ALK-positive histiocytosis: Report of a rare case with exclusive involvement of the central nervous system in an adult woman.

ALK-positive histiocytosis is a rare histiocytic disease characterized by ALK positivity. It was first described in 2008 as a systemic disease in infants. The disease often shows positivity for CD68 and CD163 on immunohistochemistry, and genomic analysis frequently reveals KIF5B::ALK fusions. ALK-positive histiocytosis typically follows an indolent course and has a promising prognosis, with conventional treatments usually being effective. Here, we report a rare case of ALK-positive histiocytosis with exclusive involvement of the central nervous system in a 33-year-old Asian adult woman. Although cranial MRI suggested a meningioma, immunohistochemical workup showed that the ALK-positive tumor cells expressed macrophage/histiocyte markers such as CD163 and CD68. Additionally, second-generation sequencing revealed a KIF5B::ALK fusion. Our case highlights the importance of the differential diagnosis in adult central nervous system tumors, emphasizing the combination of morphology, immunophenotype, and molecular approach with ALK status evaluation to confirm a diagnosis of ALK-positive histiocytosis. This case also expands the clinicopathologic spectrum of ALK-positive histiocytosis.

Recurrent Inflammatory Myofibroblastic Tumor of Larynx Harboring a Novel THBS1::ALK Fusion.

Inflammatory myofibroblastic tumor (IMT) is a rare soft tissue tumor primarily occurring in the abdominopelvic region of young patients, and it is characterized by spindle-shaped myofibroblasts, or fibroblasts surrounded by inflammatory infiltrate. Herein, we report a case of a 24-year-old male with a firm submucosal mass in the anterior right vocal fold diagnosed as an IMT that recurred 14 months later. The tumor demonstrated a novel THBS1::ALK fusion containing Exons 1-7 of the thrombospondin 1 (THBS1) gene fused to Exon 19 of the anaplastic lymphoma kinase (ALK) gene via next-generation sequencing with the NextSeq sequencer. The fusion of THBS1 to ALK potentially results in increased expression and constitutive activation of the ALK kinase domain. These findings not only broaden the repertoire of known ALK fusion partners implicated in tumorigenesis but also provide a novel avenue for investigating the etiology of recurrent IMT by considering this fusion event as a causal factor. To our knowledge, this is the second case of IMT of the larynx with this novel mutation reported in the literature and the first such case with a detailed description of this specific fusion and clinical recurrence.

Impact of EML4-ALK Variants and Co-Occurring TP53 Mutations on Duration of First-Line ALK Tyrosine Kinase Inhibitor Treatment and Overall Survival in ALK Fusion-Positive NSCLC: Real-World Outcomes From the GuardantINFORM database.

INTRODUCTION: Tyrosine kinase inhibitors (TKIs) are first-line treatment options for ALK-positive (ALK+) NSCLC. Factors such as variant allele frequencies (VAFs), EML4-ALK fusion variant, and concurrent TP53 mutations (TP53mt) in circulating tumor DNA (ctDNA) may affect treatment outcomes. We evaluated their effects on time to discontinuation (TTD) of first-line treatment with next-generation ALK TKIs in a real-world setting. METHODS: Adults with advanced or metastatic NSCLC and ctDNA-detected ALK fusion who received first-line next-generation ALK TKI monotherapy were identified in GuardantINFORM. Effects of ALK fusion VAF, EML4-ALK variants, and TP53mt detection on TTD were evaluated. RESULTS: A total of 307 patients with ALK fusion in baseline ctDNA received first-line alectinib (n = 280), brigatinib (n = 15), lorlatinib (n = 9), or ceritinib (n = 3); 150 patients (49%) had ALK-fusion VAF greater than or equal to 1%. Among 232 patients with EML4-ALK fusions (v1, 50%; v3, 36%), TP53mt co-occurred with v1 in 42 (18%) and v3 in 32 (14%). Patients with VAF less than 1% versus greater than or equal to 1% had a median TTD of 32.2 (95% confidence interval [CI]: 20.7-not estimable [NE]) versus 14.7 months (10.4-19.9; hazard ratio [HR] = 1.57 [95% CI: 1.09-2.26]; p = 0.0146). Median TTD was 13.1 (9.5-19.9) versus 27.6 months (17.3-NE) in patients with versus without TP53mt detected (HR = 1.53 [1.07-2.19]; p = 0.0202) and 20.3 (14.4-NE) versus 11.5 months (7.4-31.1) in patients with v1 versus v3 (HR = 1.29 [0.83-2.01]; p = 0.2641). Patients with TP53mt and v3 had a median TTD of 7.4 months (95% CI: 4.2-31.1). CONCLUSION: High ctDNA VAF, EML4-ALK v3, and TP53mt were associated with early discontinuation of first-line ALK TKIs.

