibitors (ALK TKIs) crizotinib, alectinib, entrectinib, and lorlatinib, similar to NCI-H3122 cells harboring EML4-ALK variant 1 (v1). Unexpectedly, clear squamous cell carcinoma and solid adenocarcinoma were observed in xenografts from PDT-LUAD#119 lung tumoroids, indicating adenosquamous carcinoma. Immunostaining revealed that the squamous cell carcinoma was ALK positive, suggesting a squamous transformation of the adenocarcinoma. Besides providing a novel cancer model to support basic research on ALK-positive lung cancer, PDT-LUAD#119 lung tumoroids will help elucidate the pathogenesis of adenosquamous carcinoma.

Different effects of crizotinib treatment in two non-small cell lung cancer patients with SDC4::ROS1 fusion variants

The possibility of stratifying patients according to differences in ROS proto-oncogene 1 (ROS1) fusion partners has been discussed. This study aimed to clarify the clinicopathological differences between two SDC4::ROS1 positive NSCLC cases who had different responses to crizotinib. Cytology and pathology samples from two NSCLC cases with SDC4::ROS1 who were diagnosed and treated with crizotinib at Nihon University Itabashi Hospital were obtained. Case 1 has been well-controlled with crizotinib for over 5 years, but case 2 was worse and overall survival was 19 months. Sequencing analysis of ROS1 fusion genes was performed by reverse-transcription-PCR and Sanger's sequencing methods. In addition, thyroid transcription factor (TTF)-1, ROS-1, Ki67, and phosphorylated extracellular signal-regulated kinase (pERK)1/2 expression were investigated using immunohistochemistry. Sequencing analysis showed SDC4 exon2::ROS1 exon 32 (exon33 deleted) in case 1, and coexistence of SDC4 exon2::ROS1 exon 34 and SDC4 exon2::ROS1 exon35 in case 2. The Ki67 index was not different, but ROS1 and pERK1/2 expression levels tended to be higher in the tumor cells of case 2 than in case 1. Therapeutic response to crizotinib and patients' prognosis in ROS1 rearranged NSCLC may be related to the activation of ROS1 signaling, depending on ROS1 and pERK1/2 overexpression status, even if the ROS1 fusion partner is the same.

Molecular pathology of non-small cell carcinoma

Currently, lung cancer is treated by the highest number of therapeutic options and the benefits are based on multiple large-scale sequencing studies, translational research and new drug development, which has promoted our understanding of the molecular pathology of lung cancer. According to the driver alterations, different characteristics have been revealed, such as differences in ethnic prevalence, median age and alteration patterns. Consequently, beyond traditional chemoradiotherapy, molecular-targeted therapy and treatment with immune check-point inhibitors (ICI) also became available major therapeutic options. Interestingly, clinical results suggest that the recently established therapies target distinct lung cancer proportions, particularly between the EGFR/ALK and PD-1/PD-L1-positive subsets, e.g. the kinase inhibitors target driver mutation-positive tumours, whereas driver mutation-negative tumours respond to ICI treatment. These therapeutic efficacy-related differences might be explained by the molecular pathogenesis of lung cancer. Addictive driver mutations promote tumour formation with powerful transformation performance, resulting in a low tumour mutation burden, reduced immune surveillance, and subsequent poor response to ICIs. In contrast, regular tobacco smoke exposure repeatedly injures the proximal airway epithelium, leading to accumulated genetic alterations. In the latter pathway, overgrowth due to alteration and immunological exclusion against neoantigens is initially balanced. However, tumours could be generated from certain clones that outcompete immunological exclusion and outgrow the others. Consequently, this cancer type responds to immune check-point treatment. These pathogenic differences are explained well by the two-compartment model, focusing upon the anatomical and functional composition of distinct cellular components between the terminal respiratory unit and the air-conducting system.

Clinicopathological features and prognostic significance of pulmonary adenocarcinoma with signet ring cell components: meta-analysis and SEER analysis

Pulmonary adenocarcinoma is a common type of lung cancer that has been on the rise in recent years. Signet ring cell components (SRCC) can be present in various patterns of pulmonary adenocarcinoma, including papillary, acinar, and solid patterns. "Signet ring cell carcinoma" is a distinct subtype in the 2014 WHO classification of lung neoplasms, subsequent WHO classifications in 2015 and 2021 have deemed signet ring cells as accompanying morphological features with no clinical significance. The prognostic and clinical implications of SRCC in pulmonary adenocarcinoma remain controversial. Therefore, we conducted a meta-analysis to investigate the clinicopathological features and prognostic factors of SRCC in pulmonary adenocarcinoma. We conducted a comprehensive search in PubMed, EMBASE, and Web of Science to identify studies that examined the clinicopathological features and prognostic implications of pulmonary adenocarcinoma with SRCC. We used both fixed- and random-effects models to analyze the data and calculate the pooled hazard ratio (HR) and odds ratio (OR) with 95% confidence intervals (CIs). Additionally, we explored the prognostic significance of SRCC in pulmonary adenocarcinoma using the Surveillance, Epidemiology, and End Results (SEER) database. Our meta-analysis included 29 studies with pulmonary adenocarcinoma and SRCC components. The results showed that pulmonary adenocarcinoma with SRCC was associated with larger tumor size (OR = 1.99; 95% CI, 1.62-2.44, p < 0.001), advanced overall stage (OR = 5.18, 95% CI, 3.28-8.17, p < 0.00001) and lymph node stage (OR = 5.79, 95% CI, 1.96-17.09, p = 0.001), and worse overall survival (OS) compared to those without SRCC (HR = 1.80, 95% CI, 1.50-2.16, p < 0.00001). Analysis using the SEER dataset confirmed these findings. Our meta-analysis provides evidence that pulmonary adenocarcinoma with SRCC is associated with distinct clinicopathological features and a poorer prognosis. These findings have important implications for the management and treatment of patients. However, further studies are needed to validate these findings and explore the significance of SRCC in various subtypes of pulmonary adenocarcinoma.

Analysis of CD74 Occurrence in Oncogenic Fusion Proteins

CD74 is a type II cell surface receptor found to be highly expressed in several hematological and solid cancers, due to its ability to activate pathways associated with tumor cell survival and proliferation. Over the past 16 years, CD74 has emerged as a commonly detected fusion partner in multiple oncogenic fusion proteins. Studies have found CD74 fusion proteins in a range of cancers, including lung adenocarcinoma, inflammatory breast cancer, and pediatric acute lymphoblastic leukemia. To date, there are five known CD74 fusion proteins, CD74-ROS1, CD74-NTRK1, CD74-NRG1, CD74-NRG2α, and CD74-PDGFRB, with a total of 16 different variants, each with unique genetic signatures. Importantly, the occurrence of CD74 in the formation of fusion proteins has not been well explored despite the fact that ROS1 and NRG1 families utilize CD74 as the primary partner for the formation of oncogenic fusions. Fusion proteins known to be oncogenic drivers, including those of CD74, are typically detected and targeted after standard chemotherapeutic plans fail and the disease relapses. The analysis reported herein provides insights into the early intervention of CD74 fusions and highlights the need for improved routine assessment methods so that targeted therapies can be applied while they are most effective.

