A medical breakthrough is an event that transforms a disease, treatment or condition. These are some of the big ones:

In 1846, dentist William TG Morton uses ether to anesthetize patients for surgery for the first time. This allows surgeons to operate without the excruciating pain that had previously limited their abilities.

Researchers at Mass General and MIT develop a laser treatment that removes pigmented lesions and tattoos without scarring. The technology later enables doctors to treat port-wine stains and other inherited skin conditions. HMS professor and Alexander Rich Distinguished Investigator Jack Szostak discovers telomeres, the regions of DNA that protect chromosomes but get shorter each time the cell divides. This and his work on the enzyme telomerase led to Szostak’s sharing the 2009 Nobel Prize in Physiology or Medicine.

Renowned heart surgeon Dr. Joseph Murray performs the first kidney transplant in 1954, opening a new window for those waiting for organs. He also develops a bypass graft procedure to restore blood flow through blocked coronary arteries, significantly decreasing the risk of heart attack and stroke.

Scientists with the International Human Genome Project announce a rough draft of the entire set of genes in the human body and begin to unravel what they do. They also develop a technique for manipulating DNA, paving the way for gene therapy and other genetic engineering applications.

Previously, people with type 1 diabetes lived only 1.5 years after their diagnosis. Joslin physician Priscilla White introduces the White classification system, which helps women who are diabetic to manage their pregnancy. She also develops insulin, which dramatically increased lifespans and reduced the debilitating symptoms of the disease.