ALK fusion small cell transformation of lung adenocarcinoma: A case report and literature review. / ALKèžåˆè‚ºè ºç™Œå°ç»†èƒžè½¬åŒ–1ä¾‹å¹¶æ–‡çŒ®å¤ä¹ .

Patients with anaplastic lymphoma kinase (ALK) fusion lung adenocarcinoma may develop drug resistance after treatment with ALK-tyrosine kinase inhibitor (ALK-TKI), and the mechanisms of this resistance are not yet fully defined. The Affiliated Hospital of Zunyi Medical University admitted a patient who was resistant to ALK fusion after ALK-TKI treatment, leading to disease progression and subsequent biopsy indicating a transformation to small cell lung cancer in September 2021. The patient, a 54-year-old female, initially presented with symptoms of cough, sputum production, and chest pain for 4 months. Chest CT showed a neoplastic lesion in the posterior segment of the right upper lobe to right lower lobe with obstructive pneumonia, metastasis in the right lower lobe, increased and enlarged mediastinal and right hilar lymph nodes, and thickening of the right hilar soft tissue. Bronchoscopy and pathological biopsy confirmed the diagnosis of lung adenocarcinoma. The results of next-generation sequencing indicated that echinoderm microtubule associated protein like 4-anaplastic lymphoma kinase (EML4-ALK) fusion is associated with tumor protein 53 (TP53) and retinoblastoma 1 (RB1) gene mutations. The patient received second-generation ALK-TKI aletinib, achieving a progression-free survival of 11 months before disease progression suggested aletinib resistance. Subsequently, the third-generation ALK-TKI lorlatinib administered for one month without efficacy, resulting in rapid systemic disease progression. The neuron specific enolase (NSE) was significantly increased, and the patient developed new pleural, pericardial, intracranial, liver, and multiple bone metastases occurred in a short period. A second biopsy indicated small cell lung cancer. Modification of treatment regimen to chemotherapy combined with immunotherapy proved effective. The mechanisms of drug resistance of ALK-TKI treatment for advanced non-small cell lung cancer with ALK fusion are complex, and small cell transformation of pathological type is one such mechanism, although rare. Concurrent TP53 and RB1 gene mutations may be characteristic of this transformation. Elevated NSE can serve as a predictive serum marker for adenocarcinoma transforming to small cell carcinoma. Timely re-biopsy and selection of subsequent treatments based on different resistance mechanisms are crucial for comprehensive disease management.

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.

Antineoplastic Effect of ALK Inhibitor Crizotinib in Primary Human Anaplastic Thyroid Cancer Cells with STRN-ALK Fusion In Vitro.

