Hiroshi Watanabe

PURPOSE: This study was undertaken to investigate the efficacy and the feasibility of gefitinib for chemotherapy-naïve patients with advanced non-small-cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR) mutations. PATIENTS AND METHODS: The EGFR gene status in various tumor samples obtained from chemotherapy-naïve advanced NSCLC patients was examined by DNA sequencing of EGFR exons 18 to 23. Patients harboring EGFR mutations received gefitinib (250 mg/d) alone. The response rate, progression-free survival (PFS), and toxicity profile were assessed prospectively. RESULTS: Between June 2004 and October 2005, 75 patients were examined for the EGFR status, and 25 patients (33%) harbored EGFR mutations. EGFR mutations were significantly frequent in females (P < .01) and never or light smokers (P < .001). Sixteen patients with EGFR mutations were enrolled onto the study. The overall response rate in these patients was 75% (95% CI, 54% to 96%), and the disease control rate was 88% (95% CI, 71% to 100%). The median PFS time of these patients was 9.7 months (95% CI, 7.4 to 9.9 months). No life-threatening toxicity was observed. CONCLUSION: Treatment with gefitinib alone for chemotherapy-naïve NSCLC patients with EGFR mutations could achieve a high efficacy with acceptable toxicity. To assess the proper timing of gefitinib in such patients, a subsequent randomized trial comparing gefitinib with standard chemotherapy is warranted.

Brugada syndrome is a genetic disease associated with sudden cardiac death that is characterized by ventricular fibrillation and right precordial ST segment elevation on ECG. Loss-of-function mutations in SCN5A, which encodes the predominant cardiac sodium channel alpha subunit NaV1.5, can cause Brugada syndrome and cardiac conduction disease. However, SCN5A mutations are not detected in the majority of patients with these syndromes, suggesting that other genes can cause or modify presentation of these disorders. Here, we investigated SCN1B, which encodes the function-modifying sodium channel beta1 subunit, in 282 probands with Brugada syndrome and in 44 patients with conduction disease, none of whom had SCN5A mutations. We identified 3 mutations segregating with arrhythmia in 3 kindreds. Two of these mutations were located in a newly described alternately processed transcript, beta1B. Both the canonical and alternately processed transcripts were expressed in the human heart and were expressed to a greater degree in Purkinje fibers than in heart muscle, consistent with the clinical presentation of conduction disease. Sodium current was lower when NaV1.5 was coexpressed with mutant beta1 or beta1B subunits than when it was coexpressed with WT subunits. These findings implicate SCN1B as a disease gene for human arrhythmia susceptibility.

BACKGROUND: The metabolic syndrome consists of a cluster of atherosclerotic risk factors, many of which also have been implicated in the genesis of atrial fibrillation (AF). However, the precise role of the metabolic syndrome in the development of AF is unknown. METHODS AND RESULTS: This prospective, community-based, observational cohort study was based on an annual health check-up program in Japan. We studied 28 449 participants without baseline AF. We used 2 different criteria for the metabolic syndrome--the guidelines of the National Cholesterol Education Program Third Adult Treatment Panel (NCEP-ATP III) and those of the American Heart Association/National Heart, Lung, and Blood Institute (AHA/NHLBI)--to study the risk of development of new-onset AF. The metabolic syndrome was present in 3716 subjects (13%) and 4544 subjects (16%) using the NCEP-ATP III and AHA/NHLBI definitions, respectively. During a mean follow-up of 4.5 years, AF developed in 265 subjects (105 women). Among the metabolic syndrome components, obesity (age- and sex-adjusted hazard ratio [HR], 1.64), elevated blood pressure (HR, 1.69), low high-density lipoprotein cholesterol (HR, 1.52), and impaired fasting glucose [corrected] (HR, 1.44 [NCEP-ATP III] and 1.35 [AHA/NHLBI]) showed an increased risk for AF. The association between the metabolic syndrome and AF remained significant in subjects without treated hypertension or diabetes by the NCEP-ATP III definition (HR, 1.78) but not by the AHA/NHLBI definition (HR, 1.28). CONCLUSIONS: The metabolic syndrome was associated with increased risk of AF. The metabolic derangements of the syndrome may be important in the pathogenesis of AF.