Historically Speaking: The Quest to Understand Skin Cancer

The 20th-century surgeon Frederic Mohs made a key breakthrough in treating a disease first described in ancient Greece.

The Wall Street Journal

June 30, 2022

July 1 marks the 20th anniversary of the death of Dr. Frederic Mohs, the Wisconsin surgeon who revolutionized the treatment of skin cancer, the most common form of cancer in the U.S. Before Mohs achieved his breakthrough in 1936, the best available treatment was drastic surgery without even the certainty of a cure.

Skin cancer is by no means a new illness or confined to one part of the world; paleopathologists have found evidence of it in the skeletons of 2,400- year-old Peruvian mummies. But it wasn’t recognized as a distinct cancer by ancient physicians. Hippocrates in the 5th century B.C. came the closest, noting the existence of deadly “black tumors (melas oma) with metastasis.” He was almost certainly describing malignant melanoma, a skin cancer that spreads quickly, as opposed to the other two main types, basal cell and squamous cell carcinoma.


After Hippocrates, nearly 2,000 years elapsed before earnest discussions about black metastasizing tumors began to appear in medical writings. The first surgical removal of a melanoma took place in London in 1787. The surgeon involved, a Scotsman named John Hunter, was mystified by the large squishy thing he had removed from his patient’s jaw, calling it a “cancerous fungus excrescence.”

The “fungoid disease,” as some referred to skin cancer, yielded up its secrets by slow degrees. In 1806 René Laënnec, the inventor of the stethoscope, published a paper in France on the metastatic properties of “La Melanose.” Two decades later, Arthur Jacob in Ireland identified basal cell carcinoma, which was initially referred to as “rodent ulcer” because the ragged edges of the tumors looked as though they had been gnawed by a mouse.

By the beginning of the 20th century, doctors had become increasingly adept at identifying skin cancers in animals as well as humans, making the lack of treatment options all the more frustrating. In 1933, Mohs was a 23-year-old medical student assisting on cancer research in rats when he noticed the destructive effect of zinc chloride on malignant tissue. Excited by its potential, within three years he had developed a zinc chloride paste and a technique for using it on cancerous lesions.

He initially described it as “chemosurgery” since the cancer was removed layer by layer. The results for his patients, all of whom were either inmates of the local prison or the mental health hospital, were astounding. Even so, his method was so novel that the Dane County Medical Association in Wisconsin accused him of quackery and tried to revoke his medical license.

Mohs continued to encounter stiff resistance until the early 1940s, when the Quislings, a prominent Wisconsin family, turned to him out of sheer desperation. Their son, Abe, had a lemon-sized tumor on his neck which other doctors had declared to be inoperable and fatal. His recovery silenced Mohs’s critics, although the doubters remained an obstacle for several more decades. Nowadays, a modern version of ”Mohs surgery,” using a scalpel instead of a paste, is the gold standard for treating many forms of skin cancer.

WSJ Historically Speaking: Serendipity of Science is Often Born of Years of Labor

Over the centuries, lucky discoveries depend on training and discernment


One recent example comes from an international scientific team studying the bacterium, Ideonella sakaiensis 201-F6, which makes an enzyme that breaks down the most commonly used form of plastic, thus allowing the bacterium to eat it. As reported last month in the Proceedings of the National Academy of Sciences, in the course of their research the scientists accidentally created an enzyme even better at dissolving the plastic. It’s still early days, but we may have moved a step closer to solving the man-made scourge of plastics pollution.

The development illustrates a truth about seemingly serendipitous discoveries: The “serendipity” part is usually the result of years of experimentation—and failure. A new book by two business professors at Wharton and a biology professor, “Managing Discovery in the Life Sciences,” argues that governments and pharmaceutical companies should adopt more flexible funding requirements—otherwise innovation and creativity could end up stifled by the drive for quick, concrete results. As one of the authors, Philip Rea, argues, serendipity means “getting answers to questions that were never posed.”

So much depends on who has observed the accident, too. As Joseph Henry, the first head of the Smithsonian Institution, said, “The seeds of great discoveries are constantly floating around us, but they only take root in minds well prepared to receive them.”

One famously lucky meeting of perception and conception happened in 1666, when Isaac Newton observed an apple fall from the tree. (The details remain hazy, but there’s no evidence that the fruit actually hit him, as legend has it.) Newton had seen apples fall before, of course, but this time the sight inspired him to ask questions about gravity’s relationship to the rules of motion that he was contemplating. Still, it took Newton another 20 years of work before he published his Law of Universal Gravitation.

Bad weather was the catalyst for another revelation, leading to physicist Henri Becquerel’s discovery of radioactivity in 1896. Unable to continue his photographic X-ray experiments on the effect of sunlight on uranium salt, Becquerel put the plates in a drawer. They developed, incredibly, without light. Realizing that he had been pursing the wrong question, Becquerel started again, this time focusing on uranium itself as a radiation emitter.

As for inventions, accident and inadvertence played a role in the development of Post-it Notes and microwave heating. During the 1990s, Viagra failed miserably in trials as a treatment for angina, but alert researchers at Pfizer realized that one of the side effects could have global appeal.

The most famous accidental medical discovery is antibiotics. The biologist Alexander Fleming discovered penicillin in 1928 after he went on vacation, leaving a petri dish of bacteria out in the laboratory. On his return, the dish had developed mold, with a clean area around it. Fleming realized that something in the mold must have killed off the bacteria.

That ability to ask the right questions can be more important than knowing the right answers. Funders of science should take note.