Anaplastic thyroid cancer (ATC) is one of the deadliest human cancers and represents <2% of thyroid carcinomas. A therapeutic target for ATC is represented by anaplastic lymphoma kinase (ALK) rearrangements, involved in tumor growth. Crizotinib is an oral small-molecule tyrosine kinase inhibitor of the ALK, MET, and ROS1 kinases, approved in ALK-positive non-small cell lung cancer. Until now, the effect of crizotinib in "primary human ATC cells" (pATCs) with transforming striatin (STRN)-ALK fusion has not been reported in the literature. In this study, we aimed to obtain pATCs with STRN-ALK in vitro and evaluate the in vitro antineoplastic action of crizotinib. Thyroid surgical samples were obtained from 12 ATC patients and 6 controls (who had undergone parathyroidectomy). A total of 10/12 pATC cultures were obtained, 2 of which with transforming STRN-ALK fusion (17%). Crizotinib inhibited proliferation, migration, and invasion and increased apoptosis in 3/10 pATC cultures (2 of which with/1 without STRN-ALK), particularly in those with STRN-ALK. Moreover, crizotinib significantly inhibited the proliferation of AF cells (a continuous cell line obtained from primary ATC cells). In conclusion, the antineoplastic activity of crizotinib has been shown in human pATCs (with STRN-ALK) in preclinical studies in vitro, opening the way to future clinical evaluation in these patients.

Comparing Genomic Profiles of ALK Fusion-Positive and ALK Fusion-Negative Nonsmall Cell Lung Cancer Patients.

Background Anaplastic lymphoma kinase ( ALK ) fusion events account for 3 to 7% of genetic alterations in patients with nonsmall cell lung cancer (NSCLC). This study aimed to explore the landscape of ALK fusion-positive and ALK fusion-negative in a large cohort of NSCLC patients. Methods The formalin-fixed paraffin-embedded specimens of NSCLC patients who underwent next-generation sequencing from 2020 to 2023 in Yinfeng Gene Technology Co., Ltd. Clinical laboratory were included in this study. Results In the current study, a total of 180 (3.20%) patients tested positive for ALK fusions in 5,622 NSCLC samples. Within the ALK -positive cohort, a total of 228 ALK fusions were identified. Furthermore, five novel ALK fusion partners, including DAB1-ALK , KCMF1-ALK , KIF13A-ALK , LOC643770-ALK , and XDH-ALK were identified. In cases with ALK fusion-positive, TP53 alterations were the most prevalent (26.3%), followed by CDKN2A (8.4%), epidermal growth factor receptor ( EGFR , 5.6%), and ALK (5.6%). By contrast, EGFR alterations were most prevalent (51%) in patients with ALK fusion-negative NSCLC, followed by TP53 (42.7%), KRAS (11.6%), and CDKN2A (11.3%). A total of 10 cases where ALK fusion co-occurred with EGFR mutations were also identified. Notably, the ALK fusion positivity rate was higher in younger patients ( p < 0.0001) and in female patients ( p = 0.0429). Additionally, positive ALK test results were more prevalent in patients with high programmed death-ligand 1 expression, especially when applying a 50% cutoff. Conclusions Collectively, these findings offer valuable genomic insights that could inform the personalized clinical care of patients with NSCLC harboring ALK fusions within the context of precision medicine.

Primary lung adenocarcinoma with breast metastasis harboring the EML4­ALK fusion: A case report.

Pulmonary adenocarcinoma with breast metastasis is rarely encountered in clinical practice. Therefore, precise clinical diagnosis of patients with this disease is crucial when selecting subsequent treatment modalities and for overall prognosis assessment. The present study reported on a case of lung cancer with breast metastasis harboring the EML4-ALK fusion. The patient was initially diagnosed with triple-negative breast cancer with lung metastasis, but comprehensive breast cancer treatment was ineffective. Reevaluation of the patient's condition via lung biopsy revealed primary lung adenocarcinoma. In addition, the results of genetic testing revealed the EML4-ALK fusion protein in both lung and breast tissues. After treatment with ALK inhibitors, the patient's symptoms improved rapidly. This case highlights the prolonged diagnostic journey from presentation with a breast mass to ultimately being diagnosed with lung cancer with breast metastasis, underscoring the critical need for heightened awareness among clinicians regarding the possibility of rare metastatic patterns. Timely identification of lung cancer with breast metastasis, facilitated by comprehensive genetic testing, not only refines treatment decisions but also emphasizes the importance of interdisciplinary collaboration in navigating complex clinical scenarios. Such insight contributes to the ongoing development of personalized cancer care that guides clinicians toward more effective and tailored therapeutic strategies for patients with similar diagnostic challenges.

