Distribution and prognostic impact of EGFR and KRAS mutations according to histological subtype and tumor invasion status in pTis-3N0M0 lung adenocarcinoma.

BACKGROUND: The prognostic impact of EGFR mutation as major targetable somatic gene variant on lung adenocarcinoma is controversial. KRAS is another major somatic variant in lung adenocarcinoma, and a therapeutic agent for KRAS G12C became available in clinical settings. These mutations represent clinicopathological features of lung adenocarcinoma and can guide the treatment choice after recurrence. We evaluated the prognostic impact of EGFR and KRAS mutations by considering other clinicopathological recurrence risks in resected pTis-3N0M0 lung adenocarcinoma. METHODS: Clinicopathological features related to recurrence and genetic status were estimated in consecutive 877 resected cases. Recurrence-free survival (RFS), cumulative recurrence rate (CRR), and overall survival (OS) were compared. Uni- and multivariate analyses for RFS were performed after excluding cases with little or no recurrence risks. RESULTS: EGFR mutation was more likely to be harbored in female, never-smoker, or patients accompanied by > 5% lepidic component. KRAS mutation was more likely to be harbored in patients with current/ex-smoking history, International Association for the Study of Lung Cancer (IASLC) grade 3, or accompanied lymphatic or vascular invasion. In IASLC grade 2 and 3 patients, EGFR or KRAS mutation cases had significantly worse 5-year RFS than wild type patients (76.9% vs. 85.0%, hazard ratio [HR] = 1.55, 95% confidence interval [CI] = 1.62-6.41, P < 0.001). EGFR or KRAS mutation cases had significantly higher 5-year CRR than wild type patients (17.7% vs. 9.8%, HR = 1.69, 95% CI = 1.44-6.59, P = 0.0038). KRAS mutation cases had higher 5-year CRR than EGFR mutation cases (16.7% vs. 21.4%, HR = 1.62, 95% CI = 0.96-7.19, P = 0.061). There was no significant difference in OS between cohorts. Multivariate analysis revealed that a positive EGFR/KRAS mutation status was risk factor for worse RFS (HR = 2.007, 95% CI = 1.265-3.183, P = 0.003). CONCLUSION: Positive EGFR and KRAS mutation statuses were risk factors for recurrence in resected IASLC grade 2 and 3 patients. KRAS mutations were more likely to be confirmed in cases with an increased risk of recurrence. EGFR and KRAS mutation statuses should be evaluated simultaneously when assessing the risk of recurrence.

miR-142-3p Suppresses Invasion and Adhesion of Mesothelioma Cells by Downregulating ITGAV.

INTRODUCTION: Malignant mesothelioma is an aggressive cancer associated with asbestos exposure. Currently, the efficacy of therapeutics is limited in malignant mesothelioma, and developing more effective therapies is the need of the hour. Non-coding RNAs (ncRNAs), including microRNAs (miRNAs), have attracted attention as therapeutic targets. To explore potential therapeutic targets, we focused on miR-142-3p expression, which was found to be significantly downregulated in mesothelioma cell lines in our previous study. METHODS: Mesothelioma cell lines and tissues were validated for expression of miR-142-3p or integrin subunit alpha-V (ITGAV). We transfected mesothelioma cell lines with miR-142-3p mimic and ITGAV siRNA and analyzed their biological functions. RESULTS: We found that miR-142-3p was significantly downregulated in mesothelioma tissues. Transfection with miR-142-3p mimic significantly suppressed cell proliferation, migration, and invasion. Bioinformatics analysis of potential targets of miR-142-3p identified ITGAV. Membrane ITGAV expression in mesothelioma cell lines was confirmed using immunocytochemistry. ITGAV was significantly upregulated in mesothelioma tissues. Moreover, transfection of miR-142-3p mimics into mesothelioma cell lines significantly suppressed ITGAV expression, indicating that miR-142-3p targets ITGAV. Next, ITGAV siRNA transfection into mesothelioma cell lines inhibited cell proliferation, migration, and invasion. Further investigation of cell adhesion mechanisms showed that the miR-142-3p/ITGAV axis specifically affects mesothelioma cell adhesion via vitronectin in the extracellular matrix. CONCLUSION: This study proposed that the miR-142-3p/ITGAV axis is involved in tumor progression in malignant mesothelioma.

