Kyoichi Kaira

Prognostic significance of L-type amino acid transporter 1 expression in resectable stage I-III nonsmall cell lung cancer

The clinical significance of L-type amino acid transporter 1 (LAT1) expression remains unclear, whereas many experimental studies have demonstrated that LAT1 is associated with the proliferation of cancer cells. The purpose of this study was to evaluate the prognostic value of LAT1 in patients with nonsmall cell lung cancer (NSCLC). A total of 321 consecutive patients with completely resected pathologic stage I–III NSCLC were retrospectively reviewed. Expression of LAT1 and proliferative activity, as determined by the Ki-67 labelling index, was also evaluated immunohistochemically and correlated with the prognosis of patients who underwent complete resection of the tumour. Expression of LAT1 was positive in 163 patients (51%) (29% of adenocaricnoma (58 of 200 patients), 91% of squamous cell carcinoma (91 of 100 patients), and 67% of large cell carcinoma (14 of 21 patients)). The 5-year survival rate of LAT1-positive patients (51.8%) was significantly worse than that of LAT1-negative patients (87.8%; P<0.001). L-type amino acid transporter 1 expression was significantly associated with lymph node metastasis and disease stage. Multivariate analysis confirmed that positive expression of LAT1 was an independent factor for predicting a poor prognosis. There was a significant correlation between LAT1 expression and Ki-67 labelling index. LAT1 expression is a promising pathological factor to predict the prognosis in patients with resectable stage I–III NSCLC.

Biologic Correlation of 2-[18F]-Fluoro-2-Deoxy-D-Glucose Uptake on Positron Emission Tomography in Thymic Epithelial Tumors

PURPOSE The usefulness of 2-[(18)F]-fluoro-2-deoxy-D-glucose ([(18)F]FDG) positron emission tomography (PET) can help predict the grade of malignancy and staging in thymic epithelial tumors. However, no satisfactory biologic explanation exists for this phenomenon. The aim of this study was to investigate the underlying biologic mechanisms of [(18)F]FDG uptake. PATIENTS AND METHODS Forty-nine patients with thymic epithelial tumors who underwent [(18)F]FDG PET were included in this study. Tumor sections were stained by immunohistochemistry for glucose transporter 1 (GLUT1), glucose transporter 3 (GLUT3), hypoxia-inducible factor-1 alpha (HIF-1alpha), vascular endothelial growth factor (VEGF), microvessels (CD31 and CD34), cell cycle control marker (p53), and apoptosis marker (bcl-2). We also conducted an in vitro study of [(18)F]FDG uptake in a thymic tumor cell line. RESULTS There was a positive correlation between [(18)F]FDG uptake and GLUT1 (P < .0001), HIF-1alpha (P = .0036), VEGF (P < .0001), microvessel density (MVD; P < .0001), and p53 (P = .0002). GLUT3 and bcl-2 showed no positive correlation with [(18)F]FDG uptake. The expression of Glut1, HIF-1alpha, VEGF, CD31, CD34, and p53 was also significantly associated with the grade of malignancy and poor outcome in thymic epithelial tumors, whereas this relationship was not observed in GLUT3 and bcl-2. Our in vitro study demonstrated that upregulation of GLUT1 and HIF-1alpha was closely associated with [(18)F]FDG uptake into thymic tumor cell. CONCLUSION [(18)F]FDG uptake in thymic epithelial tumors is determined by the presence of glucose metabolism (GLUT1), hypoxia (HIF-1alpha), angiogenesis (VEGF and MVD), and cell cycle regulator (p53).

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)

Prognostic Impact of Circulating Tumor Cells in Patients with Small Cell Lung Cancer

Background: Enumeration of circulating tumor cells (CTCs) may be valuable for prognostic assessment in lung cancer patients. In this study, we report the clinical significance of CTCs in small cell lung cancer (SCLC). Methods: In total, 51 consecutive patients newly diagnosed as having SCLC and starting chemotherapy or chemoradiotherapy were prospectively enrolled. Blood samples were drawn at the baseline, after chemotherapy, and at relapse. CTCs were isolated using the CellSearch System (Veridex LLC). Thresholds of 1 to 100 cells at the baseline were systematically correlated with the overall survival. The optimal cutoff was determined by comparing the Cox proportional hazard ratios (HRs). Results: Two or more CTCs were detected at baseline in 35 patients (68.6%; 95% confidence interval, 55.0–79.7). The HR signifying the difference between the unfavorable (more than or equal to threshold) and favorable (less than threshold) groups was maximal at the threshold of 8 CTCs (HR, 3.50; 95% confidence interval, 1.45–8.60). Patients with ≥8 CTCs had worse survival than those with <8 CTCs at baseline (p = 0.0014). Patients with ≥8 CTCs posttreatment or at relapse also showed worse survival than those with <8 CTCs (p = 0.0096 and <0.0001). Patients whose baseline and posttreatment CTC levels remained <8 tended to show better survival than those whose CTC level converted from ≥8 to <8 cells (p = 0.0288) or whose posttreatment CTC level was ≥8 cells (p = 0.0047). Conclusions: CTCs were highly detectable in SCLC, and higher CTC levels were strongly associated with worse survival. Consistently favorable CTC levels were associated with favorable outcomes.

