Based on early evidence of fossilized bone tumors that were found in ancient Egyptian mummies, cancer is an ancient disease.1 The term “carcinoma” to refer to cancer was first used around 400 BC by Hippocrates.2 The understanding of cancer mechanisms began when John Bennett and Rudolf Virchow observed the abnormal accumulation of white blood cells in patients in 1845, which was one of the first cancers detected by microscopy.3 In contrast to the long history of the disease, diagnosis and treatment of cancer at a cellular or molecular level is a relatively new strategy. Although the field of oncology has developed and expanded dramatically, a single drug has not yet been discovered that can cure all patients, even those with similar cancer types. We now know that cancer is an extremely heterogeneous disease, which explains differences not only between cancer cells from different patients, but also between cancer cells within a single patient.4 Clearly, more effective strategies are critically needed to defeat the long-standing enemy known as cancer.