Challenges and limitation of MTAP immunohistochemistry in diagnosing desmoplastic mesothelioma/sarcomatoid pleural mesothelioma with desmoplastic features.

AIM: Genomic-based ancillary assays including immunohistochemistry (IHC) for BRCA-1 associated protein-1 (BAP1) and methylthioadenosine phosphorylase (MTAP), and fluorescence in situ hybridization (FISH) for CDKN2A are effective for differentiating pleural mesothelioma (PM) from reactive mesothelial proliferations. We previously reported a combination of MTAP and BAP1 IHC effectively distinguishes sarcomatoid PM from fibrous pleuritis (FP). Nevertheless, cases of sarcomatoid PM with desmoplastic features (desmoPM) are encountered where the IHC assessment is unclear. METHODS AND RESULTS: We evaluated assessment of MTAP IHC, BAP1 IHC, and CDKN2A FISH in 20 desmoPM compared to 24 FP. MTAP and BAP1 IHC could not be assessed in 11 (55 %) and 10 (50 %) cases, respectively, due to loss or faint immunoreactivity of internal positive control cells, while CDKN2A FISH could be evaluated in all cases. The sensitivities for MTAP loss, BAP1 loss, and CDKN2A homozygous deletion in desmoPM were 40 %, 10 %, and 100 %. A combination of MTAP loss and BAP1 loss yielded 45 % of sensitivity. CONCLUSIONS: MTAP IHC is a useful surrogate diagnostic marker in differentiating ordinary sarcomatoid PM from FP, but its effectiveness is limited in desmoPM. CDKN2A FISH is the most effective diagnostic assays with 100 % sensitivity and specificity in discriminating desmoPM from FP in the facilities where the FISH assay is available.

Serum S100 calcium-binding protein A4 as a novel predictive marker of acute exacerbation of interstitial pneumonia after surgery for lung cancer.

BACKGROUND: Acute exacerbation (AE) of interstitial pneumonia (IP) is the most fatal complication after lung resection for lung cancer. To improve the prognosis of lung cancer with IP, the risk factors of AE of IP after lung resection should be assessed. S100 calcium-binding protein A4 (S100A4) is a member of the S100 family of proteins and is a known marker of tissue fibrosis. We examined the usefulness of S100A4 in predicting AE of IP after lung resection for lung cancer. METHODS: This study included 162 patients with IP findings on preoperative high-resolution computed tomography scan who underwent curative-intent lung resection for primary lung cancer between April 2007 and March 2019. Serum samples were collected preoperatively. Resected lung tissue from 76 patients exhibited usual IP (UIP) pattern in resected lung were performed immunohistochemistry (IHC). Relationship between S100A4 and the incidence of AE of IP and short-term mortality was analyzed. RESULTS: The receiver operating characteristic area under the curve for serum S100A4 to predict postoperative AE of IP was 0.871 (95% confidence interval [CI], 0.799-0.943; P < 0.001), with a sensitivity of 93.8% and a specificity of 75.3% at the cutoff value of 17.13 ng/mL. Multivariable analysis revealed that a high serum S100A4 level (> 17.13 ng/mL) was a significant risk factor for AE of IP (odds ratio, 42.28; 95% CI, 3.98-449.29; P = 0.002). A 1-year overall survival (OS) was significantly shorter in patients with high serum levels of S100A4 (75.3%) than in those with low serum levels (92.3%; P = 0.003). IHC staining revealed that fibroblasts, lymphocytes, and macrophages expressed S100A4 in the UIP area, and the stroma and fibrosis in the primary tumor expressed S100A4, whereas tumor cells did not. CONCLUSIONS: Serum S100A4 had a high predictive value for postoperative AE of IP and short-term mortality after lung resection.

[An Autopsy Case of IGF‒⠡ Secreting Gastric Cancer with Non‒Islet Cell Tumor Hypoglycemia].

We present the case of a 72‒year‒old male patient with anorexia who was diagnosed with advanced gastric cancer with multiple liver metastasis. He had marked hypoglycemia and lightheadedness from the time of admission. The serum insulin level was very low and other endocrinology test results were normal. He was finally diagnosed with non‒islet cell tumor hypoglycemia(NICTH)based on IHC findings that tumor cells expressed insulin‒like growth factor (IGF)Ⅱ. After the patient received intravenous glucocorticoid therapy along with S‒1 plus CDDP combination chemotherapy, the hypoglycemia was quickly resolved. However, he developed septic shock in reaction to the chemotherapy and died on the 35th day of hospitalization. The autopsy showed the presence of IGF‒Ⅱ in the liver metastasis, as well as in the primary tumor.