Knockdown of oncogenic KRAS in non-small cell lung cancers suppresses tumor growth and sensitizes tumor cells to targeted therapy

Oncogenic KRAS is found in more than 25% of lung adenocarcinomas, the major histologic subtype of non–small cell lung cancer (NSCLC), and is an important target for drug development. To this end, we generated four NSCLC lines with stable knockdown selective for oncogenic KRAS. As expected, stable knockdown of oncogenic KRAS led to inhibition of in vitro and in vivo tumor growth in the KRAS-mutant NSCLC cells, but not in NSCLC cells that have wild-type KRAS (but mutant NRAS). Surprisingly, we did not see large-scale induction of cell death and the growth inhibitory effect was not complete. To further understand the ability of NSCLCs to grow despite selective removal of mutant KRAS expression, we conducted microarray expression profiling of NSCLC cell lines with or without mutant KRAS knockdown and isogenic human bronchial epithelial cell lines with and without oncogenic KRAS. We found that although the mitogen-activated protein kinase pathway is significantly downregulated after mutant KRAS knockdown, these NSCLCs showed increased levels of phospho-STAT3 and phospho–epidermal growth factor receptor, and variable changes in phospho-Akt. In addition, mutant KRAS knockdown sensitized the NSCLCs to p38 and EGFR inhibitors. Our findings suggest that targeting oncogenic KRAS by itself will not be sufficient treatment, but may offer possibilities of combining anti-KRAS strategies with other targeted drugs. Mol Cancer Ther; 10(2); 336–46. ©2011 AACR.

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.

Efficacy of gefitinib for non-adenocarcinoma non-small-cell lung cancer patients harboring epidermal growth factor receptor mutations : A pooled analysis of published reports

The efficacy of gefitinib for patients with non‐adenocarcinoma non‐small‐cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR) mutations is unclear, because only a small percentage of patients enrolled in the clinical trials to evaluate the efficacy of gefitinib for tumors harboring EGFR mutation were non‐adenocarcinoma NSCLC. A pooled analysis was conducted to clarify the efficacy of gefitinib for non‐adenocarcinoma NSCLC patients harboring EGFR mutations. A systematic search of the PUBMED databases was conducted to identify all clinical reports that contained advanced non‐adenocarcinoma NSCLC patients harboring EGFR mutations and treated with gefitinib. The selected patients were advanced non‐adenocarcinoma NSCLC patients harboring EGFR mutations who were treated with gefitinib and described in reports containing the data of the histology, status of EGFR mutations and response to gefitinib. This study selected 33 patients from 15 reports. Twenty‐seven and three of the 33 patients were squamous cell carcinoma and adenosquamous cell carcinoma, respectively. One patient each had large‐cell carcinoma, pleomorphic carcinoma and spindle cell carcinoma. Twenty‐one patients (64%) had sensitive EGFR mutations. The response rate (RR), disease control rate (DCR) and median progression‐free survival (mPFS) was 27%, 67–70% and 3.0 months, respectively. These factors were statistically significantly inferior in the non‐adenocarcinoma NSCLC patients harboring EGFR mutations to adenocarcinoma patients harboring EGFR mutations selected from the same published reports (RR: 27%vs 66%, P = 0.000028; DCR: 67–70%vs 92–93%, P = 0.000014; mPFS: 3.0 vs 9.4 months, P = 0.0001, respectively). Gefitinib is less effective in non‐adenocarcinoma NSCLC harboring EGFR mutations than adenocarcinoma harboring EGFR mutations. (Cancer Sci 2011; 102: 1032–1037)

The Risk of Cytotoxic Chemotherapy-Related Exacerbation of Interstitial Lung Disease with Lung Cancer