Clinical Relevance of Targeted Therapy and Immune-Checkpoint Inhibition in Lung Cancer

Lung cancer (LC) represents the second most diagnosed tumor and the malignancy with the highest mortality rate. In recent years, tremendous progress has been made in the treatment of this tumor thanks to the discovery, testing, and clinical approval of novel therapeutic approaches. Firstly, targeted therapies aimed at inhibiting specific mutated tyrosine kinases or downstream factors were approved in clinical practice. Secondly, immunotherapy inducing the reactivation of the immune system to efficiently eliminate LC cells has been approved. This review describes in depth both current and ongoing clinical studies, which allowed the approval of targeted therapies and immune-checkpoint inhibitors as standard of care for LC. Moreover, the present advantages and pitfalls of new therapeutic approaches will be discussed. Finally, the acquired importance of human microbiota as a novel source of LC biomarkers, as well as therapeutic targets to improve the efficacy of available therapies, was analyzed. Therapy against LC is increasingly becoming holistic, taking into consideration not only the genetic landscape of the tumor, but also the immune background and other individual variables, such as patient-specific gut microbial composition. On these bases, in the future, the research milestones reached will allow clinicians to treat LC patients with tailored approaches.

Lung cancer presenting with central nervous system metastasis: Clinicopathological and molecular analysis of 171 cases

A subset of lung carcinoma presents initially with brain metastasis. Precise subtyping is mandatory for optimized treatment of these advanced aggressive carcinomas. We herein analyzed surgical biopsies from 171 Patients (99 males and 72 females aged 48-96; mean, 72), who presented with brain metastasis of lung cancer. In addition to conventional subtyping, we applied an extended immunohistochemistry (IHC) panel and performed several molecular tests looking for potential therapeutic targets other than EGFR mutations. Non-small cell carcinoma (NSCLC) comprised 157 (91.8 %) of cases: 109 (63.7 %) adenocarcinomas, 27 (15.8 %) squamous cell (SCC), 18 (10.5 %) large cell undifferentiated, 1 (0.6 %) adenosquamous and 2 (1.2 %) unclassified carcinomas. Of the adenocarcinomas, 81.7 % were TTF1+. Notably, 45 % of those TTF1-negative cases expressed HepPar1. SMARCA4 and SMARCA2 loss was observed in 13/171 (7.6 %) and 32/163 (19.6 %) cases, respectively; mainly TTF1- (40.0 %) and HepPar1+ (38.1 %) adenocarcinomas were affected by SMARCA2/4 loss. Loss of at least one mismatch repair (MMR) protein was observed in 3/156 (1.9 %) cases (2 adenocarcinomas and 1 large cell neuroendocrine carcinoma/LCNEC). Limited available data on mutation testing showed a frequency of EGFR mutations of 4.3% and of KRAS mutations of 57%. HER2 expression (2+/3+) was found in 45/166 (27.1 %) of cases with amplification verified by CISH in 18/38 (47.4 % of immunopositive cases and 10.5 % of the whole cohort); all but one were adenocarcinomas. Other genetic abnormalities detected included EML4::ALK rearrangements in 3 (1.8 %; 2 TTF1+ adenocarcinomas and 1 LCNEC) and RET rearrangements in one SCNEC. Variable subsets of tumors revealed amplifications of several potentially therapeutically targetable genes including MYC (30.0 %), MET (10.1 %), HER2 (10 %), FGFR1 (9.6 %), FGFR3 (4.6 %), and FGFR2 (3.4 %). This study highlights a highly heterogeneous molecular background in lung cancer presenting with CNS metastases. These findings highlight the need for individualized tumor testing strategies looking for potential therapeutic targets for this aggressive disease.

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

INTRODUCTION

An accurate histological evaluation of invasive lung adenocarcinoma is essential for a correct clinical and pathological definition of the tumour. Different grading systems have been proposed to predict the prognosis of invasive lung adenocarcinoma.

AREAS COVERED

Invasive non mucinous lung adenocarcinoma is often morphologically heterogeneous, consisting of complex combinations of architectural patterns with different proportions. Several grading systems for non-mucinous lung adenocarcinoma have been proposed, being the main based on architectural differentiation and the predominant growth pattern. Herein we perform a thorough review of the literature using PubMed, Scopus and Web of Science and we highlight the peculiarities and the differences between the main grading systems and compare the data about their prognostic value. In addition, we carried out an evaluation of the proposed grading systems for less common histological variants of lung adenocarcinoma, such as fetal adenocarcinoma and invasive mucinous adenocarcinoma.

EXPERT OPINION

The current IASLC grading system, based on the combined score of predominant growth pattern plus high-grade histological pattern, shows the stronger prognostic significance than the previous grading systems in invasive non mucinous lung adenocarcinoma.

Concurrent classic driver oncogenes mutation with ROS1 rearrangement predicts superior clinical outcome in NSCLC patients

BACKGROUND

There is high mortality rate and poor prognosis in lung cancer, especially non-small-cell lung cancer (NSCLC). Recent study showed that concurrent classic driver oncogene mutation with ROS1 rearrangement was found in NSCLC patients. However, whether this would affect the development and prognosis of NSCLC is still unclear.

OBJECTIVE

To explore the clinical characteristics and prognosis of NSCLC patients harboring concurrent classic driver oncogene mutation with ROS1 rearrangement.

METHODS

A retrospective study was conducted on 220 patients diagnosed with NSCLC. All samples were screened for EGFR and KRAS using amplification-refractory mutation system assay, and for ALK, ROS1 using RT-PCR. The clinical characteristics and clinical outcomes of concurrent gene alterations with ROS1 rearrangement were analyzed.

RESULTS

In 220 patients, 12 (5.45%) were ROS1 rearrangement, who tend to be younger, non-smokers. The mutation rates of EGFR, KRAS, ALK and ROS1 in NSCLC were 28.64%, 1.82%, 3.64% and 5.45%, respectively. ROS1 rearrangement was identified to co-occur in 5 (2.27%) NSCLC patients. ROS1/EGFR co-alterations were found in 3.17% of NSCLC patients, 16.67% of ROS1-positive NSCLC patients. Concomitant ROS1/ALK rearrangement constituted 37.50% in ALK-positive patients, and 25.00% in ROS1-positive patients. SDC4-ROS1 was the most common fusion partner in concurrent ROS1 rearrangement patients. The median overall survival of NSCLC with concurrent ROS1 rearrangement group and single ROS1 rearrangement group were 25 months and 14 months.

CONCLUSION

Concurrent driver oncogenes mutation with ROS1 rearrangement defines a unique subgroup of NSCLC. Patients with concomitant ROS1 rearrangement might have a better prognosis.

