Comparison between one-stage and two-stage CT-guided localization of lung nodules with surgical resection: a single medical center experience.

BACKGROUND: This retrospective study aimed to compare the efficacy and safety of one-stage computed tomography (OSCT)- to that of two-stage computed tomography (TSCT)-guided localization for the surgical removal of small lung nodules. METHODS: We collected data from patients with ipsilateral pulmonary nodules who underwent localization before surgical removal at Veteran General Hospital Kaohsiung between October 2017 and January 2022. The patients were divided into the OSCT and TSCT groups. RESULTS: We found that OSCT significantly reduced the localization time and risky time compared to TSCT, and the success rate of localization and incidence of pneumothorax were similar in both groups. However, the time spent under general anesthesia was longer in the OSCT group than in the TSCT group. CONCLUSIONS: The OSCT-guided approach to localize pulmonary nodules in hybrid operation room is a safe and effective technique for the surgical removal of small lung nodules.

Suppression of Migration and Invasion by 4-Carbomethoxyl-10-Epigyrosanoldie E from the Cultured Soft Coral Sinularia sandensis through the MAPKs Pathway on Oral Cancer Cells.

The primary reason for cancer-related fatalities is metastasis. The compound 4-carbomethoxyl-10-epigyrosanoldie E, derived from the Sinularia sandensis soft coral species grown in cultures, exhibits properties that counteract inflammation. Moreover, it has been observed to trigger both apoptosis and autophagy within cancerous cells. This research focuses on examining the inhibitory impact of 4-carbomethoxyl-10-epigyrosanoldie E on the migration and invasion processes in Cal-27 and Ca9-22 oral cancer cell lines. To assess how this compound affects cell migration and invasion, the Boyden chamber assay was employed. Furthermore, Western blot analysis was utilized to explore the underlying molecular mechanisms. In a dose-dependent manner, 4-carbomethoxyl-10-epigyrosanoldie E notably decreased the levels of matrix metalloproteinase-2 (MMP-2) and MMP-9, along with urokinase-type plasminogen activator (uPA), in both Cal-27 and Ca9-22 cell lines. Conversely, it elevated the concentrations of tissue inhibitors of metalloproteinases-1 (TIMP-1) and TIMP-2. In addition, the treatment with this compound led to the inhibition of phosphorylation in extracellular signal-regulated kinase (ERK), p38, and c-Jun N-terminal kinase (JNK). It also curtailed the expression of several key proteins including focal adhesion kinase (FAK), protein kinase C (PKC), growth factor receptor-bound protein 2 (GRB2), Rac, Ras, Rho A, mitogen-activated protein kinase kinase kinase 3 (MEKK3), and mitogen-activated protein kinase kinase 7 (MKK7). Furthermore, the expression levels of IQ-domain GTPase-activating protein 1 (IQGAP1) and zonula occludens-1 (ZO-1) were significantly reduced by the compound. The ability of 4-carbomethoxyl-10-epigyrosanoldie E to inhibit the migration and invasion of Cal-27 and Ca9-22 oral cancer cells was observed to be dose dependent. This inhibitory effect is primarily attributed to the suppression of MMP-2 and MMP-9 expression, as well as the downregulation of the mitogen-activated protein kinase (MAPK) signaling pathway.

Comparison of the Outcomes between Systematic Lymph Node Dissection and Lobe-Specific Lymph Node Dissection for Stage I Non-small Cell Lung Cancer.

