ALK-rearranged Adenocarcinoma Research Articles

Concordance of Immunohistochemistry and Fluorescence In Situ Hybridization in the Detection of Anaplastic Lymphoma Kinase (ALK) and Ros Proto-oncogene 1 (ROS1) Gene Rearrangements in Non-Small Cell Lung Carcinoma: A 4.5-Year Experience Highlighting Challenges and Pitfalls.

ALK and ROS1 rearrangements are essential biomarkers to be tested in advanced lung adenocarcinomas. While D5F3 Ventana assay is a companion diagnostic for anaplastic lymphoma kinase-targeted therapy, immunohistochemistry is only a screening tool for detecting ROS1 rearrangement. Confirmation by cytogenetic or molecular techniques is necessary. To evaluate the utility of ALK and ROS1 fluorescence in situ hybridization as a complement to immunohistochemistry in routine predictive biomarker testing algorithms. The study was ambispective, spanning 4.5 years during which lung adenocarcinoma samples were subjected to EGFR mutation testing by real-time polymerase chain reaction, and ALK/ROS1 rearrangement testing by immunohistochemistry (Ventana D5F3 assay for anaplastic lymphoma kinase protein; manual assay with D4D6 clone for Ros proto-oncogene 1 protein). Fluorescence in situ hybridization was performed in all anaplastic lymphoma kinase equivocal and Ros proto-oncogene 1 immunopositive cases. Of 1874 samples included, EGFR mutations were detected in 27% (481 of 1796). Anaplastic lymphoma kinase immunohistochemistry was positive in 10% (174 of 1719) and equivocal in 3% (58 of 1719) of samples tested. ALK fluorescence in situ hybridization showed 81% (77 of 95) concordance with immunohistochemistry. Ros proto-oncogene 1 immunopositivity was noted in 13% (190 of 1425) of cases, with hybridization-confirmed rearrangements in 19.3% (26 of 135) of samples, all of which showed diffuse, strong- to moderate-intensity, cytoplasmic staining in tumor cells. Ros proto-oncogene 1 protein overexpression without rearrangement was significantly common in EGFR-mutant and ALK-rearranged adenocarcinomas. Immunostaining is a robust method for ALK-rearrangement testing, with fluorescence in situ hybridization adding value in the rare equivocal stained case. ROS1-rearrangement testing is more cost-effective if immunohistochemistry is followed by fluorescence in situ hybridization after excluding EGFR-mutant and ALK-rearranged adenocarcinomas.

EP14.01-001 SCLC Transformation from ALK-rearranged Lung Adenocarcinoma after Alectinib Resistance and Response to Atezolizumab: Case Report

The genotypic and histological evolution of non-small cell lung cancer (NSCLC) to small cell lung cancer (SCLC) has been described as a mechanism of acquired resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) therapy. However, it is extremely rare in ALK-rearranged adenocarcinomas, and the follow-up care and outcomes of patients in this rare condition are unclear. We describe a unique case in which a patient with ALK-rearranged adenocarcinoma underwent small-cell transformation at a metastatic site with retained ALK rearrangement after alectinib treatment.

Transformation of invasive lung adenocarcinoma with ALK rearrangement into pulmonary sarcomatoid carcinoma

Anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitors (TKIs) improve outcomes for non-small-cell lung cancer (NSCLC) patients with ALK fusions. Nevertheless, ALK TKI resistance will inevitably occur. Histological transformation is one of the causes of TKI resistance in NSCLC. Reports of ALK-rearranged adenocarcinoma with histological transformation are limited. A case of an invasive lung adenocarcinoma patient with ALK rearrangement who experienced histological transformation into sarcomatoid carcinoma after ALK TKI resistance is reported, and ALK fusion, MET amplification and TP53 mutation were detected after transformation. This case first reported a patient with invasive lung adenocarcinoma harboring ALK rearrangement who underwent histological transformation into sarcomatoid carcinoma after ALK TKI resistance, and MET amplification might represent the cause. After transformation, the patient benefited from targeted therapy combined with chemotherapy, which represents a promising option for patients with sarcomatoid carcinoma transformation.

P84.20 VATS Right Upper Lobectomy for Advanced Non-Small Cell Lung Cancer After ALK-Tyrosine Kinase Inhibitor Administration.

