Patients and specimens
In the current study, a total of 173 participants were recruited from The First Affiliated Hospital of Xinxiang Medical University, which included 108 lung cancer patients and 65 healthy controls. The inclusion criteria of lung cancer patients was no previous history of cancer-related diseases and did not receive radiotherapy or chemotherapy prior to research. The healthy control individuals were without tumor-associated lesions before the study. Total of 5ml peripheral blood samples from lung cancer patients and healthy controls were obtained and centrifuged and then stored at -80℃ for further experiments. This study was approved by the Ethical Committee of the hospital and all enrolled patients provided written informed consents prior to sample collection. The clinicopatholgical features for these patients were listed in Table 1.
Table 1. Relationship between CHD5 expression and clinical features of lung cancer patients
Features
|
All cases
|
CHD5 expression
|
P Value
|
low
|
high
|
Total
|
108
|
52
|
56
|
|
Age (Years)
|
|
|
|
0.332
|
≤ 60
|
53
|
23
|
30
|
> 60
|
55
|
29
|
26
|
Gender
|
|
|
|
0.001
|
Female
|
48
|
32
|
16
|
Male
|
60
|
20
|
40
|
Tumor size (cm)
|
|
|
|
0.316
|
≤5
|
49
|
21
|
28
|
>5
|
59
|
31
|
28
|
Smoking history
|
|
|
|
0.000
|
≤10
|
51
|
35
|
16
|
>10
|
57
|
17
|
40
|
TNM stage
|
|
|
|
0.020
|
I - II
|
56
|
33
|
23
|
III - IV
|
52
|
19
|
33
|
RNA extraction and quantitative real-time polymerase chain reaction (qRT-PCR)
Total RNA was extracted from the serum samples using the Trizol reagent (Invitrogen, Carlsbad, CA, USA) following the manufacturer's instructions and the purity of RNAs was measured using a NanoDrop ND-1000 (NanoDrop Technologies, Wilmington, DE, USA). After purification cDNA was synthesized using the First-Strand cDNA Synthesis Kit (ReverTra Ace-a, FSK-100, Toyobo, Osaka, Japan) according to the manufacture’s protocol. The real-time PCR was conducted using the 7300 Real-Time PCR System (Applied Biosystems, USA). GAPDH was used as the internal control and each sample was examined in triplicate.
Statistical analysis
In the study, SPSS 21.0 (SPSS Inc., Chicago, IL, USA) software was used to perform all the statistical analyses and GraphPad Prism 5.0 (GraphPad Software, Inc., La Jolla, CA, USA) software was used to generate all the graphs. The Student’s t test was used to assess the difference of CHD5 expression level in lung cancer samples and healthy control samples. The relationship between CHD5 expression and clinicopathological characteristics of lung cancer patients was assessed by Chi-square test. The ROC curve was established to explore the diagnostic value of CHD5 in lung cancer patients. P value less than 0.05 was considered statistically significant.