BACKGROUND: This study compares the surgical and long-term outcomes, including disease-free survival (DFS), overall survival (OS), and cancer-specific survival (CSS), between lobe-specific lymph node dissection (L-SND) and systematic lymph node dissection (SND) among patients with stage I non-small cell lung cancer (NSCLC). METHODS: In this retrospective study, 107 patients diagnosed with clinical stage I NSCLC undergoing video-assisted thoracic surgery lobectomy (exclusion of the right middle lobe) from January 2011 to December 2018 were enrolled. The patients were assigned to the L-SND (n = 28) and SND (n = 79) groups according to the procedure performed on them. Demographics, perioperative data, and surgical and long-term oncological outcomes were collected and compared between the L-SND and SND groups. RESULTS: The mean follow-duration was 60.6 months. The demographic data and surgical outcomes and long-term oncological outcomes were not significantly different between the two groups. The 5-year OS of the L-SND and SND groups was 82% and 84%, respectively. The 5-year DFS of the L-SND and SND groups was 70% and 65%, respectively. The 5-year CSS of the L-SND and SND groups was 80% and 86%, respectively. All the surgical and long-term outcomes were not statistically different between the two groups. CONCLUSION: L-SND showed comparable surgical and oncologic outcomes with SND for clinical stage I NSCLC. L-SND could be a treatment choice for stage I NSCLC.

Assessment of Early Growth Response 1 in Tumor Suppression of Esophageal Squamous Cell Carcinoma.

Background: Esophageal squamous cell carcinoma (ESCC) is associated with poor survival despite surgical resection, and its pathogenesis has been broadly investigated in the past decade. Early growth response 1 (EGR-1) could involve regulating tumor development in ESCC cells. Methods: An attempt was made to examine the molecular and cellular influence of EGR-1 in esophageal cancer cells by RNA extraction, real-time PCR (qRT-PCR), cell culture, small interfering RNA (siRNA) knockdown, western blot, migration assay, and cell viability assay. One hundred and forty-four samples of ESCC were collected from our hospital and analyzed. Significantly higher EGR-1 expression was noted in tumor-adjacent normal tissue compared with tumor lesions. Results: The univariate analysis showed no significant impacts of EGR-1 expression on patients' survival. However, after adjusting for the pathological stage, patients with EGR-1 expression > 68th percentile had lower risks of cancer-related death. Moreover, knockdown of EGR-1 significantly enhanced cell migration, invasion, and resistance to chemotherapeutic agents in two ESCC cell lines. Conclusions: EGR-1 plays a key role in tumor suppression involving tumor viability suppression and reflects the treatment effect of current chemotherapy for ESCC.

Next Generation Sequencing for Potential Regulated Genes and Micro-RNAs of Early Growth Response-1 in the Esophageal Squamous Cell Carcinoma.

Esophageal cancer has a poor prognosis due to its aggressiveness and low survival rate. In Ease Asia, esophageal squamous cell carcinoma (ESCC) outnumbers esophageal adenocarcinoma (EAC). The ESCC patients still have high mortality despite modern surgical resection and neoadjuvant treatment. Determining patient and outcome prognostic factors is critical in ESCC treatment. In esophageal cancer, early growth response-1 (Egr-1) is a tumor suppressor gene, but the mechanism and associated genes are unknown. The study utilizes RNA interference method, the platform of Next Generation Sequencing (NGS) and bioinformatics analysis to investigate the influences after the Egr-1 gene slicing on the ESCC cells. The heat maps of differentially expressed mRNA and microRNAs were analyzed using the algorithm, Burrows-Wheller Aligner. The study showed that the expression of 51 mRNA and 26 microRNAs have significant changes in ESCC cells after Egr-1 knockdown. The KEGG enrichment analysis linked Egr-1-regulated genes and microRNAs. Egr-1 interactions with these genes and microRNAs may be important in tumor progression. In conclusions, this study provided the transcriptome patterns and relating pathway analysis for Egr-1 knockdown in ESCC cells. The mRNA and microRNAs altered by Egr-1 gene silencing might provide key information in the treatment of ESCC.

Chlorogenic Acid Inhibition of Esophageal Squamous Cell Carcinoma Metastasis via EGFR/p-Akt/Snail Signaling Pathways.