Surgical resection is not generally indicated, but systemic chemotherapy or several molecular-targeted agents are selected as main treatments for advanced lung cancer. But as for the molecular-targeted agents, most patients eventually experience tumor progression due to acquired resistance. The role of residual or recurrent tumor resection after the treatment is unclear. A 65 year-old man was referred to our hospital due to abnormal radiographic image. Chest CT revealed a 50mm solid mass in the right upper lobe. The tumor involved hilar lymph node and extended to the junction of upper lobar bronchus. MRI revealed a 20mm brain metastasis in the left parietal lobe. He was initially diagnosed with cT2bN1M1b StageIVA EGFR(-) adenocarcinoma by transbronchial lung biopsy. Then, brain metastasis was removed surgically. He was finally diagnosed with ALK-rearranged adenocarcinoma from tissue of brain metastasis. Alectinib (600mg/day) was started as the first-line therapy. After 14 months of alectinib therapy, chest CT revealed remarkable reduction of the tumor and other two new lesions in the right upper lobe. One was a 10mm nodule close to the scar of primary tumor, which had not found at chest CT from three months ago. The other was a 15mm nodule apart from the scar, which existed before the alectinib treatment and had got larger gradually. PET-CT revealed the high fluorodeoxyglucose (FDG) uptake of only two new lesions. We performed complete VATS right upper lobectomy and mediastinal lymph node dissection for treatment and diagnosis. Histopathlogical diagnoses: No residual viable cell was found in the primary lesion. The lesion close to the scar of the primary lesion was adenocarcinoma (ALK-rearranged), which was thought to be a recurrent lesion because of resemblance to brain metastasis in pathological tissue. The lesion apart from the main lesion was pT1bN0M0 StageIB squamous cell carcinoma, which was thought to be primary lung cancer. Alectinib was continued after the operation, and chest CT shows no sign of recurrence so far. We experienced a VATS right upper lobectomy for advanced non-small cell lung cancer after ALK-tyrosine kinase inhibitor administration.

CT features and disease spread patterns in ROS1-rearranged lung adenocarcinomas: comparison with those of EGFR-mutant or ALK-rearranged lung adenocarcinomas

The purpose of this study was to investigate the differences in CT characteristics and disease spread patterns between ROS1-rearranged adenocarcinomas and epidermal growth factor receptor (EGFR)-mutant or anaplastic lymphoma kinase (ALK)-rearranged adenocarcinomas. Patients with stage IIIb/IV adenocarcinoma with ROS1 rearrangement, EGFR mutations, or ALK rearrangement were retrospectively identified. Two radiologists evaluated CT features and disease spread patterns. A multivariable logistic regression model was applied to determine the clinical and CT characteristics that can discriminate between ROS1-rearranged and EGFR-mutant or ALK-rearranged adenocarcinomas. A cohort of 169 patients was identified (ROS1 = 23, EGFR = 120, and ALK = 26). Compared to EGFR-mutant adenocarcinomas, ROS1-rearranged adenocarcinomas were less likely to have air-bronchogram (p = 0.011) and pleural retraction (p = 0.048) and more likely to have pleural effusion (p = 0.025), pericardial metastases (p < 0.001), intrathoracic and extrathoracic nodal metastases (p = 0.047 and 0.023, respectively), and brain metastases (p = 0.017). Following multivariable analysis, age (OR = 1.06; 95% CI: 1.01, 1.12; p = 0.024), pericardial metastases (OR = 10.50; 95% CI: 2.10, 52.60; p = 0.005), and nodal metastases (OR = 8.55; 95% CI: 1.14, 62.52; p = 0.037) were found to be more common in ROS1-rearranged tumors than in non-ROS1-rearranged tumors. ROS1-rearranged adenocarcinomas appeared as solid tumors and were associated with young age, pericardial metastases and advanced nodal metastases relative to tumors with EGFR mutations or ALK rearrangement.

Molecular Targeted Therapies Elicit Concurrent Apoptotic and GSDME-Dependent Pyroptotic Tumor Cell Death.

