Noriaki Sunaga

Combined survival analysis of prospective clinical trials of gefitinib for non-small cell lung cancer with EGFR mutations.

Purpose: Somatic mutations of the epidermal growth factor receptor (EGFR) gene are associated with an increased response to gefitinib in patients with non–small cell lung cancer. We have examined the impact of gefitinib on progression-free survival and overall survival in patients with EGFR mutation–positive non–small cell lung cancer. Experimental Design: We searched for all clinical trials that prospectively evaluated the efficacy of gefitinib for advanced non–small cell lung cancer with EGFR mutations in Japan. We did a combined analysis based on individual patient data from the identified trials. Results: Seven eligible trials were identified for a total of 148 non–small cell lung cancer patients with EGFR mutations. The overall response rate to gefitinib was 76.4% [95% confidence interval (95% CI), 69.5-83.2]. The median progression-free survival and overall survival were 9.7 months (95% CI, 8.2-11.1) and 24.3 months (95% CI, 19.8-28.2), respectively. Good performance status and chemotherapy-naïve status were significantly associated with a longer progression-free survival or overall survival. Of the 148 patients, 87 received gefitinib as a first-line therapy, whereas 61 received systemic chemotherapy before gefitinib treatment. The median progression-free survival after the start of first-line therapy was significantly longer in the gefitinib-first group than in the chemotherapy-first group (10.7 versus 6.0 months; P < 0.001), whereas no significant difference in median overall survival was apparent between the two groups (27.7 versus 25.7 months; P = 0.782). Conclusions: Gefitinib monotherapy confers substantial clinical benefit in terms of progression-free survival and overall survival in non–small cell lung cancer patients with EGFR mutations. Randomized trials comparing chemotherapy with gefitinib as a first-line treatment are warranted in such patients.

Different Roles for Caveolin-1 in the Development of Non-Small Cell Lung Cancer versus Small Cell Lung Cancer

Caveolin-1 (CAV1), an essential structural constituent of caveolae that plays an important role in cellular processes such as transport and signaling, has been implicated in the development of human cancers. However, it is unclear whether CAV1 is acting like an oncogene or tumor suppressor gene. We found that CAV1 expression was reduced or absent in 95% of small cell lung cancers (SCLCs; n = 21 lines), whereas it was retained in 76% of non-small cell lung cancers (NSCLCs; n = 25 lines) compared with normal human lung epithelial cultures, where it was abundantly expressed. CAV1 expression was tightly linked to the ability to grow attached to the plastic cell culture surface, whereas CAV1-nonexpressing lung cancers of both SCLC and NSCLC type grew as suspension cultures. In addition, attached lung cancer cultures expressed phosphorylated focal adhesion kinase, whereas suspension cultures did not. Lack of CAV1 expression was tightly associated with CAV1 promoter methylation (P < 0.0001) such that CAV1 methylation was found in 93% of SCLCs (n = 15) and 9% of NSCLCs (n = 11), whereas 5-aza-2′deoxycytidine treatment restored CAV1 expression in SCLCs. Exogenous CAV1 expression in SCLCs significantly inhibited soft-agar colony formation but did not lead to attachment. By contrast, CAV1 knockdown in NSCLCs mediated by small interfering RNA against CAV1 led to inhibition of cellular proliferation and soft-agar and liquid colony formation. Importantly, CAV1 knockdown led to reduced phospho-focal adhesion kinase and RalA, but not RalB, levels in NSCLC cells. These results suggest different roles for CAV1 in SCLC, where CAV1 acts like a tumor suppressor gene, and NSCLC, where it appears required for survival and growth.

