Researchers have cataloged the mutations in genes that produce protein kinases, which are enzymes that regulate other proteins and play a role in some cancers. Using DNA from 210 diverse human cancers, the researchers sequenced 518 protein kinase genes. Approximately 120 of the genes carried a mutation related to cancer development and may function as cancer genes, the researchers reported in the March 8 Nature.

Drs. Andrew Futreal and Michael Stratton of the Wellcome Trust Sanger Institute in Cambridge, U.K., and their colleagues identified more than 1,000 mutations in the gene family, but only some of these are so-called “driver” mutations that drive the cancer. The others are “passenger” mutations, which are present in tumors but may not contribute to disease. Their results suggest that most mutations in cancer cells are likely to be passenger mutations.

Mutations were relatively common in cancers of the lung, stomach, ovary, colon, and kidney, and rare in cancers of the testis and breast. “Given that we have studied only 518 genes and limited numbers of each cancer type, it seems likely that the repertoire of mutated human cancer genes is larger than previously envisaged,” the researchers wrote.

Together with another large-scale sequencing study published in September 2006, this study presents a largely unbiased overview of the spectrum of mutations in human cancers, noted an editorial by Drs. Daniel Haber and Jeff Settleman of Massachusetts General Hospital. These studies suggest that “each cancer genome carries many unique abnormalities, and not all mutations identified contribute equally to the manifestation of the associated cancers,” they wrote.