The induced death signals following oncogene inhibition underlie clinical efficacy of molecular targeted therapies against human cancer, and defects of intact cell apoptosis machinery often lead to therapeutic failure. Despite potential importance, other forms of regulated cell death triggered by pharmacologic intervention have not been systematically characterized. Pyroptotic cell death was assessed by immunoblot analysis, phase-contrast imaging, scanning electron microscopy, and flow cytometry. Tumor tissues of patients with lung cancer were analyzed using IHC. Functional impact of pyroptosis on drug response was investigated in cell lines and xenograft models. We showed that diverse small-molecule inhibitors specifically targeting KRAS-, EGFR-, or ALK-driven lung cancer uniformly elicited robust pyroptotic cell death, in addition to simultaneously invoking cellular apoptosis. Upon drug treatment, the mitochondrial intrinsic apoptotic pathway was engaged and the mobilized caspase-3 protease cleaved and activated gasdermin E (GSDME, encoded by DFNA5), which permeabilized cytoplasmic membrane and executed cell-lytic pyroptosis. GSDME displayed ubiquitous expression in various lung cancer cell lines and clinical specimens, including KRAS-mutant, EGFR-altered, and ALK-rearranged adenocarcinomas. As a result, cooccurrence and interplay of apoptosis and pyroptosis were widespread in lung cancer cells, succumbing to genotype-matched regimens. We further demonstrated that pyroptotic cell death partially contributed to the drug response in a subset of cancer models. These results pinpoint GSDME-dependent pyroptosis as a previously unrecognized mechanism of action for molecular targeted agents to eradicate oncogene-addicted neoplastic cells, which may have important implications for the clinical development and optimal application of anticancer therapeutics.

PC04.03 Adjuvant Targeted Therapy for PTS with Genomic Alterations - Yes

PC04.03 Adjuvant Targeted Therapy for PTS with Genomic Alterations - Yes

Major pathologic response to alectinib in ALK-rearranged adenocarcinoma of the lung

BackgroundAlectinib is a highly selective tyrosine kinase inhibitor of anaplastic lymphoma kinase (ALK) and provided a significantly prolonged progression-free survival compared with chemotherapy in patients with advanced non-small cell lung cancer (NSCLC) harboring rearrangements of the ALK gene. Here, we present the first surgical case of ALK-rearranged lung adenocarcinoma with major pathological response in resected specimens after treatment with alectinib.Case presentationA 65-year-old female with clinical stage IIIA-N2 ALK-rearranged adenocarcinoma originating from the left lower lobe presented. Involvement of lower para-tracheal node was pathologically confirmed by endobronchial ultrasound-guided biopsy. Alectinib was prescribed, as the patient may not tolerate radiotherapy due to a mental illness. After 3 months’ treatment with alectinib, a remarkable radiological and metabolic response was achieved. The patient did not tolerate further continuation of alectinib treatment, and surgery was performed without any morbidity. Only < 10% tumor cells were viable in all resected specimens, indicating major pathological response to alectinib.ConclusionsSalvage surgery after alectinib treatment may be safe and effective for initially unresectable NSCLC harboring ALK-rearrangements.

ALK-rearranged adenocarcinoma transformed to small-cell lung cancer: a new entity with specific prognosis and treatment?

Driving molecular mutations such as rearrangement of ALK and EGFR mutation is present in 5-10% of non-small-cell lung cancer. Tyrosine kinase inhibitors have shown good efficacy and thus become the standard of care. However, tumors have developed several resistance mechanisms against tyrosine kinase inhibitors, including transformation to small-cell lung carcinoma (SCLC). Transformation to SCLC after administration of anti-EGFR in EGFR-mutated adenocarcinoma has been well documented. Similarly, it appears that the same transformation happens in ALK-rearranged adenocarcinoma after the use of anti-ALK. In fact, to date eight cases have been reported in the literature. We aimed in this paper to focus on the characteristics, prognosis and treatment of these transformed SCLC.

ALK rearrangement in specific subtypes of lung adenocarcinoma: immunophenotypic and morphological features.

Lung adenocarcinomas are characterized by a variety of genetic and epigenetic changes that lead to activation of specific signaling pathways. This allowed the classification of lung adenocarcinomas according to genetic alterations and the clinical development of novel anticancer agents that affect the activity of specific oncoproteins. In such a context, chromosomal rearrangements that cause constitutive activation of ALK gene define a category of lung adenocarcinomas that is amenable to targeted therapy with ALK inhibitors. Thus, a major issue of current research is to define the morphological and immunophenotypic features of lung ALK-rearranged adenocarcinomas to improve the selection of tumors suitable for molecular genotyping. ALK status was determined, by immunohistochemistry and fluorescence in situ hybridization, in 94 surgically resected lung adenocarcinomas and correlated with histomorphological parameters. Indeed, ALK rearrangement was observed in 10/94 (11%) lung adenocarcinomas and enriched in tumors with a predominant mucinous (46%; p<0.05) and solid (29%; p<0.05) pattern. By contrast, it was lacking or sporadically observed in lung adenocarcinomas with predominant acinar, papillary or lepidic pattern. Moreover, the presence of signet-ring cells was predominantly observed in ALK-rearranged tumors (47%; p<0.05). These data suggest that ALK rearrangement is associated with specific and distinct clinical-pathological characters compared to other genotypes. Thus, the knowledge of these characteristics can improve the diagnostic accuracy and lead to a better understanding of the behavior of ALK-rearranged NSCLC.