Constitutive activation of the Wnt signaling pathway byCTNNB1 (?-catenin) mutations in a subset of human lung adenocarcinoma

Constitutive activation of the Wnt signaling pathway as a result of genetic alterations of APC, AXIN1, and CTNNB1 has been found in various human cancers, including those of the colon, liver, endometrium, ovary, prostate, and stomach. To investigate the pathogenetic significance of constitutive activation of the Wnt signaling pathway in human lung carcinogenesis, CTNNB1 alterations in exon 3, a region known to represent a mutation hot spot, were screened in 46 lung cancer cell lines and 47 primary lung cancers. Missense mutations causing substitutions of Ser/Thr residues critical for regulation by GSK‐3β were detected in one (2%) of the cell lines, A427, and two (4%) of the surgical specimens. The three lung cancers with CTNNB1 mutations were adenocarcinomas. To explore the prevalence of constitutive activation of the Wnt signaling pathway in human lung cancer, we assessed 15 lung cancer cell lines representing major histological subtypes of lung cancers for constitutive Tcf transcriptional activity (CTTA). CTTA was observed only in the A427 adenocarcinoma cell line, but not in the remaining 14 cell lines. The data indicate that constitutive activation of the Wnt signaling pathway caused by CTNNB1 mutation is involved in the development and/or progression of a subset of lung carcinoma, preferentially in adenocarcinoma.

l-type amino acid transporter 1 and CD98 expression in primary and metastatic sites of human neoplasms.

The significance of l‐type amino acid transporter (LAT) 1 expression remains unclear in the metastatic process of human neoplasms, whereas experimental studies have demonstrated that LAT1 is associated with the metastatic process of cancer cells. We compared the immunohistochemical expression of LAT1 and CD98 between the primary site and a concordant pulmonary metastatic site in 93 cancer patients, all of whom had undergone thoracotomy. LAT1, CD98, Ki‐67 labeling index, vascular endothelial growth factor (VEGF), CD31, and CD34 were analyzed by immunohistochemical staining in the resected tumors of 93 cancer patients: 45 colon cancers; nine breast cancers; eight head and neck cancers; 11 genital cancers; 14 soft‐tissue sarcomas; and six other cancers. The expression of these markers was significantly higher in the metastatic sites than in the primary sites. In total, the positive rates of LAT1, CD98, Ki‐67, VEGF, CD31, and CD34 were 40, 24, 56, 41, 45, and 39%, respectively, in the primary sites and 65, 45, 84, 67, 73, and 61%, respectively, in the metastatic sites. LAT1 expression was closely correlated with CD98 expression, angiogenesis, and cell proliferation. The association between LAT1 and CD98 expression was strongest in the primary and metastatic sites. The present study suggests that overexpression of LAT1 and CD98 has an important role to play in the metastatic process of variable human neoplasms. Moreover, LAT1 expression was significantly correlated with cell proliferation and angiogenesis. (Cancer Sci 2008; 99: 2380–2386)

Fluorine-18-α-Methyltyrosine Positron Emission Tomography for Diagnosis and Staging of Lung Cancer: A Clinicopathologic Study

Purpose:l-[3-18F]-α-Methyltyrosine ([18F]FMT) is an amino acid tracer for positron emission tomography (PET). We evaluated the diagnostic usefulness of [18F]FMT PET in non–small-cell lung cancer (NSCLC) patients. Tumor uptake of [18F]FMT was compared with that of 2-[18F]-fluoro-2-deoxy-d-glucose ([18F]FDG) and correlated with L-type amino acid transporter 1 (LAT1) expression. Experimental Design: Fifty NSCLC patients were enrolled in this study, and a pair of PET study with [18F]FMT and [18F]FDG was done. LAT1 expression and Ki-67 labeling index of the resected tumors were analyzed by immunohistochemical staining. Results: For the primary tumor detection, [18F]FMT PET exhibited a sensitivity of 90% whereas the sensitivity for [18F]FDG PET was 94%. For lymph node staging, the sensitivity and specificity of [18F]FMT PET were 57.8% and 100%, and those of [18F]FDG PET were 65.7% and 91%, respectively. The expression of LAT1 in squamous cell carcinoma and large cell carcinoma was significantly higher than that in adenocarcinoma. [18F]FMT uptake was also higher in squamous cell carcinoma and large cell carcinoma than in adenocarcinoma. Uptake of [18F]FMT in the tumor is closely correlated with LAT1 expression (ρ = 0.890). Conclusion: [18F]FMT PET had no false-positives in the detection of primary tumor and lymph node metastasis and could improve the diagnostic performance in NSCLC. Uptake of [18F]FMT correlated with the expression of LAT1 that showed a significant association with cellular proliferation.

