Abstract B4: A 'DNA replication stress' gene signature associated with a poor prognosis in early non-small cell lung cancer

The conventional clinical staging classification is not sufficient to predict the survival of patients who suffer from early lung cancer. Additional prognostic factors are then needed to better forecast their outcome. Since perturbation of the genome replication i.e. the so-called “replicative stress” is admitted to contribute to neoplasia from its early stages, we hypothesized that genes involved in such process may therefore represent a still under-explored source of such biomarkers. We specifically assessed in primary tumors and adjacent normal tissues from a series of 93 patients suffering from early- or mid-stage non-small cell lung adenocarcinoma the expression (RT-qPCR) of 77 “DNA replication” genes involved in either initiation/licensing at the 50,000 replication origins dispersed along the genome, elongation of DNA chains onto damaged or undamaged DNA, maintenance of stalled DNA replication forks or intra-S phase DNA damage processing and signaling. A 4-gene signature separated patients to high-risk and low-risk subgroups with significantly different survival. This prognostic effect was independent on age, sex, treatment, stage classification and expression of proliferation markers. We propose that a “cancer replisome” signature could be a predictor of the cancer survival and might also help understanding the molecular mechanisms underlying tumor progression in lung cancer patients.