Intense Expression of EGFR L858R Characterizes the Micropapillary Component and L858R Is Associated with the Risk of Recurrence in pN0M0 Lung Adenocarcinoma with the Micropapillary Component.

BACKGROUND: Lung adenocarcinoma with the micropapillary (MP) component poses a higher risk of recurrence even when the MP component is not predominant. This study explored genetic features associated with highly malignant behavior of lung adenocarcinoma with the MP component. METHODS: The MP and papillary (PaP) components were captured separately in three patients. Comprehensive mRNA expressions of somatic variants were compared between the MP and PaP components of each patient using next-generation sequencing (NGS). The protein expression of the NGS-detected variant was validated by immunohistochemistry. The prognostic impact of the detected variant was evaluated in 288 adenocarcinoma patients with resection of pN0M0. RESULTS: In two cases, NGS suggested higher RNA expression of EGFR L858R in the MP component than in the PaP component (allele frequency, 0.485 vs. 0.155 and 1.000 vs. 0.526, respectively; P < 0.001 for both). Immunohistochemistry validated intense expression of L858R in the MP component of 27 MP-positive (MP+) patients. Among 288 pN0M0 patients, L858R was more frequently harbored in the MP+ patients than in the MP-negative (MP-) patients. The MP+ patients harboring L858R showed significantly worse recurrence-free survival (RFS) than the MP+ patients without L858R (median RFS 38.7 and 55.0 months, respectively; hazard ratio [HR] 3.004; 95% confidence interval [CI] 1.306-9.132; P = 0.012). Multivariate analysis of the MP+ patients showed that positive L858R status was associated with poorer RFS (HR 2.976; 95% CI 1.190-7.442; P = 0.020). CONCLUSIONS: EGFR L858R was more frequently harbored in the MP+ adenocarcinoma patients than in the MP- adenocarcinoma patients. Intense expression of L858R in the MP component was suggested, and the MP+ patients harboring L858R were at comparatively higher risk of recurrence in the group with pN0M0 lung adenocarcinoma.

Mucin 21 is a novel, negative immunohistochemical marker for epithelioid mesothelioma for its differentiation from lung adenocarcinoma.

AIMS: The process of differential diagnosis between epithelioid mesothelioma and lung adenocarcinoma has been progressing; however, there are no absolute immunohistochemical markers with which to definitively diagnose epithelioid mesothelioma. The aim of this study was to search for a novel negative marker of epithelioid mesothelioma. METHODS AND RESULTS: We immunohistochemically studied the applicability of mucin 21 (MUC21), which was identified in our previous study, as a novel, negative diagnostic marker for epithelioid mesothelioma. Seventy epithelioid mesotheliomas and 70 lung adenocarcinomas were investigated for the expression of MUC21, along with other previously reported markers, by the use of immunohistochemistry. MUC21 was expressed in only two of the 70 (3%) epithelioid mesotheliomas, as compared with 67 of the 70 (96%) lung adenocarcinomas. The sensitivity, specificity and accuracy of negative MUC21 expression for differentiating epithelioid mesothelioma from lung adenocarcinoma were 97%, 96%, and 96%, respectively; these are similar to those of carcinoembryonic antigen and claudin-4, and better than those of thyroid transcription factor-1, napsin-A, and mucin 4. CONCLUSION: MUC21 could be used as an additional, novel, negative immunohistochemical marker to differentiate mesothelioma from lung adenocarcinoma.

Glypican-1 immunohistochemistry is a novel marker to differentiate epithelioid mesothelioma from lung adenocarcinoma.