Prognostic significance of L-type amino acid transporter 1 (LAT1) and 4F2 heavy chain (CD98) expression in stage I pulmonary adenocarcinoma

BACKGROUND The purpose of this study was to evaluate the prognostic value of l-type amino acid transporter 1 (LAT1) and 4F2 heavy chain (CD98) expression in patients with stage I pulmonary adenocarcinoma. METHODS A total of 139 consecutive patients with pathologic stage I pulmonary adenocarcinoma were retrospectively reviewed. Expression of LAT1, CD98, Ki-67 labeling index, vascular endothelial growth factor (VEGF) and microvessel density (MVD) was also evaluated immunohistochemically and correlated with the prognosis of patients after complete resection of the tumor. RESULTS LAT1 and CD98 expression were positive in 23% (32/139) and 22% (31/139), respectively (p=0.887). LAT1 with CD98 expression was recognized in 15% (21/139). LAT1 expression was significantly correlated with CD98, Ki-67 labeling index, VEGF, and MVD. The 5-year survival rates of LAT1-positive and -negative patients and CD98-positive and -negative patients, were 60.2 and 95.2% (p<0.0001) and 72.5 and 93.4% (p=0.0008), respectively. Univariate analysis disclosed that cellular proliferation and MVD in the tumor were significant prognostic factors. However, multivariate analysis confirmed that positive expression of LAT1 and CD98 was an independent factor for predicting a poor prognosis. CONCLUSION The overexpression of LAT1 and CD98 is a pathological factor to predict the prognosis in patients with resectable stage I pulmonary adenocarcinoma.

Protective effect of resolvin E1 on the development of asthmatic airway inflammation.

Resolvin E1 (RvE1) is an anti-inflammatory lipid mediator derived from the omega-3 fatty acid eicosapentaenoic acid (EPA), and strongly acts in the resolution of inflammation. We previously reported that RvE1 dampens airway inflammation and hyperresponsiveness in a murine model of asthma. In the present study, to elucidate the effects of RvE1 on the development of asthmatic airway inflammation, we investigated whether RvE1 acts on different phases of an OVA-sensitized and -challenged mouse model of asthma. RvE1 treatments at the time of either OVA sensitization or at the time of OVA challenge were investigated and compared with RvE1 treatments at the time of both OVA sensitization and challenge. After RvE1 was administered to mice intraperitoneally at the time of both OVA sensitization and challenge, there were decreases in airway eosinophil and lymphocyte recruitment, as well as a reduction in Th2 cytokine and airway hyperresponsiveness. RvE1 treatment at the time of either OVA sensitization or challenge also improved AHR and airway inflammation. Our results suggest that RvE1 acts on several phases of asthmatic inflammation and may have anti-inflammatory effects on various cell types.

