Researchers at UT Southwestern Medical Center said they have discovered what they called a vulnerability in the armor of a so-called “undruggable” lung cancer, and they have found an existing drug they said may provide a treatment.

In a release, UT Southwestern said the researchers were working in four separate labs when they found that the drug Selinexor (KPT-330) killed lung cancer cells and shrank tumors in mice when used against cancers driven by the KRAS cancer gene, one that is aggressive and difficult to treat.

Results of study were published recently in Nature.

Selinexor already is in clinical trials for treatment of other types of cancer, mostly for leukemia and lymphoma, but it’s also used in gynecological, prostate, brain, and head and neck cancers, according to the news release.

UT Southwestern said that lung cancer is the No. 1 cancer killer in the nation, and is responsible for more than 158,000 deaths per year. The KRAS oncogene is believed to be responsible for roughly 25 percent of all lung cancer cases in the nation, UT Southwestern said.

Dr. Pier Scaglioni, associate professor of internal medicine at UT Southwestern and a contributing author on the study, said that KRAS has been a target of study since its discovery in 1982, but because of its almost impervious spherical shape, nobody had been able to find an opening on the gene to attack.

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