The Role of Genomics and Proteomics in Lung Cancer Early Detection and Treatment

Lung cancer is the leading cause of cancer-related death worldwide, with non-small-cell lung cancer (NSCLC) being the primary type. Unfortunately, it is often diagnosed at advanced stages, when therapy leaves patients with a dismal prognosis. Despite the advances in genomics and proteomics in the past decade, leading to progress in developing tools for early diagnosis, targeted therapies have shown promising results; however, the 5-year survival of NSCLC patients is only about 15%. Low-dose computed tomography or chest X-ray are the main types of screening tools. Lung cancer patients without specific, actionable mutations are currently treated with conventional therapies, such as platinum-based chemotherapy; however, resistances and relapses often occur in these patients. More noninvasive, inexpensive, and safer diagnostic methods based on novel biomarkers for NSCLC are of paramount importance. In the current review, we summarize genomic and proteomic biomarkers utilized for the early detection and treatment of NSCLC. We further discuss future opportunities to improve biomarkers for early detection and the effective treatment of NSCLC.

Multiplex fluorescence in situ hybridization testing for anaplastic lymphoma kinase and c-ros oncogene 1 gene rearrangements on cytology smears in lung adenocarcinomas: comparative study with formalin-fixed paraffin-embedded sections

INTRODUCTION

Multiplex anaplastic lymphoma kinase (ALK)/c-ros oncogene 1 (ROS1) fluorescence in situ hybridization (FISH) probes conserve tissue by analyzing both ALK and ROS1 gene rearrangements (ALK-R/ROS1-R) in a single test. The positivity cutoffs have been validated on formalin-fixed, paraffin-embedded (FFPE) tissue sections and not tested on non-cell block (CB) cytology preparations. We sought to validate non-CB cytology preparations for the detection of ALK-R/ROS1-R using multiplex ALK/ROS1 FISH probes by comparing the results with matched FFPE results.

MATERIALS AND METHODS

During the 3.5-year study period, FISH using the FlexISH ALK/ROS1 DistinguISH Probe (ZytoVision) was performed in non-CB cytology preparations of patients for whom FISH on FFPE sections was performed.

RESULTS

A total of 20 patients had one or more non-CB cytology preparations (n = 27) suitable for FISH analysis. These comprised direct smears (n = 17), smears from centrifuged effusion pellets (n = 8), cytospin smears (n = 1), and biopsy imprint smears (n = 1). These had been fixed in 95% ethanol (n = 18) or air dried (n = 9), and stained with Papanicolaou (n = 14), May-Grünwald-Giemsa (n = 9), immunocytochemistry (n = 3), or hematoxylin and eosin (n = 1). The median archival time was 1 year. Successful FISH results were achieved in 14 samples (6 with ALK-R, 2 with ROS1-R, 6 negative) and were concordant with the FFPE FISH results for 13 of 14 cases. The single case with discordant results between cytology and FFPE FISH showed ALK-R on cytology concordant with positive ALK D5F3 companion diagnostics assay results and was considered a false-negative FFPE FISH result. FISH failure occurred mainly in the older archived slides because of overdigestion (n = 5), hybridization failure (n = 5), or excessive background fluorescence (n = 3).

CONCLUSIONS

Non-CB cytology smears are highly suitable for multiplex FISH analysis with 100% concordance with FFPE FISH and/or ALK D5F3 companion diagnostics assay results.

ROS-1 Fusions in Non-Small-Cell Lung Cancer: Evidence to Date

The ROS-1 gene plays a major role in the oncogenesis of numerous tumors. ROS-1 rearrangement is found in 0.9–2.6% of non-small-cell lung cancers (NSCLCs), mostly lung adenocarcinomas, with a significantly higher rate of women, non-smokers, and a tendency to a younger age. It has been demonstrated that ROS-1 is a true oncogenic driver, and tyrosine kinase inhibitors (TKIs) targeting ROS-1 can block tumor growth and provide clinical benefit for the patient. Since 2016, crizotinib has been the first-line reference therapy, with two-thirds of the patients’ tumors responding and progression-free survival lasting ~20 months. More recently developed are ROS-1-targeting TKIs that are active against resistance mechanisms appearing under crizotinib and have better brain penetration. This review summarizes current knowledge on ROS-1 rearrangement in NSCLCs, including the mechanisms responsible for ROS-1 oncogenicity, epidemiology of ROS-1-positive tumors, methods for detecting rearrangement, phenotypic, histological, and molecular characteristics, and their therapeutic management. Much of this work is devoted to resistance mechanisms and the development of promising new molecules.

Deepening the Knowledge of ROS1 Rearrangements in Non-Small Cell Lung Cancer: Diagnosis, Treatment, Resistance and Concomitant Alterations

ROS proto-oncogene 1 (ROS1) rearrangements are reported in about 1-2% of non-squamous non-small-cell lung cancer (NSCLC). After efficacy of crizotinib was demonstrated, identification of ROS1 translocations in advanced disease became fundamental to give patients the chance of specific and effective treatment. Different methods are available for detection of rearrangements, and probably the real prevalence of ROS1 rearrangements is higher than that reported in literature, as our capacity to detect gene rearrangements is improving. In particular, with next generation sequencing (NGS) techniques, we are currently able to assess multiple genes simultaneously with increasing sensitivity. This is leading to overcome the "single oncogenic driver" paradigm, and in the very near future, the co-existence of multiple drivers will probably emerge more frequently and represent a therapeutic issue. Since recently, crizotinib has been the only available therapy, but today, many other tyrosine kinase inhibitors (TKI) are emerging and seem promising both in first and subsequent lines of treatment. Indeed, novel inhibitors are also able to overcome resistance mutations to crizotinib, hypothesizing a possible sequential strategy also in ROS1-rearranged disease. In this review, we will focus on ROS1 rearrangements, dealing with diagnostic aspects, new therapeutic options, resistance issues and the coexistence of ROS1 translocations with other molecular alterations.

Re-Expression of Poly/Oligo-Sialylated Adhesion Molecules on the Surface of Tumor Cells Disrupts Their Interaction with Immune-Effector Cells and Contributes to Pathophysiological Immune Escape

Glycans linked to surface proteins are the most complex biological macromolecules that play an active role in various cellular mechanisms. This diversity is the basis of cell-cell interaction and communication, cell growth, cell migration, as well as co-stimulatory or inhibitory signaling. Our review describes the importance of neuraminic acid and its derivatives as recognition elements, which are located at the outermost positions of carbohydrate chains linked to specific glycoproteins or glycolipids. Tumor cells, especially from solid tumors, mask themselves by re-expression of hypersialylated neural cell adhesion molecule (NCAM), neuropilin-2 (NRP-2), or synaptic cell adhesion molecule 1 (SynCAM 1) in order to protect themselves against the cytotoxic attack of the also highly sialylated immune effector cells. More particularly, we focus on α-2,8-linked polysialic acid chains, which characterize carrier glycoproteins such as NCAM, NRP-2, or SynCam-1. This characteristic property correlates with an aggressive clinical phenotype and endows them with multiple roles in biological processes that underlie all steps of cancer progression, including regulation of cell-cell and/or cell-extracellular matrix interactions, as well as increased proliferation, migration, reduced apoptosis rate of tumor cells, angiogenesis, and metastasis. Specifically, re-expression of poly/oligo-sialylated adhesion molecules on the surface of tumor cells disrupts their interaction with immune-effector cells and contributes to pathophysiological immune escape. Further, sialylated glycoproteins induce immunoregulatory cytokines and growth factors through interactions with sialic acid-binding immunoglobulin-like lectins. We describe the processes, which modulate the interaction between sialylated carrier glycoproteins and their ligands, and illustrate that sialic acids could be targets of novel therapeutic strategies for treatment of cancer and immune diseases.