Serum Pro-Gastrin-Releasing Peptide Is a Useful Marker for Treatment Monitoring and Survival in Small-Cell Lung Cancer

We investigated the usefulness of serum pro-gastrin-releasing peptide (Pro-GRP) as a tumor marker for diagnosis, treatment monitoring and the prediction of relapse and prognosis in patients with small-cell lung cancer (SCLC). Serum samples were obtained from 127 patients with primary lung cancer (48 patients with small-cell carcinoma, 31 with adenocarcinoma, 36 with squamous cell carcinoma and 11 with large-cell carcinoma). The cutoff levels of serum Pro-GRP and neuron-specific enolase (NSE) were set at 46 pg/ml and 10 ng/ml, respectively. The specificity of Pro-GRP was significantly higher than that of NSE (Pro-GRP: 93.7%, NSE: 65.8%, p < 0.01). According to the histological type of lung cancer, the positive rates of Pro-GRP were 75% (36/48) in the small-cell carcinomas, 9.7% (3/31) in the adenocarcinomas, 5.6% (2/36) in the squamous cell carcinomas and 0% (0/10) in the large cell carcinomas. The median levels of Pro-GRP in limited disease (LD) and extensive disease (ED) patients were 199 and 295.5 pg/ml, whereas those of NSE were 14.8 and 29.3 ng/ml, respectively. The positive rates of Pro-GRP in LD and ED patients were 80.0% (16/20) and 71.4% (20/28), whereas those of NSE were 70.0% (14/20) and 89.3% (25/28), respectively. The positive rate of NSE tended to elevate with the progression of disease, whereas that of Pro-GRP was already high at an early stage. Among the 29 patients with SCLC who could be followed, the serum Pro-GRP levels of 18 responders were significantly decreased after treatment (p < 0.01), whereas those of the 11 nonresponders were not significantly different between before and after treatment (p = 0.72). In the 9 patients with SCLC who relapsed, the serum Pro-GRP levels were again elevated at the time of relapse. Seventeen patients whose ratio of the Pro-GRP level after treatment to the level before treatment was below 50% (taking the levels before treatment as 100%) survived significantly longer than did the patients whose ratio was over 50% (p < 0.01). The results of the present study suggest that serum Pro-GRP has high specificity and could be a useful marker of SCLC for treatment monitoring and prognosis.

L-type amino acid transporter 1 expression is a prognostic marker in patients with surgically resected stage I non-small cell lung cancer.

Aim:  To evaluate the prognostic value of L‐type amino acid transporter 1 (LAT1) in patients with stage I non‐small cell lung cancer (NSCLC).

18F-FMT Uptake Seen Within Primary Cancer on PET Helps Predict Outcome of Non–Small Cell Lung Cancer

L-[3-18F]-α-methyl tyrosine (18F-FMT) is an amino-acid tracer for PET imaging. We evaluated the prognostic significance of 18F-FMT PET in patients with non–small cell lung cancer. Methods: Ninety-eight patients (80 men and 18 women; age range, 42–82 y; median age, 69 y) with stage I–IV non–small cell lung cancer were enrolled in this study. They included 57 with adenocarcinoma, 31 with squamous cell carcinoma, 5 with large cell carcinoma, and 5 with other conditions. The median follow-up duration was 17.0 mo. A pair of PET studies with 18F-FMT and 18F-FDG was performed, and tracer uptake by the primary tumor was evaluated using the maximal standardized uptake value (SUVmax). Overall survival and disease-free survival were calculated by the Kaplan–Meier method. The prognostic significance was assessed by univariate and multivariate analyses. Results: The best discriminative SUVmax cutoffs for 18F-FMT and 18F-FDG in the primary tumors were 1.6 and 11, respectively. In the univariate analysis, a high SUVmax was significant in predicting poor overall survival for 18F-FMT (P = 0.0129) and 18F-FDG PET (P = 0.0481). According to histologic types, 18F-FMT and 18F-FDG uptake were a stronger prognostic predictor in adenocarcinoma than in nonadenocarcinomatous disease. Patients with a high SUVmax for 18F-FMT showed significantly worse disease-free survival rates than those with a low SUVmax, and multivariate analysis confirmed that a high SUVmax for 18F-FMT was an independent and significant factor in predicting a poor prognosis in patients with adenocarcinoma (P = 0.0191). Conclusion: Uptake of 18F-FMT in primary tumors was an independent prognostic factor in patients with pulmonary adenocarcinoma.