Histological, immunohistochemical, and ultrastructural data accumulated in recent years have provided the basis for a more detailed classification of pancreatic cancer. This classification defines new tumour entities with distinct clinicopathologic and prognostic features. Unfortunately, morphologic and phenotypic studies of the more common ductal pancreatic cancer do not provide sufficient information to predict their clinical behaviour. The new field of investigation on genetic abnormalities in pancreatic cancer has not yet provided sufficient data to propose any genetically based classification or prognostic assessment. However, if there is some hope for prevention or cure, this will depend on efforts to clarify the molecular basis of the disease. These features could help in addressing epidemiological studies, in finding markers for diagnosis and prognosis, and might be helpful in devising completely new therapeutic approaches.