BACKGROUND/AIM: Chlorogenic acid (CGA) is a polyphenol compound found in a variety of foods, including coffee, tea, cherries, and apples. It has been found by a number of studies to affect the viability of human cancer cells. No study has investigated its effect on esophageal squamous cell carcinoma (ESCC) metastasis or the molecular mechanism underlying its effect on this disease. MATERIALS AND METHODS: We first used the Taiwanese ESCC cell line CE81T/VGH to create CE81T-M4 cells. Treatment of higher motility cells with chlorogenic acid for 24 h led to inhibition of cell migration and invasion as shown by scratch migration and transwell assays. RESULTS: Western blotting showed that chlorogenic acid halted the activation of EGFR/p-Akt/Snail pathway and suppressed the expression of MMP-2 and MMP-9. Knockdown of either EGFR or Akt inhibited Snail, MMP2, and MMP9 activity as well as cell migration and invasion. CONCLUSION: Chlorogenic acid inhibited cancer cell motility via the EGFR/p-Akt/Snail pathway and could potentially be used to develop an antimetastatic agent for ESCC in the future.

Does size affect the prognosis of resectable thymoma beyond the eighth edition TNM?

BACKGROUND: Thymoma is a type of rare mediastinal tumor whose clinical characteristics and indicators of prognosis are poorly understood. This single-institution retrospective study aimed to assess the predictive value of tumor, node, metastasis (TNM) staging incorporating tumor size in predicting the risk of thymoma recurrence after resection. METHODS: Four binary logistic regression models were developed. Models I and II included median tumor size and TNM stage, respectively. Model III included the above two variables. Model IV was model III containing these two variables and their interaction terms. All models were adjusted for WHO histological type, operational time, and adjuvant therapy. RESULTS: A total of 276 patients with a median age of 51.0, including 21 patients with thymoma recurrence, were included in this study. Models II or III showed a lower -2LogL and higher AUC (0.735 and 0.738 vs. 0.576) with significantly better discrimination than model I, and model III and model II shared similar discrimination. In model III, TNM stage was positively correlated with thymoma recurrence. The recurrence risk of patients with TNM stage IV was significantly higher than those with TNM stage I (OR of 11.03, p = 0.022). No significant correlation between the tumor size and recurrence risk (p = 0.779) and no interaction was found between medium tumor size and TNM stage in model IV. CONCLUSIONS: This study suggests that the prediction contribution of the TNM stage combined with tumor size is similar to the TNM stage alone for tumor recurrence in patients with thymoma after surgical resection.

Flaccidoxide Induces Apoptosis Through Down-regulation of PI3K/AKT/mTOR/p70S6K Signaling in Human Bladder Cancer Cells.

BACKGROUND/AIM: Urothelial carcinoma (UC) is the most common type of genitourinary cancer with high incidence and mortality rates in men. In this study, we used the BFTC-905 and T24 bladder cancer cell lines as in vitro models to investigate the pathways involved in flaccidoxide-induced apoptosis. MATERIALS AND METHODS: We utilized MTT assays, colony assays, wound-healing assays and fluorescence with TUNEL to confirm the cytotoxicity of flaccidoxide in bladder cancer cell lines. Potential proliferative and apoptotic molecular mechanisms were evaluated by western blotting. RESULTS: The expression of anti-apoptotic proteins Bcl-2 and phosphorylated Bad (p-Bad) was attenuated with an increasing flaccidoxide concentration, while the expression of proapoptotic proteins Bax, Bad, cleaved caspase-3, cleaved caspase-9 and cleaved PARP-1 was found increased. Additionally, phosphorylation of phosphoinositide 3-kinases (PI3K), protein kinase B (AKT) and mammalian target of rapamycin (mTOR) in the PI3K/AKT/mTOR pathway was reduced, leading to a reduction in the phosphorylation of downstream 70-kDa ribosomal protein S6 kinase 1 (p70S6K), S6 ribosomal protein (S6) and eukaryotic translation initiation factor 4B (eIF4B). However, eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1) protein phosphorylation was increased due to attenuation of the upstream phosphorylation of mTOR protein. CONCLUSION: Flaccidoxide-induced apoptosis in BFTC-905 and T24 cells is mediated by mitochondrial dysfunction and down-regulation the PI3K/AKT/mTOR/p70S6K signaling pathway.

