Figure 1.

Heterogeneous expression of Notch1 in small cell lung cancer SCLC). (A) Hypothetical natural history of SLCL is depicted, focusing on Notch1 expression. Naïve SCLC cells prior to chemoradiotherapy are Notch1-negative, and show neuroendocrine differentiation. These cells show epithelial-mesenchymal transition (EMT), motility, and high proliferative potential. Furthermore, they are very sensitive to cytotoxic therapies. On the contrary, chemotherapy and radiotherapy can induce Notch expression that may be regulated by histone modification (18). Notch1-positive SCLC cells are non-neuroendocrine and lose some of their EMT characteristics. They reduce cell proliferation activity, but produce chemoresistance; (B) Notch1 expression in recurred SCLC tissue of an autopsy case of a patient who received repeated chemotherapy. The recurred tumor contains a few Notch1-positive cells. (Hemoatoxylin and eosin stain. Bar =50 µm).