Histological morphology alone is not sufficient for the pathological diagnosis of malignant mesothelioma. Positive and negative immunohistochemical markers are necessary to differentiate it from lung adenocarcinoma. As calretinin and D2-40, the recognized positive markers of mesothelioma, are expressed in lung adenocarcinoma to some extent, novel markers with high specificity are desirable. In this study, we investigated the applicability of glypican-1 immunohistochemistry to differentiate epithelioid mesothelioma from lung adenocarcinoma. We investigated 82 cases of epithelioid mesothelioma and 97 cases of lung adenocarcinoma for glypican-1 expression by immunohistochemistry using a commercially available antibody. All 82 cases of epithelioid mesothelioma showed glypican-1 expression, most with diffuse and strong reactivity. In contrast, only three cases of lung adenocarcinoma showed focal glypican-1 expression. Glypican-1 expression showed 100 sensitivity, 97% specificity, and a 98% accuracy rate to differentiate epithelioid mesothelioma from lung adenocarcinoma. The sensitivity of glypican -1 immunohistochemistry is as high as that of calretinin and D2-40, and its specificity is far better than that of calretinin and D2-40. Therefore, we recommend including glypican -1 immunohistochemistry as a positive marker of epithelioid mesothelioma.

MUC4, a novel immunohistochemical marker identified by gene expression profiling, differentiates pleural sarcomatoid mesothelioma from lung sarcomatoid carcinoma.

Sarcomatoid mesothelioma, a histological subtype of malignant pleural mesothelioma, is a very aggressive tumor with a poor prognosis. Histological diagnosis of sarcomatoid mesothelioma largely depends on the histomorphological feature of spindled tumor cells with immunohistochemical reactivity to cytokeratins. Diagnosis also requires clinico-radiological and/or macroscopic evidence of an extrapulmonary location to differentiate it from lung sarcomatoid carcinoma. Although there are promising immunohistochemical antibody panels to differentiate mesothelioma from lung carcinoma, a consensus on the immunohistochemical markers that distinguish sarcomatoid mesothelioma from lung sarcomatoid carcinoma has not been reached and requires further study. We performed whole gene expression analysis of formalin-fixed paraffin-embedded tissue from sarcomatoid mesothelioma and lung sarcomatoid carcinoma and observed significant differences in the expression of MUC4 and other genes between sarcomatoid mesothelioma and lung sarcomatoid carcinoma. Immunohistochemistry demonstrated that MUC4 was expressed in the spindled tumor cells of lung sarcomatoid carcinoma (21/29, 72%) but was not expressed in any sarcomatoid mesothelioma (0/31, 0%). To differentiate sarcomatoid mesothelioma from lung sarcomatoid carcinoma, negative MUC4 expression showed 100% sensitivity and 72% specificity and accuracy rate of 87%, which is higher than immunohistochemical markers such as calretinin, D2-40 and Claudin-4. Therefore, we recommend to include MUC4 as a novel and useful negative immunohistochemical marker for differentiating sarcomatoid mesothelioma from lung sarcomatoid carcinoma.

Utility and pitfalls of immunohistochemistry in the differential diagnosis between epithelioid mesothelioma and poorly differentiated lung squamous cell carcinoma.

AIMS: The aims of this study were to clarify the usefulness of immunohistochemistry in the differential diagnosis of epithelioid mesothelioma with a solid growth pattern [solid epithelioid mesothelioma (SEM)] and poorly differentiated squamous cell carcinoma (PDSCC), and to confirm the validity of a specific type of antibody panel. Additionally, we aimed to clarify the pitfalls of immunohistochemical analyses. METHODS AND RESULTS: Formalin-fixed paraffin-embedded specimens from 36 cases of SEM and 38 cases of PDSCC were immunohistochemically examined for calretinin, podoplanin (D2-40), Wilms' tumour gene product (WT1), cytokeratin (CK) 5/6, p40, p63, carcinoembryonic antigen (CEA), epithelial-related antigen (MOC31), claudin-4, thyroid transcription factor-1 (TTF-1), and napsin A. WT1 showed the highest diagnostic accuracy (85.1%) as a mesothelial marker, and CEA, p40 and claudin-4 showed higher diagnostic accuracies (95.9%, 94.6%, and 93.2%, respectively) as carcinoma markers. Calretinin (diagnostic accuracy: 75.7%), D2-40 (diagnostic accuracy: 67.6%), CK5/6 (diagnostic accuracy: 63.5%), TTF-1 (diagnostic accuracy: 55.4%) and napsin A (diagnostic accuracy: 52.7%) could not differentiate between SEM and PDSCC. Among these markers, the combination of calretinin and WT1 showed the highest diagnostic accuracy (86.5%) as a positive marker, and the combination of p40 and CEA showed the highest diagnostic accuracy (97.3%) as a negative marker. The combination of CEA and claudin-4 also showed relatively high diagnostic accuracy (94.6%) as a negative marker. CONCLUSIONS: We recommend the combination of WT1 and calretinin as a positive maker, and the combination of CEA and claudin-4 as a negative marker, for differential diagnoses of SEM and PDSCC.

