Methylated APC and RASSF1A in multiple specimens contribute to the differential diagnosis of patients with undetermined solitary pulmonary nodules.
BACKGROUND
Inactivation of tumor-suppressor gene (TSG) by promoter hypermethylation has been reported in many tumor types, including lung cancer. This study was designed to determine the methylated APC and RASSF1A genes in tumor tissue, serum and plasma of patients with early stage lung cancer.


METHODS
Eighty-nine patients with undetermined solitary pulmonary nodules detected upon CT-scan were recruited in this study. DNA samples were extracted from biopsy tissues, serum and plasma and QMSP of APC and RASSF1A was carried out after bisulfite conversion. The 89 patients consist of 58 stage I lung cancer patients and 31 benign lung disease according to pathological report. Twenty-six cancer patients had matched biopsy tumor tissue, serum and plasma samples.


RESULTS
The methylation rates of APC and RASSF1A were 59.0% and 66.1% in biopsy tissues, 42.5% and 52.5% in serum, and 24.1% and 43.1% in plasma of cancer patients. For RASSF1A, different samples all showed a significant difference between cancer group and benign group (P<0.05). However, APC gene only explored the P value less than 0.05 in plasma result. Towards the 26 lung cancer patients with three matched samples, methylation rate in each sample type was more than 50.0% and displayed no difference.


CONCLUSIONS
Evaluation of APC and RASSF1A promoter methylation by using QMSP appears to be very useful for the differential diagnosis of patients with undetermined solitary pulmonary nodules. Our results also suggested that plasma might be the best sample for clinical detection of early stage lung.
1 Department of Laboratory Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China ; 2 National Key Clinical, Department of Laboratory Medicine, Nanjing 210029, China ; 3 Department of Radiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China ; 4 Department of Thoracic and Cardiovascular Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
Li
L
Gao
1 Department of Laboratory Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China ; 2 National Key Clinical, Department of Laboratory Medicine, Nanjing 210029, China ; 3 Department of Radiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China ; 4 Department of Thoracic and Cardiovascular Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
Erfu
E
Xie
1 Department of Laboratory Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China ; 2 National Key Clinical, Department of Laboratory Medicine, Nanjing 210029, China ; 3 Department of Radiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China ; 4 Department of Thoracic and Cardiovascular Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
Tongfu
T
Yu
1 Department of Laboratory Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China ; 2 National Key Clinical, Department of Laboratory Medicine, Nanjing 210029, China ; 3 Department of Radiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China ; 4 Department of Thoracic and Cardiovascular Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
Dan
D
Chen
1 Department of Laboratory Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China ; 2 National Key Clinical, Department of Laboratory Medicine, Nanjing 210029, China ; 3 Department of Radiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China ; 4 Department of Thoracic and Cardiovascular Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
Lixia
L
Zhang
1 Department of Laboratory Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China ; 2 National Key Clinical, Department of Laboratory Medicine, Nanjing 210029, China ; 3 Department of Radiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China ; 4 Department of Thoracic and Cardiovascular Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
Bingfeng
B
Zhang
1 Department of Laboratory Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China ; 2 National Key Clinical, Department of Laboratory Medicine, Nanjing 210029, China ; 3 Department of Radiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China ; 4 Department of Thoracic and Cardiovascular Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
Fang
F
Wang
1 Department of Laboratory Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China ; 2 National Key Clinical, Department of Laboratory Medicine, Nanjing 210029, China ; 3 Department of Radiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China ; 4 Department of Thoracic and Cardiovascular Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
Jian
J
Xu
1 Department of Laboratory Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China ; 2 National Key Clinical, Department of Laboratory Medicine, Nanjing 210029, China ; 3 Department of Radiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China ; 4 Department of Thoracic and Cardiovascular Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
Peijun
P
Huang
1 Department of Laboratory Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China ; 2 National Key Clinical, Department of Laboratory Medicine, Nanjing 210029, China ; 3 Department of Radiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China ; 4 Department of Thoracic and Cardiovascular Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
Xisheng
X
Liu
1 Department of Laboratory Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China ; 2 National Key Clinical, Department of Laboratory Medicine, Nanjing 210029, China ; 3 Department of Radiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China ; 4 Department of Thoracic and Cardiovascular Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
Bingliang
B
Fang
1 Department of Laboratory Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China ; 2 National Key Clinical, Department of Laboratory Medicine, Nanjing 210029, China ; 3 Department of Radiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China ; 4 Department of Thoracic and Cardiovascular Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
Shiyang
S
Pan
APC; Lung cancer; RASSF1A; quantitative methylation-specific PCR