Highly Mutated Oncogene Linked to Five Types of Cancer

Cancer researchers have found that mutations in the PIK3CA lipid kinase gene are characteristic of certain types of cancers and pre-cancerous tissues, a finding that may lead to the development of new diagnostic tests and therapeutic approaches centered on this gene.

Phosphatidylinositol 3-kinases (PI3Ks) are important regulators of signaling pathways that control cell survival, proliferation, adhesion, and movement. Investigators at Johns Hopkins University (Baltimore, MD, USA; www.jhu.edu) sequenced PIK3CA from many types of tumors and other tissues. They found that mutations due to the switching of a single nucleotide were present in 32% of colon cancer samples, 27% of glioblastomas, 25% of gastric cancers, 8% of breast cancers, and 4% of lung cancers. In addition, PIK3CA mutations were found in samples taken from pre-malignant colon tumors. These findings, which suggest that PIK3CA may be one of the most highly mutated oncogenes yet identified in human cancers, were published in the March 11, 2004, online edition of Science.

"These findings open the door to developing specific therapies that may prove useful for the treatment of cancers with mutations in PIK3CA,” explained senior author Dr. Victor Velculescu, assistant professor of oncology at Johns Hopkins University. "This kind of information, gleaned from sequencing a patient's tumor, means drugs could be targeted to just the right molecular pathway at just the right time and potentially be more effective with fewer side effects.”




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