Multicenter evaluation of an automated, multiplex, RNA-based molecular assay for detection of ALK, ROS1, RET fusions and MET exon 14 skipping in NSCLC.

The current study assessed the performance of the fully automated RT-PCR-based Idylla™ GeneFusion Assay, which simultaneously covers the advanced non-small cell lung carcinoma (aNSCLC) actionable ALK, ROS1, RET, and MET exon 14 rearrangements, in a routine clinical setting involving 12 European clinical centers. The Idylla™ GeneFusion Assay detects fusions using fusion-specific as well as expression imbalance detection, the latter enabling detection of uncommon fusions not covered by fusion-specific assays. In total, 326 archival aNSCLC formalin-fixed paraffin-embedded (FFPE) samples were included of which 44% were resected specimen, 46% tissue biopsies, and 9% cytological specimen. With a total of 179 biomarker-positive cases (i.e., 85 ALK, 33 ROS1, 20 RET fusions and 41 MET exon 14 skipping), this is one of the largest fusion-positive datasets ever tested. The results of the Idylla™ GeneFusion Assay were compared with earlier results of routine reference technologies including fluorescence in situ hybridization, immunohistochemistry, reverse-transcription polymerase chain reaction, and next-generation sequencing, establishing a high sensitivity/specificity of 96.1%/99.6% for ALK, 96.7%/99.0% for ROS1, 100%/99.3% for RET fusion, and 92.5%/99.6% for MET exon 14 skipping, and a low failure rate (0.9%). The Idylla™ GeneFusion Assay was found to be a reliable, sensitive, and specific tool for routine detection of ALK, ROS1, RET fusions and MET exon 14 skipping. Given its short turnaround time of about 3 h, it is a time-efficient upfront screening tool in FFPE samples, supporting rapid clinical decision making. Moreover, expression-imbalance-based detection of potentially novel fusions may be easily verified with other routine technologies without delaying treatment initiation.

Reticular Myxoid Odontogenic Neoplasm with Novel STRN::ALK Fusion: Report of 2 Cases in 3-Year-Old Males.

Odontogenic tumors represent a collection of entities ranging from hamartomas to destructive benign and malignant neoplasms. Occasionally, pathologists encounter gnathic lesions which clearly exhibit an odontogenic origin but do not fit within the confines of established diagnoses. Here, we describe two such odontogenic tumors, both affecting 3-year-old males. Each case presented as a destructive, radiolucent mandibular lesion composed of mesenchymal cells, some with unique multi-lobed nuclei, frequently arranged in a reticular pattern and supported by a myxoid stroma with focal laminations. Production of odontogenic hard tissues was also seen. Because of their unique microscopic features, both cases were investigated by next-generation sequencing and found to harbor the same STRN::ALK oncogene fusion. To our knowledge, these cases represent the first report of an odontogenic tumor with a STRN::ALK gene rearrangement. We propose the possibility that this neoplasm could be separate from other known odontogenic tumors. Both patients were treated with surgical resection and reconstruction. The prognosis of patients with this entity is currently uncertain but shall become more apparent over time as more cases are identified and followed.

Ciliated Muconodular Papillary Tumors of the Lung Harboring STRN::ALK Fusion: Case Report and Review of the Literature.

Ciliated muconodular papillary tumor (CMPT) is a rare pulmonary tumor, typically occurring in middle-aged and elderly individuals. The molecular mutation spectrum of CMPT remains insufficiently explored. Commonly known driver gene alterations include KRAS, BRAF, EGFR, and ALK rearrangement. This report details the clinicopathological features of 2 patients presenting with CMPT as pulmonary nodules during clinical examinations. Microscopic analysis revealed tumors with glandular or papillary structures, consisting of mucinous cells, ciliated columnar cells, and basal cells. Notably, both patients exhibited STRN::ALK fusion, a finding not previously associated with CMPT. STRN::ALK fusion serves as a target for therapy in various tumors, including non-small cell lung cancer, thyroid cancer, and colon cancer. Consequently, we conducted a review of relevant literature, summarizing the clinicopathological and molecular characteristics of CMPT to facilitate further research. Our insights enhance the understanding of this uncommon tumor and contribute to the expansion of its molecular alteration spectrum.