Use of Anti-Noxa Antibody for Differential Diagnosis between Epithelioid Mesothelioma and Reactive Mesothelial Hyperplasia.

OBJECTIVES: The histological differential diagnosis between epithelioid mesothelioma (EM) and reactive mesothelial hyperplasia (RMH) is not always straightforward. The aim of the present study was to search for new immunohistochemical markers to distinguish EM from RMH. METHODS: We evaluated and compared the expression of apoptosis-related genes in EM and RMH by real-time RT-PCR array analysis followed by clustering of significant gene expression. Immunohistochemical staining and statistical analysis of Noxa expression in 81 cases of EM and 55 cases of RMH were performed and compared with the utility of other previously reported antibodies such as Desmin, EMA, GLUT-1, IMP-3 and CD146. RESULTS: Noxa mRNA expression levels were found to be increased in EM when compared to RMH by RT-PCR array analysis. In the immunohistochemical analysis, Noxa showed sensitivity of 69.0%, specificity of 93.6% and positive predictive value of 93.0% as a positive marker of EM in distinguishing it from RMH, and these values were almost similar to IMP-3. CONCLUSION: Noxa is a marker with relatively high specificity, and can be used to distinguish EM from RMH. It would be a valuable addition to the current antibody panel used for the differential diagnosis of EM and RMH.

Prognostic significance of vascular invasion in intermediate-grade subtype of lung adenocarcinoma.

OBJECTIVES: Although the recent reclassification of histological subtypes of lung adenocarcinoma reflects disease prognosis better, the prognosis of papillary and acinar-predominant adenocarcinoma, which are highly prevalent, is heterogeneity. The present study aimed to identify the prognostic indicators for papillary and acinar-predominant adenocarcinoma. METHODS: This retrospective study included 315 consecutive patients with completely resected pathological N0 lung adenocarcinoma tumors ≤3 cm from two institutions. Tumors were classified according to histologically predominant subtypes as low-grade (adenocarcinoma in situ, minimally invasive adenocarcinoma or lepidic predominant), intermediate-grade (papillary or acinar predominant) or high-grade (solid or micropapillary predominant). Prognostic factors in intermediate-grade group were assessed among clinicopathological factors of age, gender, surgical procedure, tumor size, pleural, lymphatic and vascular invasion using Cox proportion hazards analyses. RESULTS: There were 174 patients in the low-grade group, 109 in the intermediate-grade group and 32 in the high-grade group. The 3-year recurrence-free survival rates were 98.1%, 86.3% and 74.8% for these groups, respectively (P < 0.001). In the intermediate-grade group, the presence of vascular invasion was an independent prognostic factor on multivariate Cox regression analysis of recurrence-free survival (hazard ratio, 3.48; 95% confidence interval, 1.26-9.57, P = 0.01). Classification of intermediate-grade group based on vascular invasion revealed a clear division into favorable and unfavorable prognostic subgroups. CONCLUSIONS: Consideration of the vascular invasion status in addition to the predominant subtype could provide a more accurate assessment of malignant aggressiveness and prognosis of patients with early-stage lung adenocarcinoma.

Association between [18F]-fluoro-2-deoxyglucose uptake and expressions of hypoxia-induced factor 1α and glucose transporter 1 in non-small cell lung cancer.

