The Web API's and the main website now display a list of any previous oncotree codes which represent the same class of tumor types as any returned oncotree code.
In the Web API, the model for tumorType contains an element named "history" which was a list of objects. Now the "history" element returns a list of Strings which contain any previous oncotree codes used for the same conceptual tumor types. (previous to the release queried)
In the website, if any previous oncotree codes exist for a node in the tree, then when the user hovers over the node, they will be displayed in the popup box. (labeled "previous codes:")