In this paper we present a collaborative consultative knowledge system for cancer diseases. The «Worldwide Collaborative Consultative Knowledge System» aims to meet four goals. The first one is to be a tool which allows experts in a particular domain to develop a common knowledge base in a collaborative way. A second goal is the support of multiple knowledge bases. Each knowledge base is constructed to be used in a consultative way either from simple users or from experts of the domain offering high quality consultation services. In this paper we focus in cancer diseases. The third goal has to do with the usability and flexibility of our system. Basically that means less restrictions and more abstraction. The final goal is to be multilingual tool by using a translator subsystem that could auto-translate user’s input and output into the language of user’s choice.