Identification of genes and pathways, including the CXCL2 axis, altered by DNA methylation in hepatocellular carcinoma.

PURPOSE: Recent genetic studies have suggested that tumor suppressor genes are often silenced during carcinogenesis via epigenetic modification caused by methylation of promoter CpG islands. Here, we characterized genes inactivated by DNA methylation in human hepatocellular carcinoma (HCC) to identify the genes and pathways involved in DNA methylation in hepatocellular carcinoma. METHODS: Eight HCC-derived cell lines were treated with a DNA demethylating agent, 5-aza-2'-deoxycytidine. Additionally, 100 pairs of primary HCC and adjacent non-cancerous tissues as well as 15 normal liver tissues were analyzed by comprehensive gene expression analysis using microarrays. Moreover, gene set enrichment analysis identified the major molecular pathways associated with DNA methylation. Validation of gene expression and DNA methylation status was performed by real-time PCR after bisulfite modification. RESULTS: We showed that CXCL2, an immune-related chemokine, expression was significantly downregulated in tumor tissues and also significantly upregulated by DAC treatment in cell lines. Furthermore, we observed a statistically significant difference in methylation status between normal liver tissues and tumor tissues (P < 0.05). In addition, tumors with higher CXCL2 expression included significantly more numbers of multiple tumors than the lower expression group. CONCLUSIONS: We identified CXCL2, an immune-related chemokine, decreased in hepatocellular carcinoma and the regulation mechanism may be controlled by methylation. Further studies should be warranted to examine if and to what extent the gene is actually suppressed by methylation and if there is a possibility that the CXCL2 axis plays a role for diagnosis and treatment of hepatocellular carcinoma.

Unique MicroRNA and mRNA Interactions in EGFR-Mutated Lung Adenocarcinoma.

The EGFR gene was one of the first molecules to be selected for targeted gene therapy. EGFR-mutated lung adenocarcinoma, which is responsive to EGFR inhibitors, is characterized by a distinct oncogenic pathway in which unique microRNA (miRNA)⁻mRNA interactions have been observed. However, little information is available about the miRNA⁻mRNA regulatory network involved. Both miRNA and mRNA expression profiles were investigated using microarrays in 155 surgically resected specimens of lung adenocarcinoma with a known EGFR mutation status (52 mutated and 103 wild-type cases). An integrative analysis of the data was performed to identify the unique miRNA⁻mRNA regulatory network in EGFR-mutated lung adenocarcinoma. Expression profiling of miRNAs and mRNAs yielded characteristic miRNA/mRNA signatures (19 miRNAs/431 mRNAs) in EGFR-mutated lung adenocarcinoma. Five of the 19 miRNAs were previously listed as EGFR-mutation-specific miRNAs (i.e., miR-532-3p, miR-500a-3p, miR-224-5p, miR-502-3p, and miR-532-5p). An integrative analysis of miRNA and mRNA expression revealed a refined list of putative miRNA⁻mRNA interactions, of which 63 were potentially involved in EGFR-mutated tumors. Network structural analysis provided a comprehensive view of the complex miRNA⁻mRNA interactions in EGFR-mutated lung adenocarcinoma, including DUSP4 and MUC4 axes. Overall, this observational study provides insight into the unique miRNA⁻mRNA regulatory network present in EGFR-mutated tumors. Our findings, if validated, would inform future research examining the interplay of miRNAs and mRNAs in EGFR-mutated lung adenocarcinoma.

Association of tumor TROP2 expression with prognosis varies among lung cancer subtypes.

TROP2 is a transmembrane glycoprotein that is overexpressed in various cancers. Emerging evidence suggests that TROP2-targeting therapies are efficacious and safe in patients with multiple prior treatments. TROP2 is a promising target for lung cancer treatment; however, little is known regarding the association of TROP2 expression with clinicopathological/molecular features, including prognosis, in lung cancer. We examined consecutive cases of adenocarcinoma, squamous cell carcinoma (SqCC), and high-grade neuroendocrine tumor (HGNET) for the membranous expression of TROP2 using immunohistochemistry. High TROP2 expression was observed in 64% (172/270) of adenocarcinomas, 75% (150/201) of SqCCs, and 18% (21/115) of HGNETs. Intriguingly, the association of TROP2 expression with mortality was dependent on the lung cancer subtype. High TROP2 expression was associated with higher lung cancer-specific mortality in adenocarcinomas [univariable hazard ratio (HR) = 1.60, 95% confidence interval (CI) = 1.07-2.44, P = 0.022)], but not in SqCCs (univariable HR = 0.79, 95% CI = 0.35-1.94, P = 0.79). In HGNETs, high TROP2 expression was associated with lower lung cancer-specific mortality in both univariable and multivariable analyses (multivariable HR = 0.13, 95% CI = 0.020-0.44, P = 0.0003). Our results suggest a differential role for TROP2 in different lung cancer subtypes.

