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Table 1 Baseline characteristics of study population

From: Epigenetic imprinting alterations as effective diagnostic biomarkers for early-stage lung cancer and small pulmonary nodules

  Model building set
(n = 246)
Model testing set
(n = 30)
Model validation set
(n = 155)
Normala Benign Malignant p Benign Malignant p Benign Malignant p
(n = 21) (n = 51) (n = 174) (n = 9) (n = 21) (n = 38) (n = 117)
Age     < 0.001    0.700    0.001
 Median 52 57 62   62 62   61 64  
 IQR 45–57 49–63 53–67   49–77 56–66   52–63 58–71  
Sex (%)     0.467    0.640    0.692
 Male 14 (66.7%) 28 (54.9%) 111 (63.8%)   6 (66.7%) 17 (81.0%)   25 (65.8%) 81 (69.2%)  
 Female 7 (33.3%) 23 (45.1%) 63 (36.2%)   3 (33.3%) 4 (19.0%)   13 (34.2%) 36 (30.8%)  
Sample type
 Surgically resected tissue specimen 21 51 174        
 Small biopsy specimen      9 21   38 36  
 Cytology specimen          81  
Histologic characteristics no
 Normal 21          
 PC   10         
 PSP   13         
 TB   10    2    7   
 COP   10       2   
 PIP   3         
 Non-TB infections      3    8   
 Inflammation   3    4    19   
 Granuloma   2       1   
 Hamartoma         1   
 AdC    94    9    61  
 SqCC    76    6    28  
 AdSqLC    2       2  
 LCC    1        
 SCLC       5    23  
 Carcinoma of unknown primary    1    1    3  
Nodule size     e    e    e
 < 0.8 cm    7   2    10 1  
 ≥ 0.8–2.0 cm   3 35   1 1   2 20  
 > 2.0–3.0 cm    48    9   3 32  
 > 3.0–5.0 cm   1 52    4   4 42  
 > 5.0 cm    28    6    18  
 Unclear LDCT featuresb 21 44    5    12 1  
 Not specifiedc   3 4   1 1   7 3  
Smoking statusd (%)     0.001    e    0.006
 Current smoker 3 (14.3%) 3 (5.9%) 56 (32.2%)   1 (11.1%) 6 (28.6%)   7 (18.4%) 48 (41.0%)  
 Former smoker 1 (4.8%) 1 (2.0%) 11 (6.3%)   0 (0.0%) 3 (14.3%)   2 (5.3%) 11 (9.4%)  
 Non-smoker 15 (71.4%) 40 (78.4%) 90 (51.7%)   1 (11.1%) 8 (38.1%)   16 (42.1%) 40 (34.2%)  
 Not specified 2 (9.5%) 7 (13.7%) 17 (9.8%)   7 (77.8%) 4 (19.0%)   13 (34.2%) 18 (15.4%)  
  1. PC, Pulmonary cryptococcosis. PSP, pulmonary sclerosing pneumocytoma. TB, pulmonary tuberculosis. COP, cryptogenic organizing pneumonia. PIP, pulmonary inflammatory pseudotumor. AdC, adenocarcinoma. SqCC, squamous cell carcinoma. AdSqLC, adenosquamous lung carcinoma. LCC, large cell carcinoma. SCLC, small cell lung cancer
  2. aNormal tissue specimens were resected adjacent to the benign lesions
  3. bNo typical nodule under LDCT
  4. cNodule sizes not recorded by doctors
  5. dCases classified as current or former smokers were combined into a single category prior to analysis to comply with the statistical test requirements
  6. eNo analysis proceeded since data transformations applied failed to meet the statistical test requirements