OBJECTIVE: High maximum standardized uptake values on [(18)F]-fluoro-2-deoxyglucose positron emission tomography are associated with inferior survival in non-small cell lung cancer. Here, we investigated the biological mechanisms underlying [(18)F]-fluoro-2-deoxyglucose uptake in non-small cell lung cancer. METHODS: This study included 133 patients with non-small cell lung cancer (109 with adenocarcinoma and 24 with squamous cell carcinoma). The patients underwent tumour resection, at the latest, 4 weeks after [(18)F]-fluoro-2-deoxyglucose positron emission tomography. The maximum standardized uptake values for primary lesions were calculated based on [(18)F]-fluoro-2-deoxyglucose uptake. The expression of hypoxia-inducible factor 1α and glucose transporter 1 was evaluated on immunostained tumour sections using six-point grading scales. RESULTS: Maximum standardized uptake values and the expression of hypoxia-inducible factor 1α and glucose transporter 1 were significantly higher in squamous cell carcinoma than in adenocarcinoma (P < 0.001, P = 0.034 and P < 0.001, respectively). In adenocarcinoma, but not squamous cell carcinoma, maximum standardized uptake values, hypoxia-inducible factor 1α and glucose transporter 1 correlated with various clinicopathological factors relating to malignancy, and maximum standardized uptake values and glucose transporter 1 were associated with disease-free survival (P < 0.001 and P = 0.029) and overall survival (P < 0.001 and P = 0.033, respectively). Patients with high expression of hypoxia-inducible factor 1α tended to exhibit shorter disease-free survival and overall survival than those with low expression, but the differences were not significant (P = 0.32 and P = 0.15, respectively). And then in adenocarcinoma, hypoxia-inducible factor 1α and glucose transporter 1, glucose transporter 1 and maximum standardized uptake values, and hypoxia-inducible factor 1α and maximum standardized uptake values were significantly correlated (P < 0.001 for all), suggesting that hypoxia-inducible factor 1α-induced glucose transporter 1 might influence maximum standardized uptake values on [(18)F]-fluoro-2-deoxyglucose positron emission tomography. CONCLUSIONS: In lung adenocarcinoma, but not squamous cell carcinoma, hypoxia-inducible factor 1α and glucose transporter 1 expressions indicate tumour aggressiveness pathologically and might explain high [(18)F]-fluoro-2-deoxyglucose uptake on positron emission tomography and correlate with poor prognosis.

SPARC Is a Novel Positive Immunohistochemical Marker of Epithelioid Mesothelioma to Differentiate It From Lung Adenocarcinoma and/or Squamous Cell Carcinoma.

Epithelioid mesothelioma with a solid histologic pattern (solid epithelioid mesothelioma) is difficult to distinguish from a poorly differentiated squamous cell lung carcinoma and/or solid lung adenocarcinoma. Thus, immunohistochemical markers are essential for diagnosis; however, the sensitivity and specificity of pre-existing mesothelial markers are suboptimal, particularly for differentiation from squamous cell carcinoma. Using a cancer-dependency map, we analyzed gene expression data of pleural mesothelioma and non-small cell lung cancer cell lines (squamous cell carcinoma and adenocarcinoma) and identified secreted protein acidic and cysteine-rich (SPARC) as a promising candidate for the differential diagnosis of epithelioid mesothelioma from lung squamous cell carcinoma and/or lung adenocarcinoma. SPARC expression in mesothelioma and lung cancer cell lines was validated using reverse-transcription polymerase chain reaction, western blotting, and immunohistochemistry. Immunohistochemical staining was performed using anti-SPARC antibodies against solid epithelioid mesothelioma, solid lung adenocarcinoma, and poorly differentiated lung squamous cell carcinoma. SPARC positivity was seen in 42/45 (93.3%) of solid epithelioid mesothelioma, 2/40 (5%) solid lung adenocarcinoma, and 2/45 (4.5%) of lung squamous cell carcinomas. The sensitivity, specificity, and diagnostic accuracy for differentiating solid epithelioid mesothelioma from lung cancer (solid lung adenocarcinoma and poorly differentiated lung squamous cell carcinoma) were 93.3, 95.2, and 94.6%, respectively. In conclusion, SPARC is a novel mesothelial marker that can be used to differentiate epithelioid mesothelioma from squamous cell carcinoma and lung adenocarcinoma.

FOXM1 Promotes Mesothelioma Cell Migration and Invasion via Activation of SMAD Signaling.

