Tumor Suppressor Gene Located In Liver Ca...( ars at Duke University investigating th...)

The gene is also interesting to researchers because it could help to explain why mice appear to be more prone to liver tumor formation than humans. Mice normally have only one active copy of this tumor suppressor gene rather than the two working copies humans possess. This evolutionary oddity could have important implications for species susceptibility to liver tumors and human risk assessment.

Animals and humans have two functional copies of almost every gene, one from each parent. In rare cases, a gene is imprinted, meaning that only one of the parental copies is active. The M6P/IGF2r is especially unusual, because it is imprinted in mice but not in humans. Lacking the back-up that humans have in case one copy malfunctions, mice are more likely to lose complete function of this gene, the researchers said.

If further studies show that loss of the M6P/IGF2r function is important in the way chemicals cause liver tumors in rats, the scientists explained, then pharmaceutical companies could take into account the decreased likelihood of this genetic loss occurring in humans when determining whether to pursue the testing of a promising new drug.

Jirtle and his colleagues are continuing their studies of the M6P/IGF2r by investigating whether this gene also plays a role in the formation of other types of tumors. After four years of study, Jirtle said, "We are at the end of the beginning."

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Contact: David Rice
rice0014@mc.duke.edu
Duke University
29-Apr-1996