The different sensitivities and specificities of neuroendocrine markers, such as chromogranin A (CgA), neural cell adhesion molecule 1 (CD56), synaptophysin (Syp) and neuron-specific enolase (NSE), may lead to significant variation in reported NSCLC-NED incidence and contradictory results about the prognosis of NSCLC-NED [9]. This evidence concerns the gene SYP and non-small cell lung carcinoma.