Involvement of Mitochondrial Dysfunction, Endoplasmic Reticulum Stress, and the PI3K/AKT/mTOR Pathway in Nobiletin-Induced Apoptosis of Human Bladder Cancer Cells.

Nobiletin (NOB) is a polymethoxylated flavonoid isolated from citrus fruit peel that has been shown to possess anti-tumor, antithrombotic, antifungal, anti-inflammatory and anti-atherosclerotic activities. The main purpose of this study was to explore the potential of using NOB to induce apoptosis in human bladder cancer cells and study the underlying mechanism. Using an MTT assay, agarose gel electrophoresis, a wound-healing assay, flow cytometry, and western blot analysis, this study investigated the signaling pathways involved in NOB-induced apoptosis in BFTC human bladder cancer cells. Our results showed that NOB at concentrations of 60, 80, and 100 µM inhibited cell growth by 42%, 62%, and 80%, respectively. Cells treated with 60 µM NOB demonstrated increased DNA fragmentation, and flow cytometry analysis confirmed that the treatment caused late apoptotic cell death. Western blot analysis showed that mitochondrial dysfunction occurred in NOB-treated BFTC cells, leading to cytochrome C release into cytosol, activation of pro-apoptotic proteins (caspase-3, caspase-9, Bad, and Bax), and inhibition of anti-apoptotic proteins (Mcl-1, Bcl-xl, and Bcl-2). NOB-induced apoptosis was also mediated by regulating endoplasmic reticulum stress via the PERK/elF2α/ATF4/CHOP pathway, and downregulating the PI3K/AKT/mTOR pathway. Our results suggested that the cytotoxic and apoptotic effects of NOB on bladder cancer cells are associated with endoplasmic reticulum stress and mitochondrial dysfunction.

Kinome-Wide Screening with Small Interfering RNA Identified Polo-like Kinase 1 as a Key Regulator of Proliferation in Oral Cancer Cells.

Oral squamous cell carcinoma (OSCC) is one of the major leading causes of cancer-related death worldwide, with limited effective markers for diagnosis and therapy, which has caused a low overall survival rate in the past decades. Kinases play important roles in tumor development and malignancy in various types of cancer. However, little is known about the role of kinases in OSCC cells. In this study, an arrayed kinome small interfering RNA (siRNA) library was used to screen oral cancer cell lines and counter assayed with normal fibroblast cells to identify the genes required for cancer cell proliferation. We found that polo-like kinase 1 (PLK1) was one of the most potent genes required for OSCC cell proliferation. The knockdown of PLK1 with a siRNA or antisense oligonucleotide (ASO) consistently diminished cyclin-B1 (CCNB1) expression/phosphorylation and the G2-M phase transition. Similar effects were observed in cells treated with the PLK1 kinase inhibitor BI6727. Besides, The Cancer Genome Atlas (TCGA) analysis revealed that PLK1 was elevated in tumor tissues and associated with short survival in patients with OSCC. We also found that PLK1 expression was highly correlated with the expression of its downstream effector, CCNB1, in patients with OSCC. Coexpression of the two genes resulted in a poor prognosis of OSCC patients, particularly those in the advanced stages of OSCC. Taken together, our results suggest that PLK1 might be a diagnostic or therapeutic marker for OSCC.

The MAP3K7-mTOR Axis Promotes the Proliferation and Malignancy of Hepatocellular Carcinoma Cells.

