Major Cancer Drugs Have Come from Unexpected Sources
(p. 182) Starting in the last decades of the twentieth century, last decades of the twentieth century, sophisticated genetics and molecular biology have been aimed toward a more precise understanding of the cell's mechanisms. Yet, even here, chance has continued to be a big factor. Surprising discoveries led to uncovering cancer-inducing genes (oncogenes) and tumor-suppressing genes, both of which are normal cellular genes that, when mutated, can induce a biological effect that predisposes the cell to cancer development. A search for blood substitutes led to anti-angiogenesis drugs. Veterinary medicine led to oncogenes and vaccine preparations to tumor-suppressor genes. In one of the greatest serendipitous discoveries of (p. 183) modern medicine, stem cells were stumbled upon during research on radiation effects on the blood.
Experience has clearly shown that major cancer drugs have been discovered by independent, thoughtful, and self-motivated researchers--the cancer war's "guerrillas," to use the reigning metaphor--from unexpected sources: from chemical warfare (nitrogen mustard), nutritional research (methotrexate), medicinal folklore (the vinca alkaloids), bacteriologic research (cisplatin), biochemistry research (sex hormones), blood storage research (angiogenic inhibitors), clinical observations (COX-2 inhibitors), and embryology (thalidomide).
Meyers, Morton A. Happy Accidents: Serendipity in Modern Medical Breakthroughs. New York: Arcade Publishing, 2007.