A review of porphyria and cancer and the missing link with human exposure to hexachlorobenzene.

A literature review shows that porphyria cutanea tarda (PCT), and possibly acute intermittent porphyria also, tend to occur more often than expected among cases of primary liver cancer, especially when cirrhosis is present. Lymphomas and PCT may be related also, although this is less well documented. Furthermore, there is an interesting report on a case of PCT, sarcoma and probable exposure to 2,3,7,8-tetrachlorodibenzo-para-dioxin. Exposure to hexachlorobenzene (HCB) as a cause of cancer in humans does not seem to have been reported, however, but exposure to this compound and other chlorinated aromatics should be included in future observations of PCT and cancer. The possibilities for good epidemiological studies of HCB exposure in relation to cancer and other effects seem to be limited although some guidelines can be given.