Targeted therapy is currently limited for patients with hepatocellular carcinoma (HCC) due to the lack of suitable targets. Kinases play pivotal roles in many cellular biological processes, whereas dysregulation of kinases may lead to various diseases, particularly cancer. However, the role of kinases in HCC malignancy remains unclear. In this study, we employed a kinome small interfering RNA (siRNA) library, comprising 710 kinase-related genes, to screen whether any kinases were essential for cell proliferation in various HCC cell lines. Through a kinome siRNA library screening, we found that MAP3K7 was a crucial gene for HCC cell proliferation. Pharmacological or genetic ablation of MAP3K7 diminished the growth, migration, and invasion of HCC cells, including primary HCC cells. Stable knockdown of MAP3K7 attenuated tumor formation in a spheroid cell culture model and tumor xenograft mouse model. In addition, silencing MAP3K7 reduced the phosphorylation and expression of mammalian target of rapamycin (mTOR) in HCC cells. MAP3K7 expression was positively correlated with mTOR expression in tumors of patients with HCC. Higher co-expression of MAP3K7 and mTOR was significantly associated with poor prognosis of HCC. Taken together, our results revealed that the MAP3K7-mTOR axis might promote tumorigenesis and malignancy, which provides a potential marker or therapeutic target for HCC patients.

Bronchoscopic cryosurgery for metastatic tumor causing central airway obstruction: A case report.

RATIONALE: Bronchoscopic cryotherapy has been considered as one of the optional interventions for unresectable malignant central airway obstruction (CAO). And it provides high safety and effectiveness in airway patency re-establishment. This report describes the interventional bronchoscopic cryotherapy for a patient with CAO caused by squamous cell carcinoma of the esophagus. We display a series of dramatic change of chest radiographs before and after the intervention. PATIENT CONCERNS: A 70-year-old man with squamous cell carcinoma of the middle third of the esophagus (initial staging, pT2N0M0; stage IIB; in January 2017) underwent Video-assisted esophagectomy and reconstruction with a gastric conduit via a substernal route. Following Chest computed tomography and positron emission tomography revealed disease progression with paratracheal metastases. Progressive dyspnea and chest pain lasted for a month, and he was admitted to the ER. DIAGNOSES: Blood gas analysis revealed type I respiratory failure (pH, 7.445; PaO2, 69.4 mmHg; PaCO2, 40.6 mmHg). Other laboratory data were grossly normal. Chest radiography revealed a total left lung collapse. Chest CT identified a tumor blocking the left mainstem bronchus with the consolidation of the left lung. INTERVENTIONS: Dexamethasone and epinephrine inhalation were administered for initial symptom relief. Bronchoscopy performed 4 days after admission revealed a huge tumor completely occluding the left mainstem bronchus orifice. The occlusion was completely resolved following cryotherapy. Then, the first course of palliative chemotherapy with cisplatin plus fluorouracil, followed by the second course a month later, was administered. OUTCOMES: The latest chest radiograph showed a patent airway. The patient's condition remained stable for at least the following 2 months. LESSONS: Malignant CAO is a rare but potentially life-threatening condition. Several acceptable bronchoscopy techniques exist for treatment. Cryotherapy has high safety and effectiveness in airway patency re-establishment.

A rare presentation of pleomorphic carcinoma of lung mimic empyema.

Pleomorphic carcinoma (PC) of lung, a rare malignant lung tumor, is predominated in male smokers with over 65 years of age. The clinical presentations of PC are various including chest pain, cough, and dyspnea and so on. Asymptomatic patients have been also reported. In our case, a female non-smoker with middle age, who initially developed symptoms like empyema was diagnosed advanced PC. Poor progression occurred in this patient within one month from diagnosis to expiration. The lesson from this case is that malignancy of lung such as PC could not be excluded if a patient develops unmanageable empyema.

A new application for argon beam coagulation: the thymoma patient with pleural recurrence.

