Cancer gene gap mapped.

Cancer gene gap mapped

As chromosome mapping techniques improve, more and more diseases are being linked to specific genetic defects. Last week, small-cell lung cancer--a particularly deadly form of lung cancer --became the latest disease to have its genetic origins identified. And although scientists still don't know what causes the genetic defect that leads to the disease, the researchers who discovered the link say cigarette smoking is a candidate.

The research, which points to a missing pair of genes on chromosome 3 as the cause of the cancer, was performed by scientists at the National Cancer Institute and the Uniformed Services University of the Health Sciences in Bethesda, Md., and the University of Texas Health Sciences Center in San Antonio. Their findings are reported in the Oct. 1 NATURE.

As in a handful of other genetically linked cancers, the genes that are missing in small-cell lung cancer appear to be cancer-suppressing "anti-oncogenes.' When present, anti-oncogenes prevent the rampant replication characteristic of cancer cells (SN: 1/5/85, p.10). The mapping of such genes is the first step toward identifying the biological product for which they code, and may in turn lead to improved diagnosis and treatment of the diseases they normally prevent. Small-cell lung cancer accounts for about 20 percent of the 30,000 to 40,000 new cases of lung cancer that appear in the United States each year. Overall, lung cancer is the country's leading cause of cancer death.