Motoi Aoe

Presence of Epidermal Growth Factor Receptor Gene T790M Mutation as a Minor Clone in Non–Small Cell Lung Cancer

The threonine-to-methionine substitution at amino acid position 790 (T790M) of the epidermal growth factor receptor (EGFR) gene has been reported in progressing lesions after gefitinib treatment in non-small cell lung cancer (NSCLC) that causes sensitive tumors to become resistant to gefitinib. Alternatively, the EGFR T790M mutation might be present in small fractions of tumor cells before drug treatment, and the tumor cells harboring the T790M mutation might be enriched during the proliferation after drug treatment. We developed a mutant-enriched PCR assay to detect small fractions of cells with T790M mutation and used this technique to detect mutations in 280 NSCLCs, including gefitinib-treated 95 cases. Although the direct sequencing detected only 1 T790M mutant case, the mutant-enriched PCR (confirmed to enrich one mutant out of 1 x 10(3) wild-type alleles) detected 9 additional cases among 280 cases. As linkage to clinicopathologic factors, the T790M mutation showed no bias for sex, smoking status, or histology but was significantly more frequent in advanced tumors (9 of 111 cases) than in early-stage tumors (1 of 169 cases; P = 0.0013). Among gefitinib-treated cases, gefitinib-sensitive mutations were found in 30 cases. The T790M mutation was present in 3 of 7 no-responders with the gefitinib-sensitive mutation and was not present in 19 responders (P = 0.014). Our results indicate that the T790M mutation is sometimes present in a minor population of tumor cells during the development of NSCLC and suggest that the detection of small fractions of T790M mutant alleles may be useful for predicting gefitinib resistance of NSCLCs with sensitive EGFR mutations.

Pulmonary function, postoperative pain, and serum cytokine level after lobectomy: a comparison of VATS and conventional procedure

BACKGROUND Although lobectomy by the video-assisted thoracic surgical (VATS) approach is assumed to be less invasive than lobectomy by the standard posterolateral thoracotomy (PLT) approach, it has not been scientifically proven. METHODS Twenty-two consecutive, nonrandomized patients, underwent either a VATS approach (n = 13) or a posterolateral thoracotomy approach (n = 9) to perform pulmonary lobectomy for peripheral lung cancers in clinical stage I. Pain and serum cytokines were measured until postoperative day (POD) 14. Pulmonary function tests were performed on POD 7 and POD 14. RESULTS Postoperative pain was significantly less in the VATS group on PODs 0, 1, 7, and 14. Recovery of pulmonary function was statistically better in the VATS group. Negative correlations between the recovery rates of pulmonary function and postoperative pain were observed on POD 7. The serum interleukin-6 level in the PLT group was significantly elevated on POD 0 compared with the VATS group (posterolateral thoracotomy: 21.6+/-24.3 pg/mL; VATS: 4.1+/-7.9 pg/mL, p = 0.03). CONCLUSIONS Lobectomy by the VATS approach generates less pain and cytokine production, and preserves better pulmonary function in the early postoperative phase.

Detection of EGFR Gene Mutation in Lung Cancer by Mutant-Enriched Polymerase Chain Reaction Assay

Purpose: Mutations in the epidermal growth factor receptor (EGFR) gene have been reported to be present in non–small cell lung cancer (NSCLC) and related to the responsiveness of tumors to EGFR tyrosine kinase inhibitors, suggesting its usefulness as a biomarker. Because clinical samples contain tumor and normal cells or genes, a highly sensitive assay for detecting mutation is critical for clinical applications. Experimental Design: The mutant-enriched PCR is a rapid and sensitive assay with selective restriction enzyme digestion. We developed the mutant-enriched PCR assay targeting exons 19 and 21 of EGFR and applied the developed assay to detect mutations in 108 cases of surgically resected specimens of NSCLCs, 18 samples of computed tomography (CT)–guided needle lung biopsies, and 20 samples of pleural fluid. In addition, results were then compared with those from direct sequencing and a nonenriched PCR assay. Results: The mutant-enriched PCR that was proved to enrich one mutant of 2 × 103 normal genes detected mutations in 37 cases of 108 resected tumors, seven samples of CT-guided lung biopsies, and seven samples of pleural fluid. Among mutant cases, four resected tumors, two CT-guided lung biopsies, and two pleural fluid were identified as additional mutant cases by the mutant-enriched PCR, which were considered normal based on nonenriched assays. Conclusions: Our results indicate that EGFR mutations are readily detectable by mutant-enriched PCR in various clinical samples. Thus, mutant-enriched PCR may provide a valuable method of potentially detecting a small fraction of mutant genes in heterogeneous specimens, indicating its possible use in clinical application for NSCLC.

