Ancient viral DNA helps embryonic stem cells grow—and cancer hijacks the same switch

Three years ago, George Kassiotis and his team made an unexpected discovery: A specific way of producing a protein called calbindin was found to help cancer cells survive by preventing them from aging. This left Kassiotis, who runs the Crick's Retroviral Immunology Laboratory, confused. Why would a mechanism that boosts cancer growth exist in the first place?