Light micrograph of a breast cancerous tumour. The tumour, a type of breast cancer called invasive ductal carcinoma, is composed of small tubular structures (small blue circular spaces) which infiltrate into the breast fatty tissue (white) forming radial spicules creeping out along the edges of the tumour. This tumour was small enough (only a few millimetres) for the whole tumour to appear in the single microscopic field of view of this image. Haematoxylin and eosin stained tissue section. Magnification: 20x when printed at 10 centimetres.