Using technology that makes it possible to zoom in on smaller sections of cell chromosomes than ever before, researchers at Dana-Farber Cancer Institute have identified nearly 100 chromosome regions where genes are either over-copied or missing in non-small cell lung cancer.
The findings provide new clues about the location of genes potentially involved in the most common type of lung cancer - and one of the deadliest of all malignancies - and a range of possible targets for future therapies.
The study will be reported in the Proceedings of the National Academy of Sciences' Online Early Edition the week of June 27.
"Previous studies have identified a small set of mutated, or abnormal, genes that are associated with non-small cell lung cancer," says the study's lead author, Giovanni Tonon, MD, PhD, of Dana-Farber. "But we also know that the chromosomes of these cells contain a large number of irregular regions - where genes have either been deleted or copied over and over again - which suggests that a large number of cancer genes remain to be discovered. The purpose of this study was to locate the likeliest candidates."
The study is part of a renewed effort by scientists worldwide to uncover the basic biology of lung cancer, the number one cause of cancer-related deaths in the United States. Non-small cell lung cancer (NSCLC) accounts for about 75 percent of all lung cancers and is responsible for nearly 120,000 deaths in this country annually. It is one of the most difficult cancers to treat, with only 15 percent of patients surviving more than five years after diagnosis.
In recent years, technological advances have brought new precision to the search for gene abnormalities associated with cancer. In the current study, Dana-Farber researchers used two forms of microarray technology to bring such abnormalities into focus.
Using tumor samples from 44 NSCLC patients and 34 laboratory-grown lines of NSCLC cells, investigators scanned the cells with high-resolution cDNA (oligonucleotide) microarray equipment to find chromosome regions containing unusual numbers of gene copies. The technology, developed in conjunction with Agilent Technologies, was 50-100 times more powerful than had been used on NSCLC cells in the past, enabling researchers to identify irregular sites more precisely. They found a total of 93 regions, each containing about 11 genes, where gene deletions or over-copying had occurred.