Relationship between clinical features and gene mutations in non-small cell lung cancer with osteoblastic bone metastasis

OBJECTIVE

Lung cancer patients presenting with osteoblastic bone metastases at the first visit is rare. We investigated the clinical characteristics and gene mutation rate of non-small cell lung cancer patients with osteoblastic bone metastases at the time of the initial diagnosis.

MATERIALS AND METHODS

We retrospectively screened newly diagnosed non-small cell lung cancer patients with osteoblastic bone metastases who presented from June 2015 to March 2021, and analyzed their clinical characteristics and status of EGFR gene mutations, EML4-ALK translocation and ROS1 rearrangements. For comparison, we collected data from patients with non-small cell lung cancer who had osteolytic bone metastases at their first visit between June 2015 and March 2021.

RESULTS

Fifty patients had bone metastases at the initial diagnosis. Among them, eight patients (8/50 = 16%) had osteoblastic bone metastases, and the lung tumors in all of them were histopathologically adenocarcinomas. Among the eight cases, two were EGFR mutation-positive, none were EML4-ALK translocation-positive, two were ROS1 rearrangement-positive, and the remaining four cases were negative for all three gene mutations/rearrangements. Compared with the osteolytic bone metastasis group, the percentage of non-smokers was higher (p = 0.020) and the ROS1 rearrangement positivity rate was higher (p = 0.05) in the osteoblastic bone metastasis group.

CONCLUSION

Our results indicate that osteoblastic bone metastases in NSCLC are suggestive of adenocarcinoma, and that a high proportion of these patients might be positive for ROS1 rearrangements, and hence, indicated for more aggressive diagnostic biopsies.

A novel CD74-ROS1 gene fusion in a patient with inflammatory breast cancer: a case report

BACKGROUND

CD74-ROS1 fusion genes have been detected in non-small cell lung carcinomas (NSCLC), but not in inflammatory breast cancer.

CASE PRESENTATION

Herein, we report a CD74-ROS1 fusion gene identified in a 64-year-old Chinese woman with inflammatory breast cancer (IBC). The patient initially presented with a rapidly growing mass in the left breast with diffuse erythema developing over a period of 2 months. Diagnosis of invasive breast carcinoma was made by core needle biopsy. Positron emission tomography-computed tomography (PET/CT) demonstrated multiple organ metastases. Genomic DNA was extracted from tumor tissue and analyzed using next-generation sequencing (NGS). The CD74-ROS1 fusion gene was detected in the genomic DNA. The patient refused crizotinib treatment, and could not tolerate the side effects of palliative chemotherapy. Unfortunately, the patient died 4 months after diagnosis.

CONCLUSION

We report the case of a CD74-ROS1 fusion gene in a patient with IBC. This may reveal, for the first time, a possible association between CD74-ROS1 gene fusion and rapid progression of inflammatory breast cancer. Multigene panel testing can be performed when rapidly progressive breast cancer occurs and could reveal potential therapeutic strategies.

Different clinical features between patients with ROS1-positive and ALK-positive advanced non-small cell lung cancer

Objective

To compare the baseline clinical characteristics between patients with ROS1-positive and ALK-positive advanced non-small cell lung cancer (NSCLC), and the correlations of these subtypes with the distribution of metastases.

Methods

We compared the clinical characteristics and imaging features of patients with ROS1-positive and ALK-positive NSCLC using statistical methods.

Results

Data for 232 patients were analyzed. Compared with ALK-positive NSCLC, ROS1-positive NSCLC was more likely to occur in women (71% vs 53%), and primary lesions ≤3 cm were more common in patients with ROS1-positive compared with ALK-positive NSCLC (58% vs 37%). There was no significant difference in the distribution of metastases between the two groups. Subgroup analysis within the ROS1-positive group showed that, compared with primary lesions >3 cm, primary lesions ≤3 cm were more likely to present as peripheral tumors (72% vs 43%) and more likely to exhibit non-solid density (44% vs 4%).

Conclusions

Although ROS1-positive and ALK-positive NSCLCs show similar clinical features, the differences may help clinicians to identify patients requiring further genotyping at initial diagnosis.

Screening for ROS1 fusions in patients with advanced non-small cell lung carcinomas using the VENTANA ROS1 (SP384) Rabbit Monoclonal Primary Antibody

Introduction: The development of several ROS1 inhibitors means that the importance of accurately identifying ROS1-positive lung cancer patients has never been greater. Therefore, it is crucial that ROS1 testing assays become more standardized.Areas covered: Based on primary literature, combined with personal diagnostic and research experience, this review provide a pragmatic update on the use of the recently released VENTANA ROS1 (SP384) Rabbit Monoclonal Primary Antibody.Expert opinion: This assay provides high sensitivity, so it is an excellent analytical option when screening for ROS1 fusions in patients with advanced non-small cell lung carcinomas.

Interstitial Deletions Generating Fusion Genes

A fusion gene is the physical juxtaposition of two different genes resulting in a structure consisting of the head of one gene and the tail of the other. Gene fusion is often a primary neoplasia-inducing event in leukemias, lymphomas, solid malignancies as well as benign tumors. Knowledge about fusion genes is crucial not only for our understanding of tumorigenesis, but also for the diagnosis, prognostication, and treatment of cancer. Balanced chromosomal rearrangements, in particular translocations and inversions, are the most frequent genetic events leading to the generation of fusion genes. In the present review, we summarize the existing knowledge on chromosome deletions as a mechanism for fusion gene formation. Such deletions are mostly submicroscopic and, hence, not detected by cytogenetic analyses but by array comparative genome hybridization (aCGH) and/or high throughput sequencing (HTS). They are found across the genome in a variety of neoplasias. As tumors are increasingly analyzed using aCGH and HTS, it is likely that more interstitial deletions giving rise to fusion genes will be found, significantly impacting our understanding and treatment of cancer.

Histological characteristics of lung adenocarcinoma with uncommon actionable alterations: special emphasis on MET exon 14 skipping alterations

AIMS

In the evolving era of precision medicine, increasing emphasis is placed on detecting molecular alterations driving the development of specific cancers and targeting them with matched therapies that can yield the best outcomes for patients. Lung adenocarcinomas with uncommon actionable alterations, including MET exon 14 skipping (METex14), ERBB2 and BRAF mutations, are rare and poorly characterised cancers.

