A new drug could prove useful in treating small cell lung cancer — the most aggressive form of lung cancer, researchers report. Scientists tested a drug — known as AZD3965 — on small cell lung cancer cells, with a focus on exploiting the change in energy production in tumors. In cancer cells, there is a switch to using glycolysis, a process that requires less oxygen and produces lactate as a by-product. Certain molecules — monocarboxylate transporters (MCTs) — are involved in the movement of lactate out of cells and drugs that target MCTs have been shown to stop tumor growth.