Abdellah Hamed Khalil Ali

Aberrant DNA methylation of some tumor suppressor genes in lung cancers from workers with chromate exposure

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.

Methylation and expression profiles of MGMT gene in thymic epithelial tumors

OBJECTIVES A key challenge in diagnosis and treatment of thymic epithelial tumors (TET) is in improving our understanding of the genetic and epigenetic changes of these relatively rare tumors. METHODS Methylation specific PCR (MSP) and immunohistochemistry were applied to 66 TET to profile the methylation status of DNA repair gene O6-methylguanine DNA methyltransferase (MGMT) and its protein expression in TET to clarify the association between MGMT status and clinicopathological features, response to chemotherapy and overall survival. RESULTS MGMT methylation was significantly more frequent in thymic carcinoma than in thymoma (17/23, 74% versus 13/44, 29%; P<0.001). Loss of expression of MGMT protein was significantly more frequent in thymic carcinoma than in thymoma (20/23, 87% versus 10/44, 23%; P<0.0001). There is a significant correlation between of MGMT methylation and loss of its protein expression (P<0.0003). MGMT methylation and loss of expression were significantly more frequent in advanced thymic epithelial tumors (III/IV) than in early tumors (I/II). CONCLUSION MGMT methylation plays a soul role in development of TET, especially in thymic carcinoma. Therefore, translation of our results from basic molecular research to clinical practice may have important implication for considering MGMT methylation as a marker and a target of future therapies in TET.

Computed tomography lymphography by transbronchial injection of iopamidol to identify sentinel nodes in preoperative patients with non–small cell lung cancer: A pilot study

OBJECTIVE The objective of the present study was to assess the safety and feasibility of computed tomography lymphography by transbronchial injection of a water-soluble extracellular computed tomography contrast agent. METHODS From April 2010 to May 2011, patients with clinical stage I non-small cell lung cancer who were candidates for lobectomy were enrolled in the present study. An ultrathin bronchoscope was inserted to the target bronchus under the guidance of virtual bronchoscopic navigation images. Computed tomography images of the chest were obtained 0.5 and 5 minutes after 2 or 3 mL of iopamidol was injected through a microcatheter. Sentinel nodes were identified when the maximum computed tomography attenuation value of the lymph nodes on the postcontrast computed tomography images increased by 30 Hounsfield units or more compared with the precontrast images. Patients underwent lobectomy with standard lymph node dissection. RESULTS The ultrathin bronchoscope could access the targeted bronchus, and iopamidol was delivered into the peritumoral area in all 13 patients without any complications. Sentinel nodes were identified in 12 (92.3%) of the 13 patients. The average number of sentinel nodes was 1.5 (range, 1-2). Pathologic examination revealed metastatic lymph nodes in 2 patients. Metastatic nodes were included with the sentinel nodes. CONCLUSIONS Computed tomography lymphography by transbronchial injection of iopamidol was a safe and feasible method to identify the sentinel nodes in patients with clinical stage I non-small cell lung cancer.

5-Aminolevulinic acid-induced fluorescence diagnosis of pleural malignant tumor

BACKGROUND It is known that endogenously synthesized protoporphyrin IX (PpIX) following the administration of 5-aminolevulinic acid (5-ALA) is an effective photosensitizer for photodynamic diagnosis (PDD). We tested in vivo and in vitro susceptibility of human lung cancer and mesothelioma cells to photodynamic diagnosis (PDD) using 5-aminolevulinic acid (5-ALA) as a photosensitizer. METHODS Human lung cancer cell lines A549, Ma44-3, FT821 and human mesothelioma cell lines MSTO-211H, NCI-H290, Y-MESO-14 were incubated with 0.03% 5-ALA for 4 h. After incubation, protoporphyrin IX (PpIX) fluorescence was detected using a fluorescence microscope. Pleural carcinosis was induced in severe combined immunodeficiency disease mice using the previous cell lines to test the efficacy of PDD in vivo. The mice were sacrificed 4 h after oral administration of 400 mg/kg of 5-ALA. We counted the visible tumors under white light then fluorescence light. RESULTS In vitro, clear red fluorescence was observed in all cell lines. The mean fluorescence intensity was stronger in A549 and FT821 cells than Ma44-3 cells (165.59±26.49, 157.62±18.93 vs. 104.01±17.58). Also, MSTO-211H and NCI-H290 cells had stronger fluorescence intensity than Y-MESO-14 cells (142.51±26.85, 165.16±12.91 vs. 92.31±8.69). In vivo, the tumor detection rate of fluorescence diagnosis was 1.1-4.5 times higher than that of white light. The mean number of metastases detected by the PDD was significantly higher than that of white light for FT821 (p=0.004), Ma44-3 (p=0.006) and Y-MESO-14 cell lines (p=0.005), but not for A549, NCI-H290 and MSTO-211H cell lines. Small lesions were detected by fluorescence diagnosis even though the lesions were invisible macroscopically under white light. CONCLUSION Our results suggest the possibility of clinical application of fluorescence diagnosis with intrapleural malignant tumors.

Holter ECG monitoring of sympathovagal fluctuation during bronchoscopy.

The changes of autonomic nervous activity during bronchoscopic procedures are closely related to the development of cardiovascular complications. We aimed to evaluate the changes of autonomic nervous activity during bronchoscopic procedures using R‐R interval variability from electrocardiograms (ECGs) obtained during diagnostic bronchoscopy.

Monitoring of exhaled carbon monoxide and carbon dioxide during lung cancer operation

OBJECTIVE Carbon monoxide (CO) is expelled mainly via the lungs, so that exhaled carbon monoxide (Ex-CO) concentration reflects endogenous production. Recent reports have shown that Ex-CO levels are increased in critically ill patients and after anaesthesia and surgery. However, there has been no investigation of the changes in Ex-CO level during a lung operation. We continuously monitored Ex-CO and exhaled carbon dioxide (Ex-CO2) concentrations during surgery for lung cancer. METHODS Eighteen lung cancer patients who underwent elective lung cancer lobectomy were enrolled in this study. All patients were endotracheally intubated and ventilated under general anaesthesia. Ex-CO and Ex-CO2 concentrations were separately monitored and recorded continuously using two sets of Carbolyzer® breath analysers (Taiyo Inc., Osaka, Japan). RESULTS Ex-CO concentration increased rapidly in response to changes in body position from supine to decubitus and was significantly decreased when patients were once again lying back (supine 2). Upon restarting bilateral ventilation, Ex-CO concentration in the operated lung was significantly higher than that in the breathing lung. In the lateral decubitus position, Ex-CO2 concentration showed the same pattern of increase as seen for Ex-CO. In the operated lung, the Ex-CO2 concentrations changed significantly at clamping, declamping and supine 2. In the re-ventilated, operated lung, the Ex-CO2 concentration was significantly lower than in the breathing lung. In the breathing lung, the Ex-CO2 concentration did not exhibit any significant changes over the course of the operation. CONCLUSIONS When breathing was restarted, the Ex-CO level of the target lung was significantly higher than that of the breathing lung. The Ex-CO concentration was also affected by the surgical body position and this change was marked and transient.