METHODS AND RESULTS

To more clearly understand the histopathological features of lung adenocarcinoma with uncommon actionable alterations, we compared the histological features of 678 cases with mitogenic driver alterations from 996 surgically resected lung adenocarcinomas. Genomic data from our cohort revealed METex14, ERBB2 and BRAF mutations in 13, 16 and 15 cases, respectively. Patients who had lung adenocarcinoma with METex14 were often elderly females. Histological features such as clear cell features (23%), hyaline globules (31%) and nuclear pleomorphism (39%) were the most frequently identified in METex14-positive cases; among those, three cases (23%) had tumour cells with bizarre giant or multilobulated nuclei. Additionally, the micropapillary pattern was the most frequently identified in ERBB2-mutated lung adenocarcinoma (31%). Lung adenocarcinoma with BRAF mutations tended to be less invasive, and the BRAF V600E mutation was identified in only one case with lepidic adenocarcinoma. Immunohistochemically, all METex14, ERBB2 and BRAF-positive tumours, except for invasive mucinous adenocarcinoma, were positive for thyroid transcription factor 1 (TTF-1).

CONCLUSIONS

Our data from Japanese patients showed that lung adenocarcinoma with METex14 had unique clinicopathological characteristics: tumour cells with marked nuclear pleomorphism, hyaline globules and expression of TTF-1 in elderly women who never or lightly smoked.

Profile of entrectinib in the treatment of ROS1-positive non-small cell lung cancer: Evidence to date

ROS proto-oncogene 1 (ROS1) encodes a type I integral membrane protein with tyrosine kinase activity and whose activating alterations are involved in the aggressiveness of several tumor types. Fusions involving ROS1 gene are present in 1-2% of lung adenocarcinomas and other solid tumors. Entrectinib, also known as RXDX-101, is a potent second-generation, multitarget oral inhibitor against NTRK1, NTRK2, NTRK3, ALK, and ROS1 with the ability to cross the blood-brain barrier. Results of Phase I and II trials have led the Food and Drug Administration to grant approval to entrectinib for the treatment of patients with metastatic, ROS1-positive non-small cell lung cancer (NSCLC). In this review, we will describe the biology of ROS1, as well as results of the efficacy and safety of different clinical trials evaluating entrectinib in ROS1-positive NSCLC.

FISH patterns of ROS1, MET, and ALK with a correlation of ALK immunohistochemistry in lung cancer: a case for introducing ALK immunohistochemistry 'Equivocal' interpretation category in the Ventana anti-ALK (D5F3) CDx assay - A tertiary cancer center experience

Background

Mutations in ROS1, ALK, and MET genes are targetable alterations in non-small cell lung cancer (NSCLC). They can be evaluated by different techniques, most commonly fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC).

Methods

We explored the prevalence of ROS1, ALK, MET mutations, discuss clinicopathological associations and FISH signal patterns on 413 consecutive cases of EGFR negative lung carcinoma from March 2016 to April 2017 using FISH for ALK, ROS1, and MET along with ALK (D5F3) IHC.

Results

ROS1 gene rearrangement, ALK positivity (IHC and/or FISH), and MET amplification were seen in 18/358 (5%) cases, 76/392 cases (19.4%), and 10/370 (2.7%) cases, respectively. ALK FISH and ALK IHC were positive in 51/300 (17%) and 58/330 cases (17.57%), respectively, while 8/330 (2.4%) cases were ALK IHC "equivocal" of which 3/8 (37.5%) were ALK FISH positive. Of ALK FISH and IHC co-tested cases, 43/238 (18.07%) cases were positive by both techniques, while 15/43 (34.88%) of ALK positive cases showed discordant ALK FISH and IHC results. All ROS1 rearranged and MET amplified cases were adenocarcinoma. Signet ring cell histology was associated with 78.57% likelihood of being either ALK or ROS1 positive. Genomic heterogeneity was seen in 30% of MET amplified cases.

Conclusions

ALK/ROS1/MET gene alterations were found in 25.18% of NSCLC cases. An ALK IHC "equivocal" interpretation category should be incorporated into practice. Atypical patterns of ROS1 and genomic heterogeneity need to be evaluated further for any clinical relevance.

Clinical Characteristics, Treatments, and Concurrent Mutations in Non-Small Cell Lung Cancer Patients With NF1 Mutations

OBJECTIVES

Metastatic non-small cell lung cancer (mNSCLC) is characterized by complex genomic alterations. NF1 mutations may confer distinct clinical characteristics within NSCLC, and real-world evidence on concurrent mutations, treatment patterns, and health outcomes is lacking.

MATERIALS AND METHODS

This retrospective study was performed in patients with mNSCLC treated in the Flatiron Health network who underwent the FoundationOne tumor-sequencing. Anticancer therapies, concurrent mutations, real-world progression-free survival (rwPFS), and overall survival (OS) were assessed.

RESULTS

Of the 1663 patients, 103 patients were identified with NF1 mutation. Concurrent mutations with Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (16.5%) and epidermal growth factor receptor fusion (6.8%) were the most frequent. In patients with NF1 mutation only (n = 57), 42% were women, 86% patients had smoking history, and 70% had non-squamous cell carcinoma type. Most (51%) of the patients with NF1 mutations received a single line of therapy versus other mutations and the overall treated population (44%). Platinum-based chemotherapy was the predominant first-line therapy, with programmed cell death-1/programmed cell death-ligand-1 inhibitors as subsequent lines of therapy. The NF1 mutation only group had numerically the shortest median rwPFS (82 days) than other mutation groups. Median OS for the NF1 mutation group in first, second, and third lines of therapy was 321, 498, and 210 days, respectively.

CONCLUSIONS

NF1 mutations confer distinct clinical characteristics in patients with mNSCLC. These patients may have different trajectories for progression and survival than seen for other mutations, experience less systemic therapy after first-line therapy, and may have shorter survival.

Molecular Pathology of Primary Non-small Cell Lung Cancer

Lung carcinoma is one of the most common human cancers and is estimated to have an incidence of approximately 2 million new cases per year worldwide with a 20% mortality rate. Lung cancer represents one of the leading causes of cancer related death in the world. Of all cancer types to affect the pulmonary system, non-small cell lung carcinoma comprises approximately 80-85% of all tumors. In the past few decades cytogenetic and advanced molecular techniques have helped define the genomic landscape of lung cancer, and in the process, revolutionized the clinical management and treatment of patients with advanced non-small cell lung cancer. The discovery of specific, recurrent genetic abnormalities has led to the development of targeted therapies that have extended the life expectancy of patients who develop carcinoma of the lungs. Patients are now routinely treated with targeted therapies based on identifiable molecular alterations or other predictive biomarkers which has led to a revolution in the field of pulmonary pathology and oncology. Numerous different testing modalities, with various strengths and limitations now exist which complicate diagnostic algorithms, however recently emerging consensus guidelines and recommendations have begun to standardize the way to approach diagnostic testing of lung carcinoma. Herein we provide an overview of the molecular genetic landscape of non-small cell lung carcinoma, with attention to those clinically relevant alterations which drive management, as well as review current recommendations for molecular testing.

