Conclusions
CBX3 and CRABP2 expression was markedly increased in lung cancer tissues and especially CRABP2 may be promising candidate genes in lung adenocarcinoma.
Methods
We enrolled 88 male patients (mean age, 61.2 years) with NSCLC. RNA-Seq was performed on 88 pairs of NSCLC tumor tissue and non-tumor tissue from 54 patients with adenocarcinoma and 34 patients with squamous cell carcinoma. Immunohistochemistry was performed to validate differential candidate gene expression in a different NSCLC group.
Results
RNA-Seq produced 25.41 × 10(6) (± 8.90 × 10(6)) reads in NSCLC tissues and 24.70×10(6) (± 4.70 × 10(6)) reads in normal lung tissues [mean (± standard deviation)]. Among the genes expressed in both tissues, 335 were upregulated and 728 were downregulated ≥ 2-fold (p < 0.001). Four upregulated genes - CBX3, GJB2, CRABP2, and DSP - not previously reported in lung cancer were studied further. Their altered expression was verified by immunohistochemistry in a different set of NSCLC tissues (n = 154). CBX3 was positive in 90.3% (139 cases) of the samples; GJB2, in 22.7% (35 cases); CRABP2, in 72.1% (111 cases); and DSP, in 17.5% (27 cases). The positive rate of CRABP2 was higher in adenocarcinoma than squamous cell carcinoma (p < 0.01). Conclusions: CBX3 and CRABP2 expression was markedly increased in lung cancer tissues and especially CRABP2 may be promising candidate genes in lung adenocarcinoma.