Drug Response of Patient-Derived Lung Cancer Cells Predicts Clinical Outcomes of Targeted Therapy.

Intratumor heterogeneity leads to different responses to targeted therapies, even within patients whose tumors harbor identical driver oncogenes. This study examined clinical outcomes according to a patient-derived cell (PDC)-based drug sensitivity test in lung cancer patients treated with targeted therapies. From 487 lung cancers, 397 PDCs were established with a success rate of 82%. In 139 PDCs from advanced non-small-cell lung cancer (NSCLC) patients receiving targeted therapies, the standardized area under the curve (AUC) values for the drugs was significantly correlated with their tumor response (p = 0.002). Among 59 chemo-naive EGFR/ALK-positive NSCLC patients, the PDC non-responders showed a significantly inferior response rate (RR) and progression-free survival (PFS) for the targeted drugs than the PDC responders (RR, 25% vs. 78%, p = 0.011; median PFS, 3.4 months [95% confidence interval (CI), 2.8-4.1] vs. 11.8 months [95% CI, 6.5-17.0], p < 0.001). Of 25 EGFR-positive NSCLC patients re-challenged with EGFR inhibitors, the PDC responder showed a higher RR than the PDC non-responder (42% vs. 15%). Four patients with wild-type EGFR or uncommon EGFR-mutant NSCLC were treated with EGFR inhibitors based on their favorable PDC response to EGFR inhibitors, and two patients showed dramatic responses. Therefore, the PDC-based drug sensitivity test results were significantly associated with clinical outcomes in patients with EGFR- or ALK-positive NSCLC. It may be helpful for predicting individual heterogenous clinical outcomes beyond genomic alterations.

Concordance of ALK fusion gene-rearrangement between immunohistochemistry and next-generation sequencing.

BACKGROUND: Although various companion diagnostic tests of ALK fusion gene-rearrangement are approved, few reports have assessed the concordance of ALK fusion gene-rearrangement in two companion diagnostic tests: next-generation sequencing (NGS) testing and immunohistochemistry (IHC). METHODS: The samples evaluated for gene alterations using NGS testing between May 2019 and November 2021 were included in this study. The inclusion criteria were as follows: samples were diagnosed with non-small cell lung cancer; the results of the NGS analysis were informative; and samples had residual specimens for IHC. We performed IHC on the residual specimens and retrospectively collected sample characteristics from medical records. RESULTS: A total of 185 samples were analyzed using NGS. Twenty-six samples were excluded because of failure to analyze gene alterations using NGS, no residual samples, and inadequate IHC. We analyzed 159 samples. The major histological type was adenocarcinoma (115 samples). The number of surgical and transbronchial lung biopsy specimens was 59 and 56, respectively. ALK fusion gene-rearrangement was detected in four samples using NGS, and five were detected using IHC. The sensitivity and specificity of IHC referred to by NGS were 75.0% and 98.7%, respectively. The concordance rate between IHC and NGS was 98.1%. ALK rearrangement was detected in two patients using IHC but not using NGS. In addition, ALK rearrangement was detected in one patient using NGS but not using IHC. CONCLUSION: Our results suggest that IHC and NGS might be complementary tests. In patients suspected of harboring ALK fusion gene-rearrangement, it should be analyzed using another diagnostic method.

Efficacy and safety of iruplinalkib (WX­0593) on non­small cell lung cancer with SPECC1L­ALK fusion: A case report.