Pulmonary adenocarcinoma with mucin production modulates phenotype according to common genetic traits: a reappraisal of mucinous adenocarcinoma and colloid adenocarcinoma.

Whether invasive mucinous adenocarcinoma (IMA) and colloid adenocarcinoma (ICA) of the lung represent separate tumour entities, or simply lie within a spectrum of phenotypic variability, is worth investigating. Fifteen ICA, 12 IMA, 9 ALK‐rearranged adenocarcinomas (ALKA), 8 non‐mucinous KRAS‐mutated adenocarcinomas (KRASA) and 9 mucinous breast adenocarcinomas (MBA) were assessed by immunohistochemistry for alveolar (TTF1, cytoplasmic MUC1), intestinal (CDX‐2, MUC2), gastric (membrane MUC1, MUC6), bronchial (MUC5AC), mesenchymal (vimentin), neuroendocrine (chromogranin A, synaptophysin), sex steroid hormone‐related (oestrogen and progesterone receptors), pan‐mucinous (HNF4A) and pan‐epithelial (keratin 7) lineage biomarkers and by targeted next generation sequencing (TNGS) for 50 recurrently altered cancer genes. Unsupervised clustering analysis using molecular features identified cluster 1 (IMA and ICA), cluster 2 (ALKA and KRASA) and cluster 3 (MBA) (p < 0.0001). Cluster 1 showed four histology‐independent sub‐clusters (S1 to S4) pooled by HFN4A and MUC5AC but diversely reacting for TTF1, MUC1, MUC2, MUC6 and CDX2. Sub‐cluster S1 predominantly featured intestinal‐alveolar, S2 gastrointestinal, S3 gastric and S4 alveolar differentiation. In turn, KRASA and ALKA shared alveolar lineage alongside residual MUC5AC expression, with additional focal CDX2 and diffuse vimentin, respectively. A proximal‐to‐distal scheme extending from terminal (TB) and respiratory (RB) bronchioles to alveolar cells was devised, where S3 originated from distal TB (cellular mucinous adenocarcinoma), S2 from proximal RB (secreting mucinous adenocarcinoma), S1 from intermediate RB (mucin lake‐forming colloid adenocarcinoma), S4 from distal RB (colloid alveolar adenocarcinoma), KRASA from juxta‐alveolar RB (KRAS‐mutated non‐mucinous adenocarcinoma) and ALKA from juxta‐bronchial alveolar cells (ALK‐translocated adenocarcinoma). TNGS analysis showed KRAS, LKB1, TP53, APC and CDKN2A mutation predominance. In conclusion, IMA and ICA are basket categories, which likely originate from distinct domains of stem/progenitor cells spatially distributed along bronchioles upon common molecular features and genetic alterations.

印環細胞を主体としたALK陽性肺腺癌の1例

症例は63歳，男性．検診で胸部異常陰影を指摘され，外来を受診した．胸部CTで右肺下葉に結節影を認め，肺癌を疑い，画像上，遠隔転移を認めず，手術の方針となった．胸腔鏡下右肺下葉切除術，縦隔リンパ節郭清（ND2a-1）を施行した．病理診断は，印環細胞成分を60％含む，腺癌であった．上部消化管内視鏡で胃癌を認めず，免疫染色ではTTF-1陽性，CK-7陽性，CK-20陰性であり，原発性肺癌と診断した．また，ALK遺伝子変異を認めた．印環細胞成分を含む，原発性肺癌は比較的稀であるが，高率にALK遺伝子変異陽性であることが知られ，ALK阻害剤が有効である点で臨床的に極めて重要であり，報告する．

Co-clinical quantitative tumor volume imaging in ALK-rearranged NSCLC treated with crizotinib

