The Story of Hydra: Portrait of Cancer as a Stem-Cell Disease

The questions we ask in this book about cancer are actually quite elementary. What is the origin of cancer? Does cancer arise in any cell in the body, or only in certain cells? Is cancer a genetic or a stem-cell disease? We illustrate that cancer is a multicellular rather than a unicellular process, a cellular rather than a genetic problem, and a stem-cell rather than a somatic-cell disease. We reveal that the incredible resemblance between a cancer cell and a stem cell suggests that they are intimately related. The uncanny ingenuity of a cancer cell is also innate in a stem cell. The recognition that cancer has a stem-cell origin indicates that a stem-cell theory of cancer may be the unified theory that we need to make sense of the torrents of new data and new insights into different facets of cancer, to see how they fit together into one picture, and to disarm the disease. A stem-cell theory of cancer can potentially accept, embrace, and integrate all of its genetic, epigenetic, proteomic, and metabolic aspects. Such a unified theory can account for all cancer hallmarks, including metastasis, heterogeneity, dormancy, and immune evasion. It predicts that multimodal therapy may be more beneficial than targeted therapy, and integrated medicine more effective than precision medicine for the management of all but the simplest tumors. It predicts that when we have the correct cancer theory, clinical progress will advance by monumental leaps rather than incremental steps. Indeed, I predict that successful clinical outcomes will ultimately provide irrefutable validation that cancer is a stem-cell disease. Therefore, the thesis of this book is actually quite simple. When we have a pertinent and correct theory of the origin of cancer, all ideas, observations, experiments, and treatments will begin to fall into place and make perfect sense. We would like to convince readers that a stem-cell theory is the elusive, long-sought unified theory, the theory of all theories, of cancer.