Human endogenous retrovirus env genes: Potential blood biomarkers in lung cancer

Lung cancer, the leading cause of cancer mortality, needs urgent development of newly qualified diagnostic and therapeutic biomarkers. Recently, Human Endogenous Retroviruses (HERVs) have been introduced for cancer diagnosis. In this case-control study, we have collected blood samples from 60 lung cancer patients and 20 healthy controls. Quantitative gene expression analysis of various HERV env genes, including HERV-R, HERV-H, HERV-K, and HERV-P was performed by real-time PCR. Results indicate that expression of all four HERV env mRNAs is significantly increased in the blood of lung cancer patients than healthy controls (P-values<0.01). Furthermore, we have observed a positive and significant pairwise correlation between the expressions of four HERV env genes. The level of HERV env transcript in the blood of adenocarcinoma patients was generally much higher than squamous cell carcinoma (SCC) and small-cell lung cancer (SCLC) patients. Also, the expression of three HERV P, HERV H, and HERV K in the blood of lung cancer patients could significantly differentiate between adenocarcinoma and other types of lung cancer. In conclusion, these four HERV families could be considered as promising non-invasive blood-based biomarkers for prognosis, early detection, and monitoring of lung cancer.