Donor lung procurement: Assessment and operative technique

Given the relative scarcity of suitable donors and the widespread application of cardiac and pulmonary transplantation, it is imperative that a heart and two lungs be extracted from each donor. From increasing clinical experience and laboratory investigation in lung preservation, more flexible criteria for the assessment of potential lung donors are emerging. In this communication, we present our current criteria of donor lung suitability, and a simple and reliable technique of combined cardiopulmonary extraction that has provided suitable heart and lung grafts with excellent preservation, used in our last 150 donor organ procurements.

Mutational and Epigenetic Evidence for Independent Pathways for Lung Adenocarcinomas Arising in Smokers and Never Smokers

Genetic and epigenetic alterations are considered to play important roles in lung cancer. Recent studies showed that EGFR and K-RAS mutations exhibited a mutually exclusive pattern in adenocarcinoma of the lung, suggesting the presence of two independent oncogenic pathways. However, it is unknown how epigenetic alterations were involved in lung carcinogenesis mediated by EGFR or K-RAS mutation. In this study, we examined the relationship between genetic and epigenetic alterations in 164 cases of lung adenocarcinoma. Somatic mutations were determined by direct sequence of EGFR exons 18 to 21 and K-RAS codons 12 and 13. Methylation status of p16(INK4a), RASSF1A, APC, RARbeta, and CDH13, frequently methylated in lung cancer, was determined by methylation-specific PCR and the degree of methylation was defined as the methylation index. Multivariate analysis adjusted for age, sex, and smoking dose showed that the probability of having EGFR mutation was significantly lower among those with p16(INK4a) and CDH13 methylation than in those without [p16(INK4a): odds ratio (OR), 0.07; 95% confidence interval (95% CI), 0.02-0.33; CDH13: OR, 0.34; 95% CI, 0.15-0.77] and the methylation index was significantly lower in EGFR mutant cases than in wild type (OR, 0.70; 95% CI, 0.52-0.95). By contrast, K-RAS mutation was significantly higher in p16(INK4a) methylated cases than in unmethylated cases (OR, 4.93; 95% CI, 1.54-15.7) and the methylation index was higher in K-RAS mutant cases than in wild type with marginal significance (OR, 1.46; 95% CI, 0.95-2.25). Our results indicate the differences in the evolvement of epigenetic alterations between the EGFR- and K-RAS-mediated tumorigenesis and suggest the specific interaction of genetic and epigenetic changes in tumorigenesis of lung cancer.

The impact of epidermal growth factor receptor gene status on gefitinib-treated Japanese patients with non-small-cell lung cancer.

We investigated the relationships between genetic factors and clinical outcome in Japanese non‐small‐cell lung cancer (NSCLC) patients treated with gefitinib. Ninety‐eight NSCLC patients who had been treated with gefitinib, were screened for mutations in epidermal growth factor receptor (EGFR) exons 18–21, KRAS exon2, and polymorphisms including the CA simple sequence repeat in intron1 (CA‐SSR1) and single nucleotide polymorphisms in the promoter region (−216G/T and −191C/A), using a PCR‐based assay and direct sequencing. The EGFR copy number status was also evaluated using a fluorescence in situ hybridization assay. EGFR and KRAS mutations were found in 38 (38.8%) and 8 (8.2%) of the 98 patients, respectively. A high EGFR copy number status was identified in 31 (41.3%) of the 75 assessable patients. Drug‐sensitive EGFR mutations limited to exon19 deletions and L858R were independent predictive factors of a stronger sensitivity to gefitinib (p = 0.0002), the overall survival (OS) (p = 0.0036), and prolonged progression‐free survival (PFS) (p < 0.0001). The EGFR copy number status was not related to a sensitivity to gefitinib and prolonged OS and PFS. Regarding polymorphisms, patients with a short CA‐SSR1 showed a prolonged OS as compared with those with a long length in patients with a drug‐sensitive EGFR mutation, although this difference was not significant (p = 0.13). Thus, drug‐sensitive EGFR mutations predict a favorable clinical outcome and a high EGFR copy number may not be related to clinical benefits in gefitinib‐treated Japanese patients with NSCLC. Our findings also suggest that the CA‐SSR1 length may influence the clinical outcome in patients with a drug‐sensitive EGFR mutation.

Identification of proacrosin binding protein sp32 precursor as a human cancer/testis antigen

Serological expression cloning of antigens eliciting a humoral immune response to a syngeneic mouse sarcoma identified pem (mouse placenta and embryonic expression gene) as a new member of the cancer/testis family. To identify the human homologue of pem, mouse pem sequences and pem-related expressed sequence tags from human testis were used as PCR primers for amplification using human testis cDNA. However, rather than pem, another gene, designated OY-TES-1, was isolated and found to be the human homologue of proacrosin binding protein sp32 precursor originally identified in mouse, guinea pig, and pig. OY-TES-1 maps to chromosome 12p12-p13 and contains 10 exons. Southern blot analysis suggests the presence of two OY-TES-1-related genes in the human genome. In normal tissues, OY-TES-1 mRNA was expressed only in testis, whereas in malignant tissues, a variable proportion of a wide array of cancers, including bladder, breast, lung, liver, and colon cancers, expressed OY-TES-1. Serological survey of 362 cancer patients with a range of different cancers showed antibody to OY-TES-1 in 25 patients. No OY-TES-1 sera reactivity was found in 20 normal individuals. These findings indicate that OY-TES-1 is an additional member of the cancer/testis family of antigens and that OY-TES-1 is immunogenic in humans.

