This blog post examines the progression of anticancer drug development and whether it is transforming cancer from an incurable disease into a treatable one.
“It’s cancer.” The tragic heroine has leukemia. She thinks, “Why me?” But in modern society, cancer is not a disease that “just happens” to strike. Fear and worry about cancer have become a familiar reality for everyone. The fact that this disease doesn’t just affect specific individuals, but is a problem any of us could face, makes us even more anxious. According to statistics from South Korea’s Ministry of Health and Welfare, the probability of developing cancer by the average life expectancy (81 years) was 36.4%. For men (77 years), it was estimated that 2 out of 5 (37.6%) would develop cancer, while for women (84 years), it was 1 out of 3 (33.3%). Cancer has now become a common disease that can strike anyone without exception, no longer just the tragic heroine of a story.
Cancer can be likened to a wolf in sheep’s clothing. Infectious diseases like the common cold or eye infections can often be naturally cured because our immune cells, acting like the body’s police, recognize the bacteria or viruses causing the illness and destroy them. Thanks to the immune system performing its role, we can recover from infectious diseases without direct intervention in most cases. Cancer is different. However, because cancer cells arise from mutations accumulating in normal cells, they possess a similar appearance to normal cells, allowing them to evade the immune system’s patrol. Cancer cells, though stripped of their core functionalities, cleverly evade the immune system, dividing incessantly and disrupting the functioning of other healthy cells. Therefore, to combat cancer—like a runaway colt—we need special weapons to replace our immune system. The special weapon humanity discovered is the anticancer drug.
The origins of anticancer drugs trace back to the early 20th century, during the height of World War II. When enemy gas masks rendered conventional poison gas attacks ineffective, the German army began using sulfur mustard, also known as ‘mustard gas,’ as a biochemical weapon capable of attacking exposed skin. Mustard gas is an extremely potent poison gas. Exposure causes symptoms ranging from mild blisters on the skin and mucous membranes and nausea to severe cases of blindness. As the highly toxic mustard gas was used as a weapon of war, causing numerous casualties, the American side launched extensive medical investigations on patients exposed to mustard gas. During this process, various biochemical characteristics of mustard gas were identified. Unexpectedly, it was also discovered that mustard gas possessed anti-cancer effects. Thus, a poisonous gas developed to effectively massacre people became the precursor to anti-cancer drugs that inhibit the excessive proliferation of cancer cells and contribute to extending human life.
However, sulfur mustard is a method that kills not only wolves in sheep’s clothing but also genuine sheep. Cancer cells divide much faster than normal cells and spread throughout the body. Sulfamustard inhibits cell division, preventing cancer cells from growing. However, because it uniformly suppresses all cell division, it affects not only cancer cells but also the division process of normal cells. Therefore, administering sulfur mustard causes side effects that impair the function of skin, stomach lining, hair, and immune cells—all of which undergo active cell division under normal conditions. This is precisely why chemotherapy leads to hair loss and vomiting.
Patients suffering these side effects often complain that the pain of the treatment is as severe as the cancer itself. However, at the time, it was the best choice to save lives, so many patients had no choice but to undergo chemotherapy, enduring hair loss, vomiting, and even the risk of infection due to weakened immunity. Of course, enduring hair loss and vomiting was preferable to losing one’s life, so administering these anticancer drugs, despite their severe side effects, was unavoidable. However, as life-threatening infectious diseases were conquered by various antibiotics, antivirals, and vaccines, cancer emerged as one of the most severe diseases threatening human life, surpassing other illnesses. This heightened the need for effective cancer treatments with fewer side effects. To address this, a new concept of anticancer drugs emerged: drugs that distinguish between normal cells and cancer cells, targeting only the destruction of cancer cells. These drugs are also called targeted anticancer drugs because they recognize characteristics unique to cancer cells and selectively inhibit only the division of cancer cells, excluding normal cells. Many anticancer drugs used recently belong to this category.
A representative example of targeted anticancer drugs is angiogenesis inhibitors. As explained earlier, cancer cells divide at a very rapid rate and therefore require more nutrients than normal cells. To achieve this, cancer cells send signals to induce the formation of new blood vessels near themselves, allowing them to freely draw nutrients from the bloodstream. Anti-angiogenic agents are anticancer drugs that interfere with this very process. Rather than attacking cancer cells directly, they block the formation of blood vessels supplying nutrients to cancer cells, effectively starving the cancer cells by denying them food, thereby preventing further tumor growth. Starting with the discovery of endostatin, an angiogenesis inhibitor, by the O’Reilly research team in 1997, numerous angiogenesis inhibitors have been developed and are either in use or nearing commercialization. These include Avastin (bevacizumab), widely used for colorectal cancer, and the domestically developed DWM-M01A and DWM-M01S.
For modern people, ‘cancer’ is likely the most feared disease. This is because there is a perception that cancer is an unavoidably fatal illness. However, the situation is not as dire as it seems. Research on cancer and the development of treatments are progressing faster than ever before, and especially in recent years, innovative therapies have been developed one after another. Cancer is no longer viewed solely as a fatal disease as it was in the past; it is transforming into a chronic disease that can be treated and managed. The history of anticancer drugs spans less than a century. Within this brief period, the field of cancer treatment has achieved remarkable progress. Recently, many effective treatment methods have been developed, and even if cancer develops, the probability of surviving within five years after starting treatment increases every year. As research continues worldwide to elucidate the mechanisms of cancer development and develop effective anticancer drugs, it is reasonable to dream of a world free from cancer concerns.
