CD44 and small cell lung carcinoma: Indeed, endogenous activation of Notch signaling regulates the switch between “non-neuroendocrine” SCLC cells displaying a high expression of HES1 effector, of Notch receptors, CD44 marker and of mesenchymal markers as well as sphere forming abilities, and “neuroendocrine” SCLC cells expressing high levels of DLL4 and the epithelial marker EpCam as well as a stochastic expression of Notch receptors.