BACKGROUND/AIM: Forkhead box M1 (FOXM1) is a transcription factor closely associated with various human malignancies and is considered an attractive target for cancer therapy. Mesothelioma is a malignancy primarily due to asbestos exposure and certain genetic factors, requiring a better understanding of tumorigenesis for improved treatment. Asbestos-exposed human mesothelial cells have been reported to up-regulate FOXM1 expression in a dose-dependent manner. MATERIALS AND METHODS: FOXM1 expression was evaluated in mesothelioma tissues and cell lines. FOXM1 small interfering RNA was transfected into mesothelioma cell lines to analyze its biological functions and regulatory mechanisms. RESULTS: FOXM1 was over-expressed in mesothelioma tissues and cell lines. Knock-down of FOXM1 in mesothelioma cell lines inhibited cell proliferation, migration, and invasion. These results suggest that up-regulation of FOXM1 expression promotes mesothelioma tumorigenesis and progression. We previously reported that insulin-like growth factor 2 mRNA binding protein 3 (IGF2BP3) promotes the proliferation, migration, and invasion of mesothelioma cell lines. In this study, IGF2BP3 knock-down suppressed FOXM1 expression in mesothelioma cell lines. Our results suggest that IGF2BP3, an upstream regulator, contributes to increased FOXM1 expression. Furthermore, IGF2BP3 and FOXM1 knock-down suppressed SMAD signaling by inhibiting SMAD2/3 phosphorylation in mesothelioma cell lines. CONCLUSION: IGF2BP3/FOXM1 promotes mesothelioma cell migration and invasion via SMAD signaling, highlighting IGF2BP3/FOXM1 as a potential target for mesothelioma treatment.

Usefulness of serum S100A4 and positron-emission tomography on lung cancer accompanied by interstitial pneumonia.

BACKGROUND: The S100 calcium-binding protein A4 (S100A4) and the accumulation of [18F]-fluoro-2-deoxy-D-glucose (FDG) in noncancerous interstitial pneumonia (IP) area are predictors of postoperative acute exacerbation (AE) of IP after pulmonary resection for lung cancer with IP. However, the significance of combining these markers for predicting short-term outcome and long-term prognosis is not known. METHODS: Patients diagnosed with IP on preoperative high-resolution computed tomography and who had undergone pulmonary resection for primary lung cancer between April 2010 and March 2019 at Hiroshima University were included in this study. Predictive factors for the cumulative incidence of death from other than lung cancer (CIDOL) were investigated using the Fine and Gray model. CIDOL, perioperative outcome, and cumulative incidence of all death (CIAD) were retrospectively compared based on serum S100A4 and FDG accumulation. RESULTS: A total of 121 patients were included in this study. High S100A4 (hazard ratio [HR], 2.541; p = 0.006) and FDG accumulation (HR, 3.199; p = 0.038) were significant predictors of CIDOL. AE of IP occurred only in patients with high S100A4/FDG (+). CIDOL of patients with high S100A4/FDG (+) was higher than those with high S100A4/FDG (-) or low S100A4/FDG (+) (p < 0.001), and CIAD of patients with high S100A4/FDG (+) was also higher than those with high S100A4/FDG (-) or low S100A4/FDG (+) patients (p = 0.021). CONCLUSIONS: Serum S100A4 and FDG accumulation in the noncancerous IP area were significant predictors of CIDOL after lung resection for lung cancer with IP and may help decide the treatment strategy.

Musashi-1 Is a Novel Immunohistochemical Marker of Neuroendocrine Carcinoma of the Lung.

Small cell lung cancer (SCLC) and large cell neuroendocrine carcinoma (LCNEC) have recently been grouped as lung neuroendocrine carcinomas (NECs). Because these lung NECs are clinically malignant and their treatment strategies differ from those of non-SCLC, the quality of diagnosis has a significant prognostic impact. The diagnosis of LCNEC requires positive immunohistochemical staining with chromogranin A, synaptophysin, and CD56, along with a morphological diagnosis, and insulinoma-associated protein 1 (INSM1) has been proposed as an additional marker but is still not an ideal or better marker. We investigated Musashi-1 as a novel immunohistochemical marker in 42 patients with SCLCs and 44 with LCNECs who underwent lung resection between 1998 and 2020 at our institution. We found Musashi-1 expression in 98% (41/42) SCLC and in 90% (40/44) LCNEC. These findings were similar to CD56 expression and superior to synaptophysin, chromogranin A, and INSM1. Musashi-1 also tended to show more diffuse and intense staining, especially in LCNEC, with more cases staining > 10% than any other existing markers (Musashi-1, 77%; INSM1, 45%; chromogranin A, 34%; synaptophysin, 41%; and CD56, 66%). In conclusion, we identified Musashi-1 as a novel immunohistochemical staining marker to aid in the diagnosis of lung NEC.