Clinicopathological characteristics of lung adenocarcinoma with compound EGFR mutations

The extensive clinical applications of next-generation sequence analyzers have made uncommon and compound EGFR mutations more prevalent than previously described. However, clinicopathological impacts of compound EGFR mutations in lung adenocarcinoma remain unclear. We earlier examined the presence of compound EGFR mutations primarily in the cis allele by EGFR exon sequencing and droplet digital polymerase chain reaction in 462 completely resected EGFR-mutated adenocarcinomas of the lung and identified 64 tumors with compound mutations. We evaluated clinicopathological characteristics of lung adenocarcinomas with compound EGFR mutations in comparison with cases with common or uncommon single mutations. Among 64 compound EGFR mutations, L858R/E709G (9%) was the most frequent mutation type, followed by L858R/S768I (8%), L858R/T790M (8%), and L858R/L833V (6%). We observed both single and compound mutations frequently in women, never or light smokers; their adenocarcinomas showed thyroid transcription factor-1 immunoreactivity. In contrast, compound mutations were significantly associated with lymph node metastases (p = 0.0242; single vs. compound cases) and the presence of tumor cells with clear cytoplasm (p = 0.0014; single vs. compound cases). Furthermore, patients with compound mutations had significantly poorer prognoses than cases with single EGFR mutations (p = 0.043). Overall, clinicopathological features of common, uncommon, and compound EGFR mutations are similar; however, tumors with compound mutations may be characterized by aggressive behavior and histological findings of clear cell features.

Quantitative volumetric assessment of the solid portion percentage on CT images to predict ROS1/ALK rearrangements in lung adenocarcinomas

In the present study, the predictive role of the percentage of the solid portion volume (PSV) in patients with lung adenocarcinoma was investigated. The PSV was obtained through quantitative volumetric assessments based on reconstructed CT images of lung adenocarcinoma by comparing the index among tumors with c-ros oncogene 1 (ROS1) rearrangement, epidermal growth factor receptor (EGFR) mutations, echinoderm anaplastic lymphoma kinase (ALK) rearrangements or wild-type (WT) status for the three genes. Among 1,120 patients with lung adenocarcinoma, 28 patients with ROS1 rearrangement lung adenocarcinoma, 71 with ALK rearrangement and 578 with EGFR mutations were diagnosed. PSV was quantitatively measured by semi-automated nodule assessment software and compared in patients with different mutation statuses. The PSV (presented as the median with interquartile range) in the ROS1 rearrangement group [87.9 (82.7-92.3)%] was higher than that in the EGFR mutation group [70.4 (51.4-83.4%)] and the WT group [63.0 (50.9-83.2)%; P<0.001], but was similar to that in the ALK rearrangement group [84.0 (70.3-90.0)%; P=0.251]. The area under the receiver operating characteristic curve (AUC) for the PSV to predict ROS1 or ALK rearrangement combined was 0.702 (95% CI: 0.631-0.773; P<0.001); at a cut-off value of 0.805 (when the Youden index was maximal), the predictive sensitivity was 0.697 and the specificity was 0.702. Younger age and higher PSV values were independent predictors of ROS1/ALK rearrangements. The AUC for the predictive model combined with age and PSV was 0.785. In conclusion, the PSV in the lung adenocarcinomas with ROS1 rearrangement was significantly higher compared with that in the EGFR-mutated and WT lung adenocarcinoma, but was similar to that in lung adenocarcinoma with ALK rearrangement. Younger age and higher PSV values on CT in patients with lung adenocarcinomas were predictive factors for ROS1/ALK rearrangement.

Use of Fluorescence In Situ Hybridization (FISH) in Diagnosis and Tailored Therapies in Solid Tumors

Fluorescence in situ hybridization (FISH) is a standard technique used in routine diagnostics of genetic aberrations. Thanks to simple FISH procedure is possible to recognize tumor-specific abnormality. Its applications are limited to designed probe type. Gene rearrangements e.g., ALK, ROS1 reflecting numerous translocational partners, deletions of critical regions e.g., 1p and 19q, gene fusions e.g., COL1A1-PDGFB, genomic imbalances e.g., 6p, 6q, 11q and amplifications e.g., HER2 are targets in personalized oncology. Confirmation of genetic marker is frequently a direct indication to start specific, targeted treatment. In other cases, detected aberration helps pathologists to better distinguish soft tissue sarcomas, or to state a final diagnosis. Our main goal is to show that applying FISH to formalin-fixed paraffin-embedded tissue sample (FFPE) enables assessing genomic status in the population of cells deriving from a primary tumor or metastasis. Although many more sophisticated techniques are available, like Real-Time PCR or new generation sequencing, FISH remains a commonly used method in many genetic laboratories.

Immunization against ROS1 by DNA Electroporation Impairs K-Ras-Driven Lung Adenocarcinomas ​

Non-small cell lung cancer (NSCLC) is still the leading cause of cancer death worldwide. Despite the introduction of tyrosine kinase inhibitors and immunotherapeutic approaches, there is still an urgent need for novel strategies to improve patient survival. ROS1, a tyrosine kinase receptor endowed with oncoantigen features, is activated by chromosomal rearrangement or overexpression in NSCLC and in several tumor histotypes. In this work, we have exploited transgenic mice harboring the activated K-Ras oncogene (K-Ras^G12D) that spontaneously develop metastatic NSCLC as a preclinical model to test the efficacy of ROS1 immune targeting. Indeed, qPCR and immunohistochemical analyses revealed ROS1 overexpression in the autochthonous primary tumors and extrathoracic metastases developed by K-Ras^G12D mice and in a derived transplantable cell line. As proof of concept, we have evaluated the effects of the intramuscular electroporation (electrovaccination) of plasmids coding for mouse- and human-ROS1 on the progression of these NSCLC models. A significant increase in survival was observed in ROS1-electrovaccinated mice challenged with the transplantable cell line. It is worth noting that tumors were completely rejected, and immune memory was achieved, albeit only in a few mice. Most importantly, ROS1 electrovaccination was also found to be effective in slowing the development of autochthonous NSCLC in K-Ras^G12D mice.

Influence of Estrogen on the NSCLC Microenvironment: A Comprehensive Picture and Clinical Implications

Lung cancer mortality represents the leading cause of cancer related deaths in the United States and worldwide. Almost half of these deaths occur in female patients, making lung cancer the most common cause of cancer mortality in women with a higher annual mortality rate than breast, uterine, and ovarian cancers combined. The distinct epidemiological, histological and biological presentation of non-small cell lung cancer (NSCLC) in women combined with extensive preclinical data have demonstrated that the female sex hormone β-estradiol (E2) plays an important role in NSCLC tumorigenesis, prognosis, and treatment response. Estrogen receptors are widely expressed on stromal and immune cells, and estrogen-linked signaling pathways are known to be involved in regulating the response of both the innate and adaptive immune system. Immune evasion has been recognized as a “hallmark” of cancer and immunotherapy has re-defined standard of care treatment for NSCLC. Despite these advancements, the low response rates observed in patients treated with immune checkpoint inhibitors has led to a search for mediators of immunosuppression and ways to augment the action of these agents. We focus on emerging data describing sex differences that modulate immunotherapy efficacy in NSCLC, immunosuppressive properties of E2 that lead to a pro-tumor microenvironment (TME), and the translational potential of altering the immune microenvironment by targeting the estrogen signaling pathway. E2-induced modulation affects multiple cell types within the TME, including cancer-associated fibroblasts, tumor infiltrating myeloid cells, and tumor infiltrating lymphocytes, all of which interplay with lung tumor cells via E2 and estrogen receptor engagement, ultimately shaping the TME that may, in part, be responsible for the sex-based disparities observed in NSCLC. An improved understanding of the role of the estrogen pathway in NSCLC anti-cancer immunity may lead to novel therapeutic approaches for altering the TME to improve the efficacy of immunotherapy agents.

