Researchers from the National Institutes of Health have identified and tested a drug combination that exploits a weakness in small cell lung cancer (SCLC), an aggressive, dangerous cancer. The scientists targeted a vulnerability in how the cancer cells reproduce, increasing already high levels of replication stress—a hallmark of out-of-control cell growth in many cancers that can damage DNA and force cancer cells to constantly work to repair themselves. In a small clinical trial, the drug duo shrank the tumors of SCLC patients. The team reported its findings April 12 in Cancer Cell.