It is so fundamental to most cancers that a positron emission tomography (PET) scan, which has emerged as an important tool in the staging and diagnosis of cancer, works simply by revealing the places in the body where cells are consuming extra glucose. Warburg’s discovery, later named the Warburg effect, is estimated to occur in up to 80 percent of cancers.
The cancer cells were ravenous for glucose.
But when Warburg tested additional tumors, including ones from humans, he saw the same effect every time. Oxygen-fueled reactions are a much more efficient way of turning food into energy, and there was plenty of oxygen available for the cancer cells to use. Instead, the cancer cells fueled their growth by swallowing up enormous amounts of glucose (blood sugar) and breaking it down without oxygen. By the time Warburg turned his attention from sea-urchin cells to the cells of a rat tumor, in 1923, he knew that sea-urchin eggs increased their oxygen consumption significantly as they grew, so he expected to see a similar need for extra oxygen in the rat tumor. Rather, Warburg was focused on energy, specifically on how the eggs fueled their growth. Unlike Boveri, Warburg wasn’t interested in the chromosomes of sea-urchin eggs. But in the following decades, Warburg’s discovery would largely disappear from the cancer narrative, his contributions considered so negligible that they were left out of textbooks altogether. His research, too, was hailed as a major breakthrough in our understanding of cancer. Today Boveri is celebrated for discovering the origins of cancer, but another German scientist, Otto Warburg, was studying sea-urchin eggs around the same time as Boveri. It was the era before modern genetics, but Boveri was aware that cancer cells, like the deformed sea urchin cells, had abnormal chromosomes whatever caused cancer, he surmised, had something to do with chromosomes. In the first decade of the 20th century, the German biologist Theodor Boveri discovered that if he fertilized sea-urchin eggs with two sperm rather than one, some of the cells would end up with the wrong number of chromosomes and fail to develop properly. The story of modern cancer research begins, somewhat improbably, with the sea urchin.