Skip to 0 minutes and 14 seconds SPEAKER: Although we’ve known about cancer for over 2,000 years, it has taken us a long time to understand what is actually going on in the disease. A number of people have contributed different ideas before we came to today’s perspective. In this video, I’m going to tell you the story of how our understanding of cancer has changed over time. Hippocrates, the famous Greek philosopher, was arguably the first person to come up with a theory of cancer. He coined the term, carcinoma, from the Greek karkinos, meaning crab, based on how cancer spread into normal tissue. Hippocrates had a theory that the body consisted of four humours– blood, phlegm, yellow bile, and black bile. When they were in balance, you were healthy.
Skip to 0 minutes and 56 seconds When they were out of balance, you got disease. In his theory, cancer was an excess of black bile, or, melaina chole, from which the term melancholia arises. The idea being that black bile also caused depression. Later, this theory was developed further by the physician Galen. He suggested that cancer was caused by black bile circulating throughout the body. And then it can then deposit in different areas and grow indefinitely. His views controlled medical thinking in the Western world for around 1,300 years. Things started to change when a Belgian guy called Andreas Vesalius came along, who was professor of anatomy in Padua in Italy. Vesalius took the radical step of actually testing these ideas by dissecting human bodies.
Skip to 1 minute and 43 seconds He failed to find any trace of black bile, thereby, basically shooting down Galen’s theory. So if black bile wasn’t the cause of cancer, what was? Well, let’s fast forward to Rudolf Virchow working in the 19th century. So this is after the microscope and after the discovery that the human body is made up of cells. And he had made the important discovery that all cells arise from other cells. Virchow started to examine patients with blood cell cancers. And rather than the presence of bile or pus, he noted that the blood of these patients had a milky white layer on top, due to an excessive number of white blood cells– cells that were present in normal blood, but in much smaller numbers.
Skip to 2 minutes and 26 seconds In fact, he named the disease after this observation. Initially, he called it weisses blut, meaning white blood in German. Then, he changed it to the Greek, using leukos, meaning white, and aemia, meaning blood. The disease– leukaemia. Virchow’s observations and those of others around the same time were some of the first indications of a fundamental principle of cancer, and one that still holds true today– cancer is caused by our own body’s cells multiplying out of control. Nowadays, we have a much more sophisticated understanding of what cancer is. And scientists recognise there are certain recurring hallmark features of the disease. These include the fact that cancer cells contain changes to their genetic code, their DNA, compared to normal cells.
Skip to 3 minutes and 14 seconds In other words, mutations– making them subtly, but importantly, different. The fact that cancer cells are often self-sufficient in terms of growth signals, explaining how they grow outside of the normal controls. The fact that unlike normal cells, cancer cells can multiply indefinitely without stopping. They are essentially immortal. Finally, we understand a lot more about how the changes that take place in cancer cells enable them to spread around the body. However, despite this, they still, at a fundamental level, are our own cells– the point that is really important when it comes to how our immune system sees cancer.
What is cancer?
In this video, Professor Ben Willcox describes what cancer is and how perceptions of it changed dramatically over time before we came to today’s perspective.
Reflect on any new information or ideas and share your thoughts with other learners in the comments area.
If you would like to learn more about the history of cancer, you might like to read ‘The Emperor of All Maladies: A Biography of Cancer’ by Siddhartha Mukherjee, which is available to purchase on Amazon.
© Cancer Immunology and Immunotherapy Centre, University of Birmingham