At present, it was suggested that some cancers are decreased in schizo, such as prostate ca, lung ca but GI ca is increased in schizo. Conclusion is difficult to make from these findings becasue schizo have many factors different from normal population (e.g. smoking, antipsychotic tx, life-style). One paper said that male pt with antipsychotic tx has decreased risk of prostate ca (I think Yu-Li has good sample for such study). Another interesting finding is that schizo family member had decrease incidence of ca (Incidence of cancer among persons with schizophrenia and their relatives. Archives of General Psychiatry. 58(6):573-8, 2001).
Though D2 is not found in blood cell, D2 and other DA receptors are common in peripheral tissue that may involve ca pathogenesis.