Sarcomatoid carcinoma cells were partially positive for AE1/AE3 and strongly positive for vimentin (Fig. 3C), whereas all the tumor cells were negative for neuroendocrine markers and other mesenchymal markers, such as desmin, SMA, myglobin, mygenin, S-100, DOG-1, CD34, CD117, CD15, CD30, and CD20. The gene discussed is KIT; the disease is neoplasm.