Introduction: It is unknown what type of interstitial lung disease (ILD) has high risk for chemotherapy-related exacerbation of ILD. We investigated the risk of exacerbation of ILD for patients with lung cancer with ILD. Methods: One hundred nine patients with lung cancer with ILD treated with cytotoxic chemotherapy at Shizuoka Cancer Center between August 2002 and April 2010 were retrospectively reviewed. Results: On pretreatment computed tomography (CT) of the chest, 69 patients (63%) were identified with usual interstitial pneumonia (UIP) pattern, and 40 patients (37%) had non-UIP pattern. Patients with UIP pattern developed cytotoxic chemotherapy-related exacerbation of ILD more frequently than those with non-UIP pattern (30 versus 8%, p = 0.005). The incidence of grade 5 pulmonary toxicities was 9% in patients with UIP pattern, compared with 3% in those with non-UIP pattern. Multivariate analyses demonstrated that age (<70 years) and CT pattern (UIP) were significant independent risk factors for cytotoxic chemotherapy-related exacerbation of ILD. In small cell lung cancer, overall survival (OS) from the start of first-line chemotherapy was significantly shorter in UIP pattern than non-UIP pattern (median OS: 9 versus 16 months, p = 0.0475), whereas there was no significant difference in patients with non-small cell lung cancer (median OS: 12 versus 9 months, p = 0.2529). Conclusions: Our results indicated that the incidence of exacerbation of ILD was significantly higher in patients with lung cancer with UIP pattern on CT findings than in those with non-UIP pattern. Therefore, great care is required when administering cytotoxic chemotherapy agents for patients with lung cancer with UIP pattern.

Significance of epidermal growth factor receptor gene mutations in squamous cell lung carcinoma

Epidermal growth factor receptor (EGFR) gene mutations have been reported to be clinically significant in non-small cell lung cancer (NSCLC). However, because most previous studies focused only on adenocarcinomas, EGFR mutations in other histotypes are poorly investigated. We evaluated the frequency of EGFR gene mutations in squamous cell carcinoma (SCC) and its clinicopathological features. In total, 89 frozen tumor specimens that had been first diagnosed as SCCs, were examined for EGFR mutations in exons 19 and 21 using direct sequencing, PNA-enriched sequencing and SmartAmp2. Additionally, pathological investigation, including immunostaining for p63 and TTF-1, alcian blue staining and EGFR mutation-specific immunohistochemistry in mutation-positive samples was also performed. The frequency of EGFR mutations was 5.6% (5/89); all mutations were deletions in EGFR exon 19. Immunohistological investigation of these samples revealed that two of five were positive for p63 and TTF-1 staining, and showed production of mucin, as evidenced by alcian blue staining. Consequently, three of the samples were considered to be true SCC at final pathological diagnosis, while the remaining two samples were revised to adenosquamous carcinoma and adenocarcinoma. The final frequency of the EGFR mutations in true SCC was 3.4% (3/87). In conclusion, EGFR mutations were found in a small, but significant, number of SCC tumor samples and thus EGFR mutational analysis was useful in the accurate diagnosis of SCC. Our data demonstrate that EGFR mutational analysis should be performed not only in adenocarcinoma, but also in SCC to allow accurate diagnosis and treatment.

Pulmonary Pleomorphic Carcinoma: A Clinicopathological Study Including EGFR Mutation Analysis

Background: Pulmonary pleomorphic carcinoma is a rare epithelial tumor and has an aggressive clinical course. As few studies of pulmonary pleomorphic carcinoma have been described, the clinicopathological characteristics of the disease remain unclear. Especially, the information on the epidermal growth factor receptor (EGFR) mutation status of pulmonary pleomorphic carcinoma is sparse. Methods: We retrospectively examined 17 patients with pulmonary pleomorphic carcinoma. EGFR mutation and Ki-67 labeling index were investigated in these patients. Results: The median age of the patients was 72 years (range, 47–84 years). Thirteen patients were men and four were women. EGFR mutation was observed in 3 (18%) of 17 patients. The median value of Ki-67 labeling index was 62% (range, 20–87%). Positron emission tomography with 18-fluorodeoxy-glucose was performed in 16 patients, and the standardized uptake value tended to be high (median 19.3). The survival of patients without surgery demonstrated a significantly poor prognosis compared with those with surgery (P = 0.0096). Palliative chemotherapy was almost poor response in advanced pulmonary pleomorphic carcinoma. The response to gefitinib in a patient with EGFR mutation was small and transient. Conclusion: EGFR mutation was recognized in approximately 20% of patients with pulmonary pleomorphic carcinoma. It is necessary to investigate whether the use of a molecular targeting drug improves outcome for pulmonary pleomorphic carcinoma.