Why do we need to eat food to live? Food is made up of many different classes of molecules. Some food we eat are protein rich whiles others have lots of sugar. Some food have combinations of both. One of the main constituents of food that we need to live is glucose. Although it may not seem apparent in the ingredients list, it is usually a component of a polymer, such as starch.
Glucose is fuel for our cells. Our cells use glucose for a process called glycolysis, which makes by products for a process called the Krebs cycle, which makes byproducts for a process called the electron transport chain (ETC, or ox-phos.) Ox-phos, in the presences of oxygen, gives the cells majority of its energy, while glycolysis provides some but less.
Like all cells, cancer cells also need fuel to live. What was discovered is that cancer cells shift how they manipulate energetics differently from other cells.
The Warburg Effect. Some cancer cells, even if they have adequate oxygen supply, remain in glycolysis instead of going to ox-phos. This seems non-intuitive, as glycolysis provides much less energy for the cell. But there may be other reasons for this. A byproduct of glycolysis is useful in creating the building block of DNA, which is a useful molecule to have when rapidly dividing.
Environmental effects. Another byproduct of glycolysis is lactate. This molecule can diffuse out of the cell and go to surrounding tissue. Lactate can be converted back into glucose by these cells via another metabolic process. Thus, these cells are being fueled by the cells undergoing the Warburg effect.
Sources: Sci Adv. 2016 May; 2(5): e1600200.
Hanahan, Douglas, and Robert A Weinberg. “Hallmarks of Cancer: the next Generation.” Cell, U.S. National Library of Medicine, 4 Mar. 2011, http://www.ncbi.nlm.nih.gov/pubmed/21376230.
https://byjus.com/biology/metabolism/
Topics in Cancer Biology 