What distinguishes pancreas, liver, colon, kidney, prostate and gallbladder cancers?

Cure varies. Beyond the obvious differences in organ and cell type as well as the various treatment approaches, the most important patient difference is really the chance at cure. Early stage prostate and renal cell (kidney) cancers can be very curable. Even really early stage pancreatic cancers can be quite deadly.
Immunohistochemistry. When a biopsy is done, the pathologist looks at the tumor under the microscope. They can tell if it is cancer or not. Then they apply several markers which tells them where it could be originating from. For example, breast cancer is commonly ck7+ ck20-, while colon cancer is the opposite. In addition, also depends where the biopsy is taken from. Hope this helps.