Light micrograph of a basal cell adenoma, a benign salivary gland tumour. There is a positive CD117 immunohistochemical stain on the tumour tissue. CD117 protein is found in the ductal cells of the tumour, which stain brown. A background blue haematoxylin stain shows the cells (basal cells and fibroblasts) lacking the CD117 protein. Magnification: 200x when printed at 10 cm.