Thymomas are enigmatic tumors for which surgical resection is the mainstay of treatment. However, there are still many debates about resected thymomas with pleural recurrence. Repetitive operations for thymomas involving pleural recurrence are still the treatment of choice. Herein, we present a case with a suitable performance status for re-operation with a new application for argon beam coagulation. Both our experience and the currently available evidence suggest that surgical resection could be considered for patients with advanced thymomas, even for patients with locally advanced or Masaoka-Koga stage IV thymomas. Multimodality or multimodal, treatments resulted in better oncological outcomes for these patients. In this case, we proved that the new application of argon beam coagulation for a thymoma patient with pleural recurrence is safe and feasible. Additional evidence should be collected, and patients should be followed to assess long-term benefits.

Drug Repurposing Screening Identifies Tioconazole as an ATG4 Inhibitor that Suppresses Autophagy and Sensitizes Cancer Cells to Chemotherapy.

Background: Tumor cells require proficient autophagy to meet high metabolic demands and resist chemotherapy, which suggests that reducing autophagic flux might be an attractive route for cancer therapy. However, this theory in clinical cancer research remains controversial due to the limited number of drugs that specifically inhibit autophagy-related (ATG) proteins. Methods: We screened FDA-approved drugs using a novel platform that integrates computational docking and simulations as well as biochemical and cellular reporter assays to identify potential drugs that inhibit autophagy-required cysteine proteases of the ATG4 family. The effects of ATG4 inhibitors on autophagy and tumor suppression were examined using cell culture and a tumor xenograft mouse model. Results: Tioconazole was found to inhibit activities of ATG4A and ATG4B with an IC50 of 1.3 µM and 1.8 µM, respectively. Further studies based on docking and molecular dynamics (MD) simulations supported that tioconazole can stably occupy the active site of ATG4 in its open form and transiently interact with the allosteric regulation site in LC3, which explained the experimentally observed obstruction of substrate binding and reduced autophagic flux in cells in the presence of tioconazole. Moreover, tioconazole diminished tumor cell viability and sensitized cancer cells to autophagy-inducing conditions, including starvation and treatment with chemotherapeutic agents. Conclusion: Tioconazole inhibited ATG4 and autophagy to enhance chemotherapeutic drug-induced cytotoxicity in cancer cell culture and tumor xenografts. These results suggest that the antifungal drug tioconazole might be repositioned as an anticancer drug or chemosensitizer.

Correction: Long term oncological outcome of thymoma and thymic carcinoma - an analysis of 235 cases from a single institution.

[This corrects the article DOI: 10.1371/journal.pone.0179527.].

Long term oncological outcome of thymoma and thymic carcinoma - an analysis of 235 cases from a single institution.

BACKGROUND AND OBJECTIVES: Thymoma has a variable long-term oncological outcome after surgical resection. Survival and tumor recurrence were analyzed to determine the predisposing factors for tumor recurrence. METHODS: A total of 235 patients who underwent surgery for thymoma or thymic carcinoma from December 1997 to March 2013 were analyzed using Masaoka staging system and World Health Organization (WHO) histological classification. Surgical intervention included extended thymothymectomy via median sternotomy and thymomectomy via thoracotomy/ video-assisted thoracoscopic surgery (VATS). RESULTS: The median duration of follow-up was 105 months (12-198 months). Among these 235 patients, recurrence was observed in 25 patients (10.7%). according to Masaoka stage I, IIA, IIB, III, IVA, IVB, recurrence rates were 1/65(1.5%), 8/106(7.5%), 1/32(3.1%), 6/20(30.0%), 8/10(80.0%), 1/1(100.0%), respectively. Disease or treatment-related mortality was observed in 13 patients. Overall survival rate was 94.4%. After univariate analysis, predisposing factors for tumor recurrence included Masaoka stage, WHO histologic type, tumor size, adjuvant therapy and margin status. CONCLUSIONS: Due to the indolent behavior of thymoma, tumor recurrence appears to be a better assessment of oncological outcome rather than survival. Factors associated with tumor recurrence include Masaoka stage, WHO histologic type, tumor size, adjuvant therapy and margin status.