PurposeTo evaluate and compare the volumetric tumor burden changes during crizotinib therapy in mice and human cohorts with ALK-rearranged non-small-cell lung cancer (NSCLC). MethodsVolumetric tumor burden was quantified on serial imaging studies in 8 bitransgenic mice with ALK-rearranged adenocarcinoma treated with crizotinib, and in 33 human subjects with ALK-rearranged NSCLC treated with crizotinib. The volumetric tumor burden changes and the time to maximal response were compared between mice and humans. ResultsThe median tumor volume decrease (%) at the maximal response was −40.4% (range: −79.5%–+11.7%) in mice, and −72.9% (range: −100%–+72%) in humans (Wilcoxon p=0.03). The median time from the initiation of therapy to maximal response was 6 weeks in mice, and 15.7 weeks in humans. Overall volumetric response rate was 50% in mice and 97% in humans. Spider plots of tumor volume changes during therapy demonstrated durable responses in the human cohort, with a median time on therapy of 13.1 months. ConclusionThe present study described an initial attempt to evaluate quantitative tumor burden changes in co-clinical imaging studies of genomically-matched mice and human cohorts with ALK-rearranged NSCLC treated with crizotinib. Differences are noted in the degree of maximal volume response between the two cohorts in this well-established paradigm of targeted therapy, indicating a need for further studies to optimize co-clinical trial design and interpretation.

Clinical outcomes in ALK-rearranged lung adenocarcinomas according to ALK fusion variants.

BackgroundClinical outcomes of anaplastic lymphoma kinase (ALK)-rearranged non-small cell lung cancer according to ALK fusion variants are not clear. We aimed to investigate the prevalence of ALK fusion variants and to compare clinical outcomes according to ALK fusion variants.MethodsA retrospective analysis was conducted on patients with advanced ALK-rearranged adenocarcinoma treated with chemotherapy and ALK inhibitors. ALK rearrangement was identified by fluorescence in situ hybridization and confirmed by immunohistochemistry. Peptide nucleic acid-mediated quantitative polymerase chain reaction assays, designed to detect 28 types of echinoderm microtubule-associated protein-like 4 (EML)-ALK rearrangements, were performed. Clinicopathological analysis and treatment outcomes with platinum-based chemotherapy, pemetrexed therapy, and ALK inhibitors—including crizotinib and ceritinib—were evaluated.ResultsA total of 52 patients with ALK-rearranged lung adenocarcinoma were enrolled. EML4-ALK variant 1 (v1) was the most common variant (38.5 %) followed by the non-EML4 variant (36.5 %), EML4-ALK variant 3a/b (19.2 %), and EML4-ALK variant 2 (5.8 %). No clinicopathological distinction was found between the different ALK fusion variants. Treatment response rates for each therapeutic agent did not differ according to ALK fusion variant. However, EML4 variants, especially v1, showed significantly longer progression-free survival (PFS) on pemetrexed treatment than did non-EML4 variants (median 31.1 months versus 5.7 months, P = 0.003). PFS with platinum-based chemotherapy and ALK inhibitors did not differ according to ALK fusion variant. Multivariate survival analysis using Cox’s regression model revealed v1 as the only predictive factor for prolonged PFS on pemetrexed.ConclusionsAmong ALK fusion variants, v1 is the most common subtype. It showed superior progression-free survival on pemetrexed than did non-EML4 variants. No survival difference was demonstrated between variants treated with crizotinib or ceritinib.Electronic supplementary materialThe online version of this article (doi:10.1186/s12967-016-1061-z) contains supplementary material, which is available to authorized users.

ALK-rearranged pulmonary adenocarcinoma in Thai Patients: From diagnosis to treatment efficacy.