Living-donor lobar lung transplantation for various lung diseases

OBJECTIVE We report on our early experience in living-donor lobar lung transplantation for patients with various lung diseases including restrictive, obstructive, septic, and hypertensive lung diseases. METHODS From October 1998 to March 2002, living-donor lobar lung transplantation was performed in 14 patients with end-stage lung diseases. There were 11 female patients and 3 male patients, with ages ranging from 8 to 53 years, including 4 children and 10 adults. Diagnoses included primary pulmonary hypertension (n = 6), idiopathic interstitial pneumonia (n = 2), bronchiolitis obliterans (n = 2), bronchiectasis (n = 2), lymphangioleiomyomatosis (n = 1), and cystic fibrosis (n = 1). Bilateral living-donor lobar lung transplantation was performed in 13 patients and right single living-donor lobar lung transplantation was performed for a 10-year-old boy with primary pulmonary hypertension. RESULTS All the 14 patients are currently alive with a follow-up period of 4 to 45 months. Although their forced vital capacity (1327 +/- 78 mL, 50.2% of predicted) was limited at discharge, arterial oxygen tension on room air (98.5 +/- 1.8 mm Hg) and systolic pulmonary artery pressure (24.8 +/- 1.6 mm Hg) were excellent. Forced vital capacity improved gradually and reached 1894 +/- 99 mL, 67.4% of predicted, at 1 year. All donors have returned to their previous lifestyles. CONCLUSIONS Living-donor lobar lung transplantation can be applied to restrictive, obstructive, septic, and hypertensive lung diseases. This type of procedure can be an alternative to conventional cadaveric lung transplantation for both pediatric and adult patients who would die soon otherwise.

Thoracoscopic Operation for Secondary Pneumothorax Under Local and Epidural Anesthesia in High-Risk Patients

BACKGROUND Video-assisted thoracic operations usually require single-lung ventilation under general anesthesia. However, for high-risk patients with other underlying pulmonary diseases, one has to consider risks of general anesthesia itself. METHODS Four high-risk patients (4 men; mean age, 73 years) with intractable secondary pneumothorax and other underlying pulmonary diseases were treated by video-assisted thoracic operations under local and epidural anesthesia. Absorbable polyglycolic acid sheets and fibrin glue were used to control the air leakage. RESULTS The mean duration of the procedure was 108 minutes. Pain and cough reflex were well controlled, and spontaneous breathing and hemodynamics were well maintained during the operation. The mean duration of the postoperative chest drainage was 5 days. No significant postoperative complication was encountered. No pneumothorax had recurred at a mean follow-up of 16 months. CONCLUSIONS Video-assisted thoracic operations can be performed safely under local and epidural anesthesia for the treatment of intractable secondary pneumothorax in high-risk patients. The air leakage can be controlled with the use of polyglycolic acid sheets and fibrin glue without bullectomy.

Aberrant promoter methylation of human DAB2 interactive protein (hDAB2IP) gene in lung cancers

The human DOC‐2/DAB2 interactive protein gene (hDAB2IP) is a novel member of the Ras GTPase‐activating gene family that is known to act as a tumor suppressor gene and is inactivated by methylation in prostate and breast cancers. We established previously a methylation‐specific PCR (MSP) for the promoter region (m2a and m2b regions) of hDAB2IP and examined hDAB2IP methylation status in breast cancers. We analyzed the methylation and expression status of hDAB2IP in lung cancers. The methylation status of hDAB2IP was examined in lung cancer cell lines using bisulfite sequencing and MSP. Expression was examined using conventional and real‐time RT‐PCR, and methylation was found to be inversely correlated with expression, confirming that the MSP can also be used to examine hDAB2IP methylation status in lung cancers. Aberrant methylation was detected at the m2a region in 19 of 47 lung cancer cell lines (40%) and 26 of 70 primary tumors (37%) and at the m2b in 16 lines (34%) and 25 of 70 tumors (36%). Gene expression was restored in methylated cell lines supplemented with 5‐aza‐2′‐deoxycytidine, confirming that methylation was responsible for downregulation. We also examined the relationship between hDAB2IP methylation and clinico‐pathological features of the lung cancers and found that hDAB2IP methylation was associated with advanced disease stage. Our results demonstrate that hDAB2IP methylation is frequently present in lung cancers and plays a key role in hDAB2IP silencing. hDAB2IP methylation could be used as a biomarker for disease stage, reflecting the degree of clinico‐pathological malignancy of lung cancer.