In Honor of Alfred G. Knudson, a Pioneer in Retinoblastoma Research

Alfred G. Knudson will always be remembered for his groundbreaking research in cancer, specifically pediatric retinoblastoma. His work helped to decode this mysterious disease, examining why and how certain forms of cancer attack in relation to the patient’s genetics. On July 10, 2016, he passed away in his Philadelphia home at the age of 93.

Cancer Genetics Advancements

During the 1970s, scientists observed that some forms of cancer are hereditary. However, they weren’t able to explain how some with a family history could remain cancer-free, while others with no family history could be struck by the disease. Dr. Knudson’s work presented the medical community with a breakthrough in understanding the underlying mechanics of cancer genetics. His research has paved the way for a number of subsequent cancer advancements.

Focus on Pediatric Retinoblastoma

To study the conundrum of cancer genetics, Dr. Knudson opted to examine cases of pediatric retinoblastoma. He chose this form of cancer due to the fact it develops early in life, which means that patients are less likely to have experienced possible genetic mutations that adults may experience over their lifetime. He viewed retinoblastoma as a relatively pure form of cancer, and studied and statistically analyzed the two types of retinoblastoma: hereditary and non-hereditary.

Cancer’s “Two-Hit” Hypothesis

In 1971, Dr. Knudson published his world-famous findings on the “two-hit” theory of cancer genetics, also referred to as the Knudson hypothesis or the multiple-hit hypothesis. He theorized that hereditary retinoblastoma patients inherited one or more damaged genes from a parent, which is not enough to result in cancer. However, cancer may develop after a “second hit” to the patient, which may be a DNA defect, radiation exposure, and the like. In non-hereditary retinoblastoma, the patient has healthy parental genes, and therefore must experience two genetic hits.

Later, he used this research to theorize the existence of antioncogenes, or genes that stop cells from becoming cancerous. A decade later, this was confirmed, and they are now known as tumor suppressor genes. As years passed, Dr. Knudson’s work in pediatric retinoblastoma laid groundwork for all types of hereditary cancer. He’s opened the doors for early detection and prevention in individuals with known cancer predispositions.

Knudson’s Accolades

As one of the most renowned researchers of the field, Dr. Knudson has garnered esteem from the world over. In 1998, he received the Lasker Award, which is referred to as the American Nobel Prize. In 2004, he won the Kyoto Prize that recognized him for opening the horizon for cancer genetics and playing a key role in its developments.

Dr. Knudson’s dedication and service continues to garner respect and esteem from the medical community. To learn more about his life and work, visit the American Association for Cancer Research.