Molecular detection of neuron-specific ELAV-like-positive cells in the peripheral blood of patients with small-cell lung cancer

Background: n-ELAV (neuronal-Embryonic Lethal, Abnormal Vision)-like genes belong to a family codifying for onconeural RNA-binding proteins. Anti-Hu-antibodies (anti-Hu-Ab) are typically associated with paraneoplastic encephalomyelitis/sensory neuropathy (PEM/PSN), and low titres of anti-Hu-Ab, were found in newly diagnosed Small Cell Lung Cancer (SCLC). The aim of this study is to develop a sensitive and quantitative molecular real-time PCR assay to detect SCLC cells in peripheral blood (PB) through nELAV-like transcripts quantification. Methods: Peripheral blood samples from 25 SCLC untreated patients and 12 healthy blood donors were investigated by real-time PCR. mRNA levels for HuB (ELAV2), HuC (ELAV3) and HuD (ELAV4) were measured in peripheral blood samples with an absolute quantification method using plasmid dilutions as calibration curves. Results: A statistically significant increase in mRNA expression level was detected for HuB and HuD in SCLC patients as compared with samples from healthy blood donors. After establishing cut off values based on the level of expression in control samples, 28% of the SCLC samples were positive for HuD expression. Overall 60% of the SCLC displayed increased level of HuD or HuB transcripts. Conclusion: Our preliminary results suggest that neuron-ELAV mRNA are detectable in peripheral blood of SCLC patients using real-time quantitative PCR.