BackgroundAnaplastic lymphoma kinase (ALK) gene rearrangement is detected in 3 % to 13 % of non-small cell lung carcinoma patients, and these patients benefit from ALK inhibitors. The aim of this study was to determine the prevalence, the clinical and histological characteristics and the treatment outcomes of ALK-rearranged lung adenocarcinoma using immunohistochemistry (IHC) IHC, reverse transcription polymerase chain reaction (RT-PCR) and fluorescence in situ hybridization (FISH) methodologies.MethodsA total of 268 pulmonary adenocarcinoma patients were screened for ALK expression by ALK IHC, which was confirmed by FISH and/or RT-PCR for ALK gene rearrangement. The treatment outcomes of ALK-rearranged patients were retrospectively reviewed.ResultsALK gene rearrangement was identified in 26 cases (9.7 %) with no EGFR co-mutation, and it showed significant associations with younger age, female sex and non-smoker status (p < 0.05). A cribriform growth pattern was identified as the dominant histologic feature, and a solid signet ring cell component was focally present in a minority of the cases. Among 12 ALK-rearranged patients with conventional treatment, seven cases in the early stage of disease were cured and alive, and five patients in the late stage of the disease progressed and died, with a median overall survival (OS) at 14 months. Of the 14 patients receiving crizotinib, all of them had clinical benefit from crizotinib treatment, with one patient having a complete response (CR), 12 patients having a partial response (PR) and one patient having stable disease (SD). On the cutoff date, six of 14 patients were continuing crizotinib treatment with a median time of response of 7.5 (3–13) months, while eight patients had disease progression, and five of them died with a median OS at 8 months.ConclusionALK gene rearrangement tended to occur in younger, non-smoking, female patients. ALK IHC is a reliable screening method to detect ALK gene rearrangement. Crizotinib therapy provided treatment benefit in ALK-rearranged adenocarcinoma patients especially in advanced stages of the disease.

ALK-rearranged adenocarcinoma with extensive mucin production can mimic mucinous adenocarcinoma: clinicopathological analysis and comprehensive histological comparison with KRAS-mutated mucinous adenocarcinoma

We aimed to investigate clinicopathological features and histology of ALK-rearranged adenocarcinomas with extensive mucin production (AEM) that mimic mucinous adenocarcinoma (MA). Retrospectively, 12 cases of AEM and 25 cases of MA harbouring KRAS mutation were retrieved. The clinicopathological profile and detailed histological features were analysed and compared based on the ALK and KRAS status. AEMs occurred in younger patients (p= 0.044) and were characterised by floating tubulopapillary pattern (p < 0.001), prominent nucleolus (p < 0.001), and apical cytoplasmic snouts (p < 0.001). In contrast, KRAS-mutated MAs lacked ALK-specific histological patterns (p < 0.05). Instead, tumour-infiltrating leukocytes (p= 0.018) and smooth cytoplasmic borders (p < 0.001) with vesicular nuclei (p= 0.004) were prominent in KRAS-mutated MAs. AEMs demonstrated characteristic tubulopapillary pattern and apical snouts, which were distinguishing features from MAs with KRAS mutation. Apical snouts can be a useful histological surrogate for ALK rearrangement in the pulmonary adenocarcinomas showing extensive mucin that mimic MA.

A Comprehensive Comparative Analysis of the Histomorphological Features of ALK-Rearranged Lung Adenocarcinoma Based on Driver Oncogene Mutations: Frequent Expression of Epithelial-Mesenchymal Transition Markers than Other Genotype

Molecular classification of lung cancer correlates well with histomorphological features. However, specific histomorphological features that differentiate anaplastic lymphoma kinase (ALK)-rearranged tumors from ALK-negative tumors have not been fully evaluated. Eighty ALK-rearranged and 213 ALK-negative (91 epidermal growth factor receptor-mutated; 29 K-ras-mutated; 93 triple-negative) resected lung adenocarcinomas were analyzed for several histomorphological parameters and histological subtype. ALK-rearranged tumors were associated with younger age at presentation, frequent nodal metastasis, and higher stage of disease at diagnosis. ALK-rearranged tumors were more likely to show a solid predominant pattern than ALK-negative tumors (43.8%; 35/80; p<0.001). Unlike ALK-negative tumors, a lepidic predominant pattern was not observed in ALK-rearranged tumors (p<0.001). In multivariate analysis, the most significant morphological features that distinguished ALK-rearranged tumors from ALK-negative tumors were cribriform formation (odds ratio [OR], 3.253; p = 0.028), presence of mucin-containing cells (OR, 4.899; p = 0.008), close relationship to adjacent bronchioles (OR, 5.361; p = 0.001), presence of psammoma bodies (OR, 4.026; p = 0.002), and a solid predominant pattern (OR, 13.685; p = 0.023). ALK-rearranged tumors exhibited invasive histomorphological features, aggressive behavior and frequent expression of epithelial-mesenchymal transition markers (loss of E-cadherin and expression of vimentin) compared with other genotype (p = 0.015). Spatial proximity between bronchus and ALK-rearranged tumors and frequent solid histologic subtype with p63 expression may cause diagnostic difficulties to differentiate squamous cell carcinoma in the small biopsy, whereas p40 was rarely expressed in ALK-rearranged adenocarcinoma. Knowledge of these features may improve the diagnostic accuracy and lead to a better understanding of the characteristic behavior of ALK-rearranged tumors.