Frequent appearance of club cell (Clara cell)-like cells as a histological marker for ALK-positive lung adenocarcinoma

Anaplastic lymphoma kinase-rearranged (ALK⁺ ) lung cancers show characteristic histological features, such as solid signet ring cell patterns and mucinous cribriform patterns; however, these features are not always observed in ALK⁺ lung cancers. We noticed that club cell (Clara cell)-like cells (CLCs) were frequently present in the papillary portion of ALK⁺ lung adenocarcinomas. In this study, we investigated the importance of CLCs in papillary patterns of ALK⁺ lung cancers. We compared the histological features of 18 ALK⁺ cases with 62 control cases (22 epidermal growth factor receptor-positive (EGFR⁺ ) and 40 ALK- and EGFR-negative (ALK^- /EGFR^- ) cases). The present study analyzed presence of papillary pattern, proportion of papillary pattern area, presence of micropapillary pattern, frequency of CLCs and lengths of snout. The frequency of CLCs in ALK⁺ cases was significantly higher than that in EGFR⁺ cases and ALK^- /EGFR^- cases. Micropapillary pattern was more frequently observed in ALK⁺ cases than that in ALK^- /EGFR^- cases (P < 0.001). The present study indicated that the high frequency of CLCs in papillary patterns was significantly associated with ALK⁺ cases. When solid signet ring cell patterns and mucinous cribriform patterns are absent, the high frequency of CLCs in papillary adenocarcinoma could be a useful histological marker for ALK⁺ lung cancers.

Association with PD-L1 Expression and Clinicopathological Features in 1000 Lung Cancers: A Large Single-Institution Study of Surgically Resected Lung Cancers with a High Prevalence of EGFR Mutation

Programmed cell death ligand 1 (PD-L1) expression is an important biomarker for predicting response to immunotherapy in clinical practice. Hence, identification and characterization of factors that predict high expression of PD-L1 in patients is critical. Various studies have reported the association of PD-L1 expression with driver genetic status in non-small cell cancer; however, the results have been conflicting and inconclusive. We analyzed the relationship between PD-L1 expression and clinicopathological factors including driver genetic alterations in 1000 resected lung cancers using a clinically validated PD-L1 immunohistochemical assay. PD-L1 expression was significantly higher in squamous cell carcinoma (SCC) compared to adenocarcinomas. PD-L1 expression in adenocarcinoma was associated with higher N-stage, solid histologic pattern, EGFR wild type, and ALK positive, but no significant association with the clinicopathological factors in SCC. EGFR mutant adenocarcinomas with distinctive clinicopathologic features, especially solid histologic pattern and higher stage showed higher PD-L1 expression. To the best of our knowledge, this study is the largest to evaluate the association between PD-L1 expression and clinicopathological and molecular features in lung cancer with a highly prevalent EGFR mutation. Therefore, our results are useful to guide the selection of lung cancer, even EGFR-mutated adenocarcinoma patients with PD-L1 expression, for further immunotherapy.

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.

Epidermal Growth Factor Receptor (EGFR) Mutations and Anaplastic Lymphoma Kinase/Oncogene or C-Ros Oncogene 1 (ALK/ROS1) Fusions Inflict Non-Small Cell Lung Cancer (NSCLC) Female Patients Older Than 60 Years of Age

Background

Lung cancer has become a leading disease for the tumor-induced mortality. Non-small cell lung cancer (NSCLC) accounts for approximately 80% of all lung cancers. The present research aimed to evaluate the correlation between the anaplastic lymphoma kinase/oncogene or c-ros oncogene 1 (ALK/ROS1) fusions or mutations of epidermal growth factor receptor (EGFR) and ages or gender of patients.

Material/Methods

Among 1449 NSCLC patients, 457 patients who were diagnosed as consecutive EGFR mutations or ALK/ROS1 fusions between November 2016 and February 2018 were involved in the present study. EGFR genes or ALK/ROS1 mutations were detected by using DNA sequencing technique and amplification-refractory mutation system (ARMS). The mRNAs of ROS1 and ALK fusion were examined by using polymerase chain reaction technique and fusion gene detection kit.

Results

Females were more often inflicted by the EGFR mutations, especially for the exon 19 deletion and L858R mutation. There were significantly more ALK/ROS1 fusions in females compared to males (P<0.05) and significantly more ALK/ROS1 fusions in <60 years of age patients compared to patients older than 60 years of age (P<0.05). Exon 21 L858R and L861Q dominantly occurred in patients ≥60 years of age and exon 19 deletion in patients <60 years of age. EML-ALK-1 mainly existed in the female NSCLC patients.

Conclusions

EGFR mutations and ALK/ROS1 fusions mainly occurred in the NSCLC female patients who were older than 60 years of age.

PD-L1 expression in ROS1-rearranged non-small cell lung cancer: A study using simultaneous genotypic screening of EGFR, ALK, and ROS1

Background

The aim of the current study was to investigate the prevalence and clinicopathologic characteristics of ROS1‐rearranged non‐small cell lung cancer (NSCLC) in routine genotypic screening in conjunction with the study of PD‐L1 expression, a biomarker for first‐line treatment decisions.

Methods

Reflex simultaneous genotypic screening for EGFR by peptide nucleic acid clamping, and ALK and ROS1 by fluorescence in situ hybridization (FISH) was performed on consecutive NSCLC cases at the time of initial pathologic diagnosis. We evaluated genetic aberrations, clinicopathologic characteristics, and PD‐L1 tumor proportion score (TPS) using a PD‐L1 22C3 assay kit.

Results

In 407 consecutive NSCLC patients, simultaneous genotyping identified 14 (3.4%) ROS1 and 19 (4.7%) ALK rearrangements, as well as 106 (26%) EGFR mutations. These mutations were mutually exclusive and were found in patients with similar clinical features, including younger age, a prevalence in women, adenocarcinoma, and advanced stage. The PD‐L1 assay was performed on 130 consecutive NSCLC samples. High PD‐L1 expression (TPS ≥ 50%) was observed in 29 (22.3%) tumors. PD‐L1 expression (TPS ≥ 1%) was significantly associated with wild type EGFR, while ROS1 rearrangement was associated with high PD‐L1 expression. Of the 14 cases with ROS1 rearrangement, 12 (85.7%) showed PD‐L1 expression and 5 (35.7%) showed high PD‐L1 expression.

Conclusion

In the largest consecutive routine Asian NSCLC cohort analyzed to date, we found that high PD‐L1 expression frequently overlapped with ROS1 rearrangement, while it negatively correlated with EGFR mutations.