The evidence of anaplastic lymphoma kinase (ALK) inhibitor for non-small cell lung cancer (NSCLC) harbouring sperm antigen with calponin homology and coiled-coil domains 1-like (SPECC1L)-ALK fusion was limited. In a previous case report, a Chinese, 44-year-old, female non-smoker with stage IV NSCLC harbouring SPECC1L-ALK fusion was treated with crizotinib ± bevacizumab for 23 months (from October 2017 to September 2019) and second-generation ALK inhibitor iruplinalkib for 2.5 months (from October 2019 to January 2020). The present study is an updated case report of subsequent follow-up of this patient. The patient participated in the phase II INTELLECT study and received iruplinalkib 180 mg once daily with a 7-day lead-in phase at 60 mg once daily. Systemic partial response was achieved 1 month later. Intracranial complete response was achieved nearly 5 months after iruplinalkib treatment initiation. Systemic and intracranial responses continued as of cut-off date (February 2023). The progression-free survival reached 39.3 months, with right censoring (progression did not occur during follow-up). Grade 3 hypertriglyceridaemia complicated with grade 2 hypercholesterolaemia recovered after fenofibrate treatment. The other adverse events were not noteworthy. Iruplinalkib demonstrated promising systemic and intracranial efficacy for NSCLC harbouring SPECC1L-ALK gene, with acceptable and manageable adverse events (for example, grade 3 hypertriglyceridaemia or grade 2 hypercholesterolaemia). Iruplinalkib may be an ideal option for patients with rare ALK fusions.

Detection of TRAF1-ALK fusion in skin lesions of systemic ALK+ anaplastic large cell lymphoma initially involving the skin and the draining lymph node.

A case of cytoplasmic anaplastic lymphoma kinase (ALK)-positive anaplastic large cell lymphoma (ALCL) initially involving the skin in a 44-year-old Japanese female is reported. The patient had a hemorrhagic erythematous tumor on the right thigh without any systemic symptoms. Pathology showed diffuse infiltration of CD30-positive anaplastic large cells positive for epithelial membrane antigen and cytoplasmic ALK. The right inguinal lymph node showed infiltration of tumor cells in the marginal sinus. Only 2 weeks after radiation therapy, the patient developed multiple subcutaneous nodules and lung involvement. Even after subsequent multichemotherapy sessions, cutaneous recurrence occurred. Literature review of cytoplasmic ALK-positive ALCL initially involving in the skin revealed that skin lesions were mostly seen in the extremities and that half of the cases developed extracutaneous lesions. Radiation and chemotherapy were effective for most cases. Inverse RT-PCR identified a tumor necrosis factor receptor-associated factor (TRAF)1-ALK fusion in our case. Most reported cases with this translocation experienced repeated changes in chemotherapy, suggesting poorer prognosis. Although ALK-positive ALCL generally responds well to chemotherapy, the presence of a TRAF1-ALK fusion may suggest resistance to treatment. Detection of fusion partners of ALK is important for predicting clinical courses and deciding treatment options.

Spontaneous Partial Regression of Fetal Lung Interstitial Tumor With A2M::ALK Rearrangement in a Neonate.

The differential diagnosis for neonatal primary lung masses includes developmental anomalies and congenital lung tumors. Fetal lung interstitial tumor (FLIT) is a rare benign mesenchymal lesion which presents either antenatally or within the first 3 months of age. FLIT is a circumscribed solid-cystic mass which histologically resembles the fetal lung during the canalicular stage at 20-24 weeks of gestation. It is composed of immature mesenchymal cells expanding the interstitium and irregular airspace-like structures. Of all published cases, only 1 identified an α2-macroglobulin (A2M)::anaplastic lymphoma kinase (ALK) fusion and all cases underwent surgical resection in the neonatal or infancy period. We present the second case of FLIT with an A2M::ALK fusion diagnosed postnatally in a neonate which partially regressed spontaneously during conservative management with interim resection at 39 months of age, and provide a review of the literature.

Melanoma in infants, caused by a gene fusion involving the anaplastic lymphoma kinase (ALK).