Abstract LB-437: Co-amplification of ALK and c-MET in a subset of pulmonary sarcomatoid carcinoma (PSC)

Abstract The prevalence of ALK gene alterations for targeted therapy with specific inhibitors is a largely unexplored issue in pulmonary sarcomatoid carcinoma (PSC), a life-threatening tumor subset whose treatment still is disappointing. ALK gene status by fluorescence in situ hybridization (FISH) and protein expression by immunohistochemistry (IHC) were carried out on formalin-fixed, paraffin-embedded material from 34 PSC. Fifty-one consecutive metastatic lung adenocarcinomas (MELAD) were also assessed in parallel for ALK with both FISH and IHC. While no rearrangements of ALK gene were detected in PSC, relevant amplification was identified in 6/34 (18%) tumors, while other genes known to behave as driver mutations according to an oncogene addiction criterion, such as EGFR, KRAS, HER2, BRAF, PIK3CA and CTNNB1, were consistently lacking. The percentage of amplified tumor cells ranged from 11% to 43%, with a mean gene copy gain (GCG) ± standard deviation (SD) of 7.5 ± 1.5. We have also investigated 51 MELAD observing that, while 10 of them showed the expected ALK rearrangement (p=0.012), only 1/51 showed the gene amplification (p=0.015). No cases of ALK-amplified tumors, either PSC or adenocarcinoma, expressed the relevant protein, whereas it was otherwise detectable in all ALK-rearranged adenocarcinomas. Interestingly all ALK-amplified tumors, either PSC or adenocarcinoma, showed also c-MET amplification consisting of variably sized clusters of specific signals, whereas negative tumors, regardless of histology, and ALK-rearranged adenocarcinomas did not show c-MET alteration. ALK and c-MET gene amplification clustered into a significant subset of elderly, smoking, predominantly male PSC patients, revealing significant differences with lung adenocarcinoma These encouraging data, however, need to be reinforced on a wider series of tumors in order to elucidate this issue, which could potentially lead to a truly effective treatment of these so life-threatening tumors. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr LB-437. doi:1538-7445.AM2012-LB-437

Clinicopathologic implication of ALK rearrangement in surgically resected lung cancer: A proposal of diagnostic algorithm for ALK-rearranged adenocarcinoma

BackgroundTo characterize the clinicopathologic features of ALK-rearranged lung cancer, and suggest a molecular test protocol for lung adenocarcinoma in the small biopsy specimen. MethodsIn 735 NSCLC surgical specimens, clinicopathologic features, ALK protein over-expression by immunohistochemistry (IHC), and ALK rearrangement by fluorescence in situ hybridization (FISH) as well as EGFR and KRAS mutation studies were analyzed. ResultsOf the 735 NSCLC cases, 28 (3.8%) were ALK FISH-positive. ALK rearrangement, EGFR and KRAS mutation were mutually exclusive. ALK rearrangement was significantly higher in adenocarcinomas (6.8%, p<0.001), younger age (p<0.0007), women (7.6%, p<0.001), and never-smokers (8.9%, p<0.001) with no gender difference in the adenocarcinoma or never-smoker subgroup. ALK FISH-positivity was not associated with disease recurrence (HR, 0.79; 95% CI, 0.42–1.49) or overall survival (HR, 0.61; 95% CI, 0.24–1.55). However, ALK-rearranged lung cancer tended to show more frequent lymph node metastasis despite its lower T stage. Similar to EGFR-mutated lung cancer, ALK-rearranged lung cancer was enriched in adenocarcinoma, women, and never-smokers. The results of ALK IHC and FISH obtained from tissue microarray (TMA)/biopsy specimens and whole sections after resection were concordant. ConclusionALK rearrangement was not a significant prognostic factor in surgically resectable NSCLC. The clinical profiles of ALK-rearranged lung cancer patients overlapped with those of EGFR-mutated patients. Therefore, we suggest that simultaneous tests for ALK IHC and EGFR mutation (Chung's SNUBH molecular test protocol), which has important implications for the storage and use of small biopsy or cytology samples for genetic analysis.