Tumor B7-H3 (CD276) expression and smoking history in relation to lung adenocarcinoma prognosis.

OBJECTIVES: Compared with non-smoking counterparts, smoking-associated lung cancers have a higher mutational load, resulting in the creation of more tumor neoantigens and increased immunogenicity. B7-H3 (also known as CD276) belongs to a family of immune modulators that includes PD-1 and PD-L1 (also known as B7-H1 or CD274). Considering the evidence that PD-L1 inhibitors have been shown to be more effective against lung cancer in smokers, we herein examined the prognostic interaction of tumor B7-H3 expression level with smoking history in lung adenocarcinoma patients. MATERIALS AND METHODS: Using tissue microarrays comprising 270 consecutive cases of lung adenocarcinoma, we evaluated tumor B7-H3 expression by immunohistochemistry. We examined the prognostic association between B7-H3 expression levels and smoking history, using Cox proportional hazards regression analysis and the log-rank test. Additionally, we used logistic regression analysis to examine the correlations between B7-H3 expression levels and clinicopathological/molecular features of lung adenocarcinoma. RESULTS: The association of B7-H3 expression with survival differed by smoking history (Pinteraction=0.014); high B7-H3 expression was associated with decreased lung cancer-specific survival in moderate/heavy-smoking patients (smoking index [SI]≥400) (hazard ratio [HR]=3.07, 95% confidence interval [CI]=1.74-5.49, P=0.0001; log-rank: P<0.0001), but not in non/light-smoking patients (SI<400) (HR=1.14, 95% CI=0.63-1.96, P=0.64; log-rank: P=0.64). Interestingly, in moderate/heavy-smoking patients, high B7-H3 expression was associated with decreased survival in stage I cancer (log-rank; P=0.0005), whereas it showed no significant difference of survival in stage II-IV cancer (P=0.37). High B7-H3 expression was associated with smokers (univariable odds ratio [OR]=2.63, 95% CI=1.51-4.65; P=0.0005) and independently associated with EGFR wild-type status (multivariable OR=2.80, 95% CI=1.38-5.84; P=0.0042). CONCLUSIONS: We demonstrated that the prognostic association of B7-H3 expression indeed differed according to smoking history. Our study also showed the significant association of high B7-H3 expression with EGFR wild-type and smoking patients, indicating the potential effectiveness of anti-B7-H3 therapy for EGFR wild-type or smokers' lung adenocarcinoma.

WITHDRAWN: Tumor B7-H3 (CD276) expression and smoking history in relation to lung adenocarcinoma prognosis.

The Publisher regrets that this article is an accidental duplication of an article that has already been published in The Journal of Lung Cancer - http://dx.doi.org/10.1016/j.lungcan.2016.11.013. Please see online announcement for additional details. The duplicate article has therefore been withdrawn. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.

Relationship of tumor PD-L1 expression with EGFR wild-type status and poor prognosis in lung adenocarcinoma.

BACKGROUND: Programmed death-ligand 1 is an immune modulator that promotes immunosuppression by binding to programmed death-1 of T-lymphocytes. Whereas programmed death-ligand 1 expression has been shown to be associated with the clinical response to anti-programmed death-ligand 1 antibody, the association of tumor programmed death-ligand 1 expression with clinicopathological/molecular features and with prognosis remains inconclusive in lung adenocarcinoma. We therefore examined the association of programmed death-ligand 1 expression with the clinicopathological/molecular features and prognosis of lung adenocarcinoma. METHODS: Using tissue microarrays of 268 consecutive cases of lung adenocarcinoma, we evaluated programmed death-ligand 1 expression by immunohistochemistry. We examined the association of programmed death-ligand 1 expression with clinicopathological and molecular features. We also examined the prognostic association of programmed death-ligand 1 expression, using the log-rank test as well as Cox proportional hazards regression models to compute the mortality hazard ratio (HR). RESULTS: Programmed death-ligand 1 immunoreactivity (at least 5% of the tumor cells) was observed in 43 (16%) of 268 cases of lung adenocarcinoma. Programmed death-ligand 1 positivity was associated with less tumor differentiation (P < 0.0001) and EGFR wild-type status (P = 0.0008). In a multivariable logistic regression analysis, less tumor differentiation was independently associated with programmed death-ligand 1 positivity (multivariable odds ratio, 6.54; 95% confidence interval [CI], 2.37-23.3; P = 0.0001). Programmed death-ligand 1 positivity was associated with a poor prognosis for lung cancer-specific survival (log-rank, P = 0.019; HR, 1.73; 95% CI, 1.06-2.72; P = 0.030) and overall survival (log-rank, P = 0.0014; HR, 1.88; 95% CI, 1.25-2.74). CONCLUSION: Our study demonstrated that programmed death-ligand 1 positivity in lung adenocarcinoma was associated with less tumor differentiation and EGFR wild-type status, as well as a poor prognosis.