Researchers at Johns Hopkins University were studying a compound, called PhIP (2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine), which forms when meat is cooked at very high temperatures. They say the new research may help explain the more general link between prostate cancer and people who eat meat.
PhIP acts as both an initiator and promoter of prostate cancer in rats, according to the study. Previous research in rats has shown that PhIP causes early prostate cancer lesions only in the front of the organ called the ventral lobe, and not in other lobes.
Yatsutomo Nakai, lead author on the study, mixed PhIP into food given to a group of rats for up to eight weeks, then studied the animals' prostates, intestines and spleens to look for genetic mutations.
After four weeks, all lobes had significantly elevated mutations compared to rats that did not ingest PhIP. After eight weeks, researchers observed a significant increase in proliferation only in the ventral lobe, indicating that PhIP caused additional "promotional" events only in that lobe.
"We stumbled across a new potential interaction between ingestion of cooked meat in the diet and cancer in the rat," stated co-author Angelo De Marzo. "For humans, the biggest problem is that it's extremely difficult to tell how much PhIP you've ingested, since different amounts are formed depending on cooking conditions."