The contributions of Santiago Ramón y Cajal to cancer research - 100 years on.

In 1906, Santiago Ramón y Cajal received the Nobel Prize for his detailed description of the nervous system. But Cajal (pronounced 'Cahal') worked in many fields and his contributions to cancer research have been overlooked, mainly because his observations were published in Spanish. As we near Cajal's Nobel Prize centennial celebration, we review his histological slides, original drawings and publications that are related to cancer. There is an impressive body of evidence that shows Cajal's interest in tumour biology.