No abstract

Our previous studies revealed a variety of genetic changes in lung cancers from chromate-exposed workers (chromate lung cancer). In the present study, we examined epigenetic changes in chromate lung cancers. Nested-methylation-specific PCR was employed in studying the methylation of CpG islands in the APC, MGMT, hMLH1 genes in 36 chromate lung cancers and 25 nonchromate lung cancers. Methylation in chromate lung cancers was detected at 86% for APC, 20% for MGMT, and 28% for hMLH1. Whereas, it occurred at lower frequencies in nonchromate lung cancers, particularly in APC (44%) and hMLH1 (0%) genes. Our previous study showed that methylation of p16 gene in chromate lung cancer and nonchromate lung cancer was 33% and 26%, respectively. The mean methylation index (MI), a reflection of the overall methylation status, was significantly higher in chromate lung cancers than nonchromate lung cancers (0.41 vs. 0.21, P=0.001). Methylation of multiple genes (particularly hMLH1, p16, and APC genes) had experienced more than 15 yr of chromate exposure in chromate lung cancer (MI: <15 yr; 0.19, ≥ 15 yr, 0.42). There is a significant correlation of p16 and hMLH1 methylation with the expressional decrease or loss of the corresponding gene products (P=0.037 and 0.024) respectively, and an inverse correlation between APC and MGMT methylation (P = 0.014). This study provides a novel evidence for the chromium carcinogenesis that chromate lung cancer is linked to the progressive methylation of some tumor suppressor genes, which may be related to genomic instability.

<b><i>Background:</i></b> Transbronchial biopsy is a safe diagnostic approach for patients with peripheral pulmonary lesions; however, the diagnostic yield is low. <b><i>Objectives:</i></b> This study was conducted to evaluate the feasibility and diagnostic yield of transbronchial biopsy using the combination of an ultrathin bronchoscope, virtual bronchoscopic navigation (VBN), and cone-beam computed tomography (CBCT). <b><i>Methods:</i></b> Patients with peripheral pulmonary lesions, no &#x3e;30 mm, with the responsible bronchus, were prospectively included. An ultrathin bronchoscope and biopsy forceps were advanced to the target bronchus under VBN, 2D-fluoroscopy, and CBCT. We categorized the CBCT findings before biopsy into 3 types according to positions of the target lesion and forceps (CBCT target-forceps sign). In type A, the forceps reached the inside of the target lesion. In type C, the forceps could not reach the lesion. When the CBCT findings could not be categorized into either type A or C, the sign was categorized as type B. <b><i>Results:</i></b> Although the target lesions were invisible by conventional C-arm fluoroscopy in 29 patients, CBCT visualized all 40 lesions. The overall diagnostic yield was 90.0%, and diagnostic yields for malignant and benign lesions were 92.0 and 86.7%, respectively. Diagnostic yields for CBCT target-forceps sign types A, B, and C were 100, 75.0, and 0%, respectively. Four undiagnosed patients proceeded to other diagnostic procedures based on the CBCT target-forceps sign (type B: <i>n</i> = 2, type C: <i>n</i> = 2) and were correctly diagnosed without delay. <b><i>Conclusions:</i></b> Transbronchial biopsy using an ultrathin bronchoscope guided by CBCT and VBN showed a very high yield in the diagnosis of pulmonary nodules.

We could prospectively show that our method was suitable to perform WWR with a sufficient margin for small GGO lesions of <20 mm. Moreover, we reconfirmed that the advantages of our method were safety, permitting flexibility in scheduling operations and a high ability to deal with multiple lesions. Additionally, our method became a minimally invasive and mature technique by using a new VBN system.

FDG-PET/CT is a useful tool that has high capability to detect recurrences in asymptomatic NSCLC patients after a potentially curative operation. However, a large-scale multi-institutional randomized control trial may be needed to ascertain the benefit of surveillance with FDG-PET/CT.