A large-scale survey of genetic changes in lung tumors has identified 26 frequently altered genes in the most common form of the disease, lung adenocarcinoma. The discovery, reported in the October 23 Nature, increases the number of genes associated with lung cancer and expands the base of knowledge about the genetics of this deadly disease.

The Tumor Sequencing Project, a group of academic researchers funded by the National Human Genome Research Institute, analyzed more than 600 genes in 188 lung tumors for noninherited mutations as well as gains and losses of DNA. Their integrated analysis supports the view of cancer as a disease in which core biological pathways may be altered by various types of changes in multiple genes.

For instance, more than two-thirds of the tumors had at least one mutation affecting the MAPK pathway. Lung cancer patients with these changes may benefit from drugs that affect this pathway, the researchers suggest, noting that compounds called MEK inhibitors have produced promising results in mouse models of colon cancer.

The findings complement other large-scale genomic studies, including an analysis of glioblastoma brain tumors by The Cancer Genome Atlas (TCGA) project that appears in the same issue (the findings were published online in September).

In both the lung and brain studies, new mutations were identified in some of the same cancer-causing genes, noted Dr. Matthew Myerson of the Dana-Farber Cancer Institute, who was a leader of both studies. The overlap suggests that despite the diversity of genetic changes in cancer, some targeted therapies will be effective in multiple tumor types, he said in a conference call with reporters. Current examples of such drugs include imatinib (Gleevec) and cetuximab (Erbitux).