Long Non-coding RNA LINC00152 Requires EZH2 to Promote Mesothelioma Cell Proliferation, Migration, and Invasion.

BACKGROUND/AIM: Long non-coding RNAs (lncRNAs) establish gene regulatory networks in different human cancers and are involved in tumorigenesis. lncRNA LINC00152 is over-expressed in several malignant tumors and involved in tumorigenesis; however, its underlying regulatory mechanisms remain unclear. Mesothelioma, a cancer originating from mesothelial cells, is highly aggressive with a poor prognosis. Therefore, identification of new therapeutic targets is necessary for mesothelioma treatment. MATERIALS AND METHODS: Here, we conducted bioinformatics analyses of LINC00152 and enhancer of zeste homolog 2 (EZH2) expression levels and their correlation with the prognosis of patients with mesothelioma. Small interfering RNAs targeting LINC00152 and EZH2 were transfected into mesothelioma cell lines to analyze their biological functions and regulatory mechanisms. RESULTS: High LINC00152 expression was associated with a poor prognosis of patients with mesothelioma. LINC00152 knockdown inhibited the proliferation, migration, and invasion of mesothelioma cell lines. These results suggest that LINC00152 is a tumor-promoting factor in mesothelioma. EZH2 is highly expressed in mesothelioma and other malignancies. Direct interaction between LINC00152 and EZH2 is associated with cancer development and progression. When EZH2 expression was suppressed, LINC00152 knockdown did not suppress the proliferation, migration, and invasion of mesothelioma cells. Therefore, the tumor-promoting effect of LINC00152 in mesothelioma was dependent on EZH2 expression. CONCLUSION: LINC00152 promotes mesothelioma cell proliferation, migration, and invasion in cooperation with EZH2, highlighting its potential as an effective therapeutic target for mesothelioma.

Usefulness of NF2 hemizygous loss detected by fluorescence in situ hybridization in diagnosing pleural mesothelioma in tissue and cytology material: A multi-institutional study.

OBJECTIVES: BAP1, CDKN2A, and NF2 are the most frequently altered genes in pleural mesotheliomas (PM). Discriminating PM from benign mesothelial proliferation (BMP) is sometimes challenging; it is well established that BAP1 loss, determined by immunohistochemistry (IHC), and CDKN2A homozygous deletion (HD), determined by fluorescence in situ hybridization (FISH), are useful. However, data regarding the diagnostic utility of NF2 FISH in PM is limited. Thus, we performed a multi-institutional study examining the utility of NF2 alterations determined by FISH for diagnosing PM in combination with BAP1 loss and CDKN2A HD. MATERIALS AND METHODS: Multi-institutional PM cases, including 106 surgical and 107 cell block samples as well as 37 tissue cases of benign mesothelial proliferation (BMP) and 31 cell block cases with reactive mesothelial cells (RMC), were collected and analyzed using IHC for BAP1 and FISH for CDKN2A and NF2. RESULTS: In PM, NF2 FISH revealed hemizygous loss (HL) in 54.7% of tissue cases (TC) and 49.5% of cell block cases (CBC), with about 90% of HL being monosomy. CDKN2A HD or BAP1 loss were detected in 75.5%/65.4% TC or 63.6%/60% CBC, respectively. BMP or RMC showed no BAP1 loss, CDKN2A HD, or NF2 HL. For discriminating PM from BMP, a combination of BAP1 loss, CDKN2A HD, and NF2 HL yielded enhanced sensitivity of 98.1% TC/94.4% CBC. BAP1 loss, CDKN2A HD, or NF2 HL were observed in 69%, 70%, or 58% of epithelioid PM, but in 9%, 91%, or 27% of sarcomatoid PM, respectively. Histotype, histological gradings, and CDKN2A deletion status showed significant differences in overall survival, while BAP1 loss and NF2 HL did not. CONCLUSION: NF2 HL, consisting predominantly of monosomy, can be detected by FISH in both TC and CBC of PM, and is effective for distinguishing PM from BMP, especially when combined with BAP1 loss and CDKN2A HD.