We describe the first cases of pediatric melanoma with ALK fusion gene arising within giant congenital melanocytic nevi. Two newborn boys presented with large pigmented nodular plaques and numerous smaller satellite nevi. Additional expansile nodules developed within both nevi and invasive melanomas were diagnosed before 10 months of age in both boys. Oncogenic driver mutations in NRAS and BRAF were absent in both cases. Instead, oncogenic ZEB2::ALK fusion genes were identified in both the nevus and melanoma developing within the nevus. In both cases, tumors were noted by ultrasound in utero, demonstrated significant nodularity at birth, and progressed to melanoma in the first year of life suggesting that congenital nevi with ALK fusion genes may behave more aggressively than those with other mutations. As ALK kinase inhibitors are effective against a range of tumors with similar ALK fusion kinases, identifying ALK fusion genes in congenital melanocytic nevi may provide an opportunity for targeted therapy.

EML4-ALK fusion protein in Lung cancer cells enhances venous thrombogenicity through the pERK1/2-AP-1-tissue factor axis.

BACKGROUND: Accumulating evidence links the echinoderm microtubule-associated protein-like 4 (EML4)-anaplastic lymphoma kinase (ALK) rearrangement to venous thromboembolism (VTE) in non-small cell lung cancer (NSCLC) patients. However, the corresponding mechanisms remain unclear. METHOD: High-throughput sequencing analysis of H3122 human ALK-positive NSCLC cells treated with ALK inhibitor/ dimethyl sulfoxide (DMSO) was performed to identify coagulation-associated differential genes between EML4-ALK fusion protein inhibited cells and control cells. Sequentially, we confirmed its expression in NSCLC patients' tissues and in the plasma of a subcutaneous xenograft mouse model. An inferior vena cava (IVC) ligation model was used to assess clot formation potential. Additionally, pathways involved in tissue factor (TF) regulation were explored in ALK-positive cell lines H3122 and H2228. Statistical significance was determined by Student t-test and one-way ANOVA using SPSS. RESULTS: Sequencing analysis identified a significant downregulation of TF after inhibiting EML4-ALK fusion protein activity in H3122 cells. In clinical NSCLC cases, TF expression was increased especially in ALK-positive NSCLC tissues. Meanwhile, H3122 and H2228 with high TF expression exhibited shorter plasma clotting time and higher TF activity versus ALK-negative H1299 and A549 in cell culture supernatant. Mice bearing H2228 tumor showed a higher concentration of tumor-derived TF and TF activity in plasma and the highest adjusted IVC clot weights. Limiting EML4-ALK protein phosphorylation downregulated extracellular regulated protein kinases 1/2 (ERK1/2)-activating the protein-1(AP-1) signaling pathway and thus attenuated TF expression. CONCLUSION: EML4-ALK fusion protein may enhance venous thrombogenicity by regulating coagulation factor TF expression. There was potential involvement of the pERK1/2-AP-1 pathway in this process.

Mediastinal epithelioid inflammatory myofibroblastic sarcoma with the EML4-ALK fusion: A case report and literature review.

Epithelioid inflammatory myofibroblastic sarcoma (EIMS) is an aggressive subtype of inflammatory myofibroblastic tumour which rarely affects the chest cavity. We, for the first time, report a case of mediastinal EIMS with the EML4-ALK fusion. A young woman presented to our hospital with cough, chest tightness and shortness of breath. Computed tomography (CT) showed a mixed attenuation soft-tissue mass in the right middle and upper mediastinum. Negative results were obtained from bronchoscopy forceps biopsy and endobronchial ultrasound-guided transbronchial fine needle aspiration. CT-guided percutaneous biopsy was finally performed. However, due to the rapidly progressed EIMS that compressed the trachea and right main bronchus, the patient died of respiratory failure 1 day before diagnosis. EIMS progresses rapidly, and an early diagnosis is important. For mediastinal EIMS, CT-guided percutaneous biopsy may be useful. Next-generation sequencing of blood may be instructive to EIMS patients who are intolerant to invasive biopsy.