Objective: ATP-binding cassette, subfamily G, member 2 (ABCG2) is a new member of the superfamily of ATP-binding cassette transporter proteins and known to be not only a member of the membrane transporters implicated in multidrug resistance, but also a molecular determinant of the side population phenotype, characteristics of which are reminiscent of stem cells. The aim of the current study was to clarify the significance of ABCG2 expression in esophageal squamous cell carcinoma (ESCC). Methods: We immunohistochemically investigated paraffin sections of 100 ESCC tumors and assessed the expression level of ABCG2 mRNA in 33 specimens by quantitative RT-PCR. Results: In the immunohistochemical study, ABCG2 expression was detectable in 61% of patients and the proportion of ABCG2-positive cells was variable (0–100%). Interestingly, the presence of ABCG2-positive cells in the tumor, regardless of their amount, was associated with poorer survival (p = 0.0088). Moreover, it was revealed to be an independent prognostic factor along with the extent of the primary tumor and positive lymph node metastasis in multivariate analysis using Cox’s regression model. In the quantitative RT-PCR study, higher tumor ABCG2 mRNA expression was associated with poorer survival (p = 0.017). Conclusions: The absolute presence of ABCG2-positive cells in the tumor is a single independent prognostic factor, suggesting the underlying roles in malignant characteristics of ESCC other than drug resistance.

Purpose: We previously reported that the expression of Aurora-A was frequently up-regulated in human esophageal squamous cell carcinoma (ESCC) tissues as well as cell lines and the up-regulation contributed to a poor prognosis. In this study, we assessed the possibility of Aurora-A suppression as a therapeutic target for ESCC using ESCC cell lines. Experimental Design: We established subclones using vector-based short hairpin RNA (shRNA). Then, we investigated the effect of Aurora-A suppression on proliferation and cell cycle changes in vitro. Next, chemosensitivity against docetaxel was investigated by tetrazolium salt–based proliferation assay (WST assay) and cell number determinations, and furthermore, the type of cell death induced by docetaxel was analyzed by flow cytometry. Finally, to examine the effect of Aurora-A shRNA on proliferation and chemosensitivity against docetaxel in vivo, a s.c. tumor formation assay in nude mice was done. Results: We established two genetically different stable cell lines (510 A and 1440 A) in which levels of Aurora-A were reduced. Cell growth was inhibited by 38.7% in 510 A and by 24.3% in 1440 A in vitro compared with empty vector–transfected controls (510 m and 1440 m), and this growth inhibition was mediated through G₂-M arrest as confirmed by flow cytometry. Next, in a WST assay, the IC₅₀ for Aurora-A shRNA-transfected cells was lower than that of empty vector–transfected cells (510 A, 2.7 × 10⁻⁷ mol/L; 510 m, 4.8 × 10⁻⁷ mol/L; 1440 A, 2.6 × 10⁻⁷ mol/L; 1440 m, 4.9 × 10⁻⁷ mol/L). In addition, 0.3 nmol/L docetaxel induced a notable level of apoptosis in Aurora-A shRNA-transfected cells compared with empty vector–transfected cells. In the assay of s.c. tumors in nude mice, tumor growth in 510 A was inhibited by 36.1% compared with that in 510 m, and in tumors treated with docetaxel, the suppression of Aurora-A resulted in 44.0% tumor growth suppression in vivo. Conclusions: These results indicated that Aurora-A might play an important role in chemosensitivity to docetaxel, and the suppression of its expression might be a potential therapeutic target for ESCC.

To elucidate the possible involvement of gankyrin in ESCC progression and the effect of its down‐regulation in ESCC, we investigated the expression of gankyrin in ESCC tissues comparing it with the corresponding normal esophageal epithelia and tested a short‐hairpin RNA (shRNA) expression vector for gankyrin in ESCC cell lines. Gankyrin protein expression in 11 ESCC cell lines (KYSE series) was examined by RT‐PCR and western blot. The expression of gankyrin mRNA in 30 ESCC tissues was compared with the corresponding normal epithelia by Real‐time PCR. Expression of gankyrin protein was immunohistochemically analyzed in the ESCC of 103 patients. A gankyrin‐shRNA vector was stably transfected into KYSE 170 cells to assess the role of gankyrin in cell motility, invasion and proliferation in vitro and tumor formation in vivo. Gankyrin expression increased in all 11 ESCC cell lines. Real‐time PCR revealed that gankyrin expression was higher in the cancerous tissue for all 30 patients. In immunohistochemistry, gankyrin overexpression was correlated with lower survival rate (p = 0.0001), extent of the primary tumor, lymph node metastasis, distant lymph node metastasis and stage (p = 0.0072, p = 0.0004, p = 0.0172 and p = 0.0002, respectively). A shRNA vector against gankyrin repressed growth, cell motility, invasiveness in vitro and tumor formation in vivo. Gankyrin overexpression is associated with poor prognosis. It may play an important role in ESCC tumor progression and could be a potentially important therapeutic gene target in ESCC.

Precision medicine promises to improve prognosis of patients affected by untreatable diseases. Patients with lung cancer (especially lung adenocarcinoma) bear an increased risk of VTE. Mutations in the EGFR and rearrangement in the ALK genes identify specific subgroups of patients. Aim of this study was to investigate the role of epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK) mutational status on the risk of venous thromboembolism (VTE) in lung adenocarcinoma. A retrospective longitudinal design was used. Patients with lung adenocarcinoma diagnosed and undergoing a mutational analysis at the Karolinska University Hospital, Stockholm, Sweden between January 2009 and September 2015 were divided in three subgroups based on their mutational status (EGFR-, ALK-mutated, unexposed group). Event-free time for VTE was assessed using Cox regression analysis based on mutation status and treatment received. Three hundred-ten patients were included. A VTE occurred in 70 (22.6%) patients. Mutation of EGFR was associated with a decreased risk of VTE (HR 0.46, 95% CI 0.23–0.94). Treatment with tyrosine kinase inhibitors (TKI) reduced the risk of VTE compared to other treatment strategies not including TKI (HR 0.42, 95% CI 0.29–0.79). Our study suggests that patients with lung adenocarcinoma bearing a EGFR-mutation have a decreased risk of VTE compared with patients with other forms of lung adenocarcinoma. Targeted therapy with TKI alone or in combination with other treatments seems to reduce the risk of VTE compared to other treatments not including TKI.

Dissemination of non-small-cell lung cancer (NSCLC) in the central nervous system is a frequent and challenging clinical problem. Systemic or local therapies rarely prolong survival and have modest activity regarding local control. Alterations in gene expression in brain metastasis versus primary tumour may increase aggressiveness and impair therapeutic efforts. We identified 25 patients with surgically removed NSCLC brain metastases in two different patient cohorts. For 13 of these patients, primary tumour samples were available. Gene expression analysis using the nCounter® PanCancer Immune Profiling gene expression panel (nanoString technologies Inc.) was performed in brain metastases and primary tumour samples. Identification of differentially expressed genes was conducted on normalized data using the nSolver analysis software. We compared gene expression patterns in brain metastases with primary tumours. Brain metastasis samples displayed a distinct clustering pattern compared to primary tumour samples with a statistically significant downregulation of genes related to immune response and immune cell activation. Results from KEGG term analysis on differentially expressed genes revealed a concomitant enrichment of multiple KEGG terms associated with the immune system. We identified a 12-gene immune signature that clearly separated brain metastases from primary tumours. We identified a unique gene downregulation pattern in brain metastases compared with primary tumours. This finding may explain the lower intracranial efficacy of systemic therapy, especially immunotherapy, in brain metastasis of patients with NSCLC.