Noriko Yanagitani

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.

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.

Association of amino acid substitution polymorphisms in DNA repair genes TP53, POLI, REV1 and LIG4 with lung cancer risk.

Single nucleotide polymorphisms (SNPs) were searched for in 36 genes involved in diverse DNA repair pathways, and 50 nonsynonymous (associated with amino acid changes) SNPs identified were assessed for associations with lung cancer risk by a case‐control study consisting of 752 adenocarcinoma cases, 250 squamous cell carcinoma cases and 685 controls. An SNP, Arg72Pro, of the TP53 gene encoding a DNA damage response protein showed the strongest association with squamous cell carcinoma risk (OR Pro/Pro vs. Arg/Arg = 2.2), while 2 other SNPs, Phe257Ser of the REV gene encoding a translesion DNA polymerase and Ile658Val of the LIG4 gene encoding a DNA double‐strand break repair protein, also showed associations (OR Ser/Ser vs. Phe/Phe = 2.0 and OR Ile/Val vs. Ile/Ile = 0.4, respectively). An SNP, Thr706Ala, in the POLI gene encoding another translesion DNA polymerase was associated with adenocarcinoma and squamous cell carcinoma risk, particularly in individuals of ages < 61 years (OR Ala/Ala + Ala/Thr vs. Thr/Thr = 1.5 and 2.4, respectively). POLI is the human counterpart of PolI, a strong candidate for the Par2 (pulmonary adenoma resistance 2) gene responsible for adenoma/adenocarcinoma susceptibility in mice. The present results suggest that these 4 SNPs function as genetic factors underlying lung cancer susceptibility by modulating activities to maintain the genome integrity of each individual.

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)

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.

Association of the OGG1-Ser326Cys polymorphism with lung adenocarcinoma risk.

Adenocarcinoma (ADC) is the most frequent histological type of lung cancer and comprises the majority of lung cancers in non‐smokers. Thus, genetic factors responsible for ADC susceptibility need to be determined to establish efficient ways of preventing the disease. The OGG1 gene, encoding a glycosylase for 8‐hydroxyguanine, an oxidatively damaged promutagenic base, has the polymorphism Ser326Cys, and OGG1‐326Cys protein was indicated to have a lower ability to prevent mutagenesis than the OGG1‐326Ser protein. Case‐control studies to date suggest that the OGG1‐326Cys allele is associated with a higher risk for several types of cancers, including overall lung cancer. However, the contribution of this polymorphism to lung ADC risk is unclear. In the present study, the OGG1‐Ser326Cys polymorphism was assessed for association with lung ADC risk using a case‐control study of a Japanese population consisting of 1097 cases and 394 controls. Odds ratios (OR) of the 326Cys allele carriers increased in a dose‐dependent manner with allele number (P for the trend test = 0.04). The OR of homozygotes for the 326Cys allele was increased significantly when homozygotes for the 326Ser allele were used as a reference (OR = 1.5, 95% confidence interval [CI] = 1.0–2.1, P = 0.04). Furthermore, the overall OR for lung ADC of the Cys/Cys homozygotes out of a total of 1925 ADC patients and 3449 controls from six case‐control studies reported up to the present were 1.43 (95% CI = 1.11–1.84, P = 0.0045). These results indicate that OGG1‐326Cys functions as a risk allele for lung ADC development. (Cancer Sci 2006; 97: 724–728)

Evaluation of a whole-genome amplification method based on adaptor-ligation PCR of randomly sheared genomic DNA

High‐throughput genetic studies often require large quantities of DNA for a variety of analyses. Developing and assessing a whole‐genome amplification method is thus important, especially with the current desire for large‐scale genotyping in previously collected samples for which limited DNA is available. The method we have developed, called PRSG, is based on an adaptor‐ligation–mediated PCR of randomly sheared genomic DNA. An unbiased representation was evaluated by performing PCR on 2,607 exons of 367 genes, which are randomly distributed throughout the genome, on PRSG products of hundreds of individuals. An infrequent loss (<1%) of the exon sequence on the PRSG products was found. Out of 307 microsatellites on various chromosomes, 258 (84%) were amplified in both the PRSG product and an original DNA, whereas 49 (16%) microsatellites were lost only in the PRSG product. Array CGH analysis of 287 loci for measuring the relative gene copy number demonstrated that a low bias was detected. Moreover, this method was validated on 100–1,000 laser‐captured cells from paraffin‐embedded tissues. These data show that PRSG can provide a sufficient amount of genomic sequence for a variety of genetic analyses as well as for long‐term storage for future work.

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.

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).