Researchers discover gene linked to various cancers

A researcher at UT Southwestern has helped locate mutations in a gene linked to the progression of colon, brain and other cancers, a finding that eventually could lead to new therapies and diagnostic tests targeting the gene.

The gene in which the mutations were found, PIK3CA, is part of a family of genes encoding lipid kinases, enzymes that modify fatty molecules and direct cells to grow, change shape and move. Although scientists have been studying the biochemical properties of this family of genes for years, until now no study had revealed that they were mutated in cancer.

Kinases have been the focus of recent drug development strategies, with some kinase-inhibiting compounds such as Gleevec and Herceptin already being used clinically to inhibit tumor growth.

In a study reported in Science Express online, Dr. Adi Gazdar, professor of pathology in the Nancy B. and Jake L. Hamon Center for Therapeutic Oncology Research and contributing author, and his colleagues sequenced the molecular code of the genes in a lipid kinase family and found mistakes in the nucleotides, or DNA building blocks, in PIK3CA. The PIK3CA mutations were found in cancers of the colon, breast, lung, stomach and brain.

The researchers, primarily from the Johns Hopkins Kimmel Cancer Center, also showed the mutations increase PIK3CA activity, which can start a cascade of cellular events that spark a normal cell to grow un controllably and become cancerous. Most of the PIK3CA mutations are located in two DNA cancer "hot spots," thus making molecular diagnostic tests possibly easier to develop, said Dr. Gazdar, holder of the W. Ray Wallace Distinguished Chair in Molecular Oncology Research.


Scott Maier