Dumbbell-Mimicked Mediastinal Angiomatosis.

Angiomatosis is a nonneoplastic proliferative vascular lesion, which occurs mostly in diverse soft tissues. We observed a rare case of mediastinal angiomatosis with intraspinal invasion that mimicked a dumbbell tumor in a 63-year-old man with a history of prostate adenocarcinoma. A roentgenogram of the chest showed that the patient had left pleural effusion and a left paraspinal mass, computed tomography disclosed a low-density fusiform lesion over the left paraspinal region, and magnetic resonance imaging confirmed a large posterior mediastinal tumor with T4 intraspinal invasion. The tumor was completely excised through a laminectomy of the T3-5 spine, followed by thoracoscopic removal of the mediastinal part. The definitive diagnosis was angiomatosis. Surgical removal of such a dumbbell-mimicked tumor is mandatory because it may progress to spinal cord compression.

Qualification and Verification of Serological Biomarker Candidates for Lung Adenocarcinoma by Targeted Mass Spectrometry.

Lung cancer is the leading cause of cancer mortality worldwide. Although many biomarkers have been identified for lung cancer, their low specificity and sensitivity present an urgent need for the identification of more candidate biomarkers. In this study, we conducted MRM-based targeted analysis to evaluate the potential utility of a list of candidate proteins for lung cancer diagnosis. A total of 1249 transitions of 420 peptides representing 102 candidate proteins from our previous study and the literature were first screened by MRM analysis in pooled plasma samples, resulting in 78 proteins remaining in the list. Relative quantification of these 78 proteins was further performed in 60 individual plasma samples from lung adenocarcinoma patients in stages I-III and matched healthy control subjects. Ultimately, nine proteins were found to be able to distinguish patients from controls. Further combinations of five, three, and two candidate marker proteins improved the sensitivity to discriminate patients from controls and resulted in a merged AUC value of nearly 1.00 in stages I-III patients versus controls. Our results highlighted several possible markers for lung adenocarcinoma, and the proposed protein panels require further validation in a larger cohort to evaluate their potential use in clinical applications or development of therapeutics.

Alpha-actinin 4 is associated with cancer cell motility and is a potential biomarker in non-small cell lung cancer.

BACKGROUND: Differential expression and secretion of alpha-actinin 4 (ACTN4) in the lung cancer cell lines CL1-0 and CL1-5 have been reported in previous proteomic studies. The aim of this study is to investigate the functional properties of the ACTN4 protein in non-small-cell lung cancer (NSCLC) cells and evaluate its clinical importance. METHODS: We used RNA interference to knock down and overexpress ACTN4 protein to evaluate the effects of this intervention on cancer cell invasion and migration, as well as on microscopic cellular morphology. Furthermore, we examined by immunohistochemistry the expression of ACTN4 protein in tissue samples at different stages of lung cancer and compared the protein levels of ACTN4 in blood plasma samples from patients with histologically confirmed lung cancer and healthy controls. RESULTS: CL1-5 cell motility was significantly suppressed by the knockdown of ACTN4 protein. The morphology of CL1-5 cells changed from a predominantly mesenchymal-like shape into a globular shape in response to ACTN4 protein knockdown. A quantitative immunohistochemical assessment of lung cancer tissues revealed that ACTN4 protein level was considerably higher in cancerous tissues than in the adjacent normal ones, and the area under the receiver operating characteristic curve was 0.736 (p < 0.001). According to an enzyme-linked immunosorbent assay, the plasma levels of ACTN4 protein were significantly different between cancer patients and healthy controls, and the areas under the receiver operating characteristic curves were 0.828 and 0.909, respectively, for two independent cohorts (p < 0.001). CONCLUSIONS: We demonstrate that the knockdown of ACTN4 protein inhibited cell invasion and migration. These results suggest that ACTN4 is associated with lung cancer cell motility. Thus, the level of ACTN4 in cancerous tissue and plasma is related to the presence of lung cancer.