RNAi-based therapeutics for lung cancer: biomarkers, microRNAs, and nanocarriers

INTRODUCTION

Despite the current advances in the discovery of the lung cancer biomarkers and, consequently, in the diagnosis, this pathology continues to be the primary cause of cancer-related death worldwide. In most cases, the illness is diagnosed in an advanced stage, which limits the current treatment options available and reduces the survival rate. Therefore, RNAi-based therapy arises as a promising option to treat lung cancer.

AREAS COVERED

This review provides an overview on the exploitation of lung cancer biology to develop RNAi-based therapeutics to be applied in the treatment of lung cancer. Furthermore, the review analyzes the main nanocarriers designed to deliver RNAi molecules and induce antitumoral effects in lung cancer, and provides updated information about current RNAi-based therapeutics for lung cancer in clinical trials.

EXPERT OPINION

RNAi-based therapy uses nanocarriers to perform a targeted and efficient delivery of therapeutic genes into lung cancer cells, by taking advantage of the known biomarkers in lung cancer. These therapeutic genes are key regulatory molecules of crucial cellular pathways involved in cell proliferation, migration, and apoptosis. Thereby, the characteristics and functionalization of the nanocarrier and the knowledge of lung cancer biology have direct influence in improving the therapeutic effect of this therapy.

Driver mutations of young lung adenocarcinoma patients with malignant pleural effusion

Young lung cancer patients have several distinct characteristics. However, there are limited epidemiological data of genetic abnormalities in this population. We conducted a prospective cohort study to delineate the various oncogenic driver mutations of lung adenocarcinoma in young Asian patients. We consecutively collected malignant pleural effusions (MPEs) from lung adenocarcinoma patients. RNA was extracted from MPEs for mutation analysis by reverse transcription-polymerase chain reaction and direct sequencing. Selected gene mutations for testing included EGFR, HER2, BRAF, KRAS, PIK3CA, JAK2, MEK1, NRAS, and AKT2 mutations, as well as EML4-ALK, ROS1, and RET fusions. We collected MPEs from 142 patients aged ≤50 years and 730 patients aged >50 years. Patients aged ≤50 years (91%) had a higher incidence of driver gene mutations than those aged >50 years (84%; P = .036), especially EML4-ALK (P < .001) and ROS1 (P < .001). Among patients aged ≤50 years, EGFR mutation was the major oncogenic driver mutation. The mutation rates of other genes were 18% EML4-ALK, 6% ROS1, 5% HER2, 1% RET, 1% BRAF, and 1% KRAS. We did not detect PIK3CA, JAK2, MEK1, NRAS, or AKT2 mutations. No difference in gender or smoking history was noted among those with different driver mutations. Patients who had a good performance status or received appropriate targeted therapy had longer overall survival. In conclusion, lung adenocarcinoma in Asian patients aged ≤50 years had a higher gene mutation rate than in those aged >50 years, especially EML4-ALK and ROS1 fusion. Mutation analysis may be helpful in determining targeted therapy for the majority of these patients.

Lung cancer in never smokers-the East Asian experience

Approximately one third of all lung cancer patients in East Asia are never-smokers. Furthermore, the proportion of lung cancer in never smokers (LCINS) has been increasing over time. Never-smokers are more often diagnosed with adenocarcinoma in East Asia, a subtype largely defined by oncogenic drivers. In this subgroup of patients, as high as 90% of patients have been found to harbor well-known oncogenic mutations and can be successfully managed with targeted therapies inhibiting specific oncogenic mutant kinases. EGFR tyrosine kinase inhibitor (EGFR-TKI) treatment has been the most important targeted therapy in lung adenocarcinoma from East Asian never-smokers as approximately 70% of these patients have the opportunity to receive EGFR-TKI treatment. Lung squamous cell carcinoma (SQCC) and small cell lung cancer (SCLC) are two common histologic types of smoking-related non-small cell lung cancer (NSCLC). The proportion of never-smokers with SQCC and SCLC in East Asian patients seems to be higher than that in Caucasian patients. Recent studies also suggest that lung SQCC and SCLC in never-smokers may be distinct subtypes. Therefore, better understanding of the biologic characteristics of these subtypes of patients may provide new insights for the treatment. In this review, we will provide an overview of East Asian experience in the treatment of advanced, never-smoking lung cancer, focusing on etiologic factors in the development of LCINS, targeted therapy for never-smokers with adenocarcinoma, distinct characteristics of never-smokers with lung SQCC and SCLC, and the role of immunotherapy in never-smokers with NSCLC.

Evolution strategy of ROS1 kinase inhibitors for use in cancer therapy

The abnormal expression of c-ros oncogene1 receptor tyrosine kinase (ROS1) has been identified as clinically actionable oncogenic driver in non-small-cell lung cancer. Since crizotinib was approved by the US FDA for the treatment of advanced ROS1-positive non-small-cell lung cancer, ROS1 kinase has become a promising therapeutic target. Under the guidance of some advanced computer-assisted technologies, such as structure-based drug design, homology modeling and lipophilic efficiency parameters, several potent and selective inhibitors against wild-type and mutant ROS1 were designed and synthesized. In this article, we will review a series of scaffolds targeting ROS1 kinase from the hit-to-drug evolution strategies of their representative compounds and it is hoped that these design strategies would facilitate medicinal chemists to optimize the process of drug design.

Comparison of Molecular Testing Modalities for Detection of ROS1 Rearrangements in a Cohort of Positive Patient Samples

INTRODUCTION

ROS1 gene fusions are a well-characterized class of oncogenic driver found in approximately 1% to 2% of NSCLC patients. ROS1-directed therapy in these patients is more efficacious and is associated with fewer side effects compared to chemotherapy and is thus now considered standard-of-care for patients with advanced disease. Consequently, accurate detection of ROS1 rearrangements/fusions in clinical tumor samples is vital. In this study, we compared the performance of three common molecular testing approaches on a cohort of ROS1 rearrangement/fusion-positive patient samples.

METHODS

Twenty-three ROS1 rearrangement/fusion-positive clinical samples were assessed by at least two of the following molecular testing methodologies: break-apart fluorescence in situ hybridization, DNA-based hybrid capture library preparation followed by next-generation sequencing (NGS), and RNA-based anchored multiplex polymerase chain reaction library preparation followed by NGS.

RESULTS

None of the testing methodologies demonstrated 100% sensitivity in detection of ROS1 rearrangements/fusions. Fluorescence in situ hybridization results were negative in 2 of 20 tested samples, the DNA-based NGS assay was negative in 4 of 18 tested samples, and the RNA-based NGS assay was negative in 3 of 19 tested samples. For all three testing approaches, we identified assay characteristics that likely contributed to false-negative results. Additionally, we report that genomic breakpoints are an unreliable predictor of breakpoints at the transcript level, likely due to alternative splicing.

CONCLUSIONS

ROS1 rearrangement/fusion detection in the clinical setting is complex and all methodologies have inherent limitations of which users must be aware to correctly interpret results.