الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Lung cancer is the leading cause of cancer related deaths worldwide. It is the 4th or 5th most common type of cancer in Egypt (whether Upper or Lower Egypt) in 2007.
Many risk factors are contributed to the pathogenesis of lung cancer. The most important risk factor is smoking. Smoking increases the risk of lung cancer 5 to 10 fold with a dose–response relationship. Other environmental risk factors such as exposures to radon, asbestos, diesel, and ionizing radiation also play a role in increasing the risk of lung cancer.
Patients can live with lung cancer for many years before its symptoms are manifested. Early lung cancer is mainly asymptomatic and many patients are not alerted by obvious physical changes. Lung cancer commonly presents with cough and dyspnea, other clinical manifestations include hemoptysis, finger clubbing, anemia, signs and symptoms of compression of the nearby vital organs or structures, paraneoplastic syndrome and metastasis.
Lung cancer is mainly classified into two main types; NSCLC and SCLC. Non-Small cell lung cancer is the most common type; it could be further classified into: adenocarcinoma, squamous cell carcinoma, large cell (undifferentiated) carcinoma, bronchoalveolar carcinoma (adenocarcinoma in situ), mucoepidermoid, adenocystic, adenosquamous and carcinoid.
Lung cancer is diagnosed by sputum cytology, chest x-ray, CT chest, bronchoscopy, BAL cytology, pleural fluid cytological analysis if malignant effusion is present and finally tissue biopsy. A lot of cases are diagnosed late in the disease as the symptoms are not always manifested early; this leads to the decrease in the 5 year survival rate for the patient.
Our present study aimed at evaluating of SHOX2 gene methylation level in BAL and its role in the diagnosis of lung cancer. Forty subjects were enrolled in this study; thirty served as cases who presented with a suspicious lung mass by CT and later proved to be malignant by tissue biopsy. Ten subjects served as controls, they had no lung cancer and were cytology negative for malignant cells.
All cases were subjected to full history taking and complete clinical examination, laboratory investigations were done including liver function tests (ALT and AST), renal function tests (urea and creatinine) and CBC. Radiological investigations such as chest x-ray or CT of the chest were done. Bronchoscopy was performed on all patients and BAL samples were collected for cytological analysis and DNA extraction. Cytology for BAL was done to confirm or exclude malignancy. The diagnosis of lung cancer was confirmed by cytology and/or histopathology from biopsy or surgically resected specimen. DNA was extracted from BAL. Extracted DNA was then digested by restriction enzymes to estimate methylation levels of SHOX2 gene. Percentage of SHOX2 gene methylation was measured by EpiTect Methyl II PCR Assay, where real time PCR was used.
In our study, the mean age of patients with lung cancer was 60.5 years, while that of controls was 54 years, this indicated the prevalence of lung cancer in the old age group. Also the prevalence of male gender among cases indicated that lung cancer is more common in male patients.
Smoking status in our study was of statistical significance, where the majority of controls were nonsmokers (70%) while the majority of the cases (63%) smoked cigarettes.
Lung cancer is the leading cause of cancer related deaths worldwide. It is the 4th or 5th most common type of cancer in Egypt (whether Upper or Lower Egypt) in 2007.
Many risk factors are contributed to the pathogenesis of lung cancer. The most important risk factor is smoking. Smoking increases the risk of lung cancer 5 to 10 fold with a dose–response relationship. Other environmental risk factors such as exposures to radon, asbestos, diesel, and ionizing radiation also play a role in increasing the risk of lung cancer.
Patients can live with lung cancer for many years before its symptoms are manifested. Early lung cancer is mainly asymptomatic and many patients are not alerted by obvious physical changes. Lung cancer commonly presents with cough and dyspnea, other clinical manifestations include hemoptysis, finger clubbing, anemia, signs and symptoms of compression of the nearby vital organs or structures, paraneoplastic syndrome and metastasis.
Lung cancer is mainly classified into two main types; NSCLC and SCLC. Non-Small cell lung cancer is the most common type; it could be further classified into: adenocarcinoma, squamous cell carcinoma, large cell (undifferentiated) carcinoma, bronchoalveolar carcinoma (adenocarcinoma in situ), mucoepidermoid, adenocystic, adenosquamous and carcinoid.
Lung cancer is diagnosed by sputum cytology, chest x-ray, CT chest, bronchoscopy, BAL cytology, pleural fluid cytological analysis if malignant effusion is present and finally tissue biopsy. A lot of cases are diagnosed late in the disease as the symptoms are not always manifested early; this leads to the decrease in the 5 year survival rate for the patient.
Our present study aimed at evaluating of SHOX2 gene methylation level in BAL and its role in the diagnosis of lung cancer. Forty subjects were enrolled in this study; thirty served as cases who presented with a suspicious lung mass by CT and later proved to be malignant by tissue biopsy. Ten subjects served as controls, they had no lung cancer and were cytology negative for malignant cells.
All cases were subjected to full history taking and complete clinical examination, laboratory investigations were done including liver function tests (ALT and AST), renal function tests (urea and creatinine) and CBC. Radiological investigations such as chest x-ray or CT of the chest were done. Bronchoscopy was performed on all patients and BAL samples were collected for cytological analysis and DNA extraction. Cytology for BAL was done to confirm or exclude malignancy. The diagnosis of lung cancer was confirmed by cytology and/or histopathology from biopsy or surgically resected specimen. DNA was extracted from BAL. Extracted DNA was then digested by restriction enzymes to estimate methylation levels of SHOX2 gene. Percentage of SHOX2 gene methylation was measured by EpiTect Methyl II PCR Assay, where real time PCR was used.
In our study, the mean age of patients with lung cancer was 60.5 years, while that of controls was 54 years, this indicated the prevalence of lung cancer in the old age group. Also the prevalence of male gender among cases indicated that lung cancer is more common in male patients.
Smoking status in our study was of statistical significance, where the majority of controls were nonsmokers (70%) while the majority of the cases (63%) smoked cigarettes.
Cytology results of BAL obtained by bronchoscopy were negative for malignant cells in 26.7% of cases but were proven to be positive for malignancy by histopathology from lung tissue biopsy. The rest of the cytological analysis of cases was positive for malignant cells (73.3%).