The Predator's False Promise: Pseudoscience over Reason

Over 11 million people are diagnosed with cancer world wide each year, 7 million of which will not survive. With early detection, one-third of all cancers can generally be cured by surgery, chemotherapy or radiotherapy (1). Nonetheless, cancer treatment and detection is amongst the biggest medical challenges faced by our societies today.  Ever since the late 1980s there have been reports, articles and stories about “cancer defying sharks” and how these fearful predators potentially hold the secret weapon in our fight against cancer. These stories were commercially publicized by an entrepreneur named I. William Lane, who claimed that shark cartilage could treat and cure cancer, arthritis, enteritis (an inflammation of the intestinal tract), macular degeneration, psoriasis, acne and poison ivy (2). These claims became widely publicized and many companies in the US began marketing these shark cartilage “supplements”. Oncologists also noticed that an increasing amount of their patients were asking about shark cartilage treatments or had already tried this form of alternative therapy (3). Many were so eager to believe the idea of finding such an idealistic cure for cancer, that they did not bother to search for the scientific evidence supporting the alleged “magical properties” of powdered shark cartilage.

The basic idea behind the theory of cancer curing sharks originated from the belief that sharks could not get cancer. Sharks have survived on earth for over 400 million years and one of the possible explanations for this probably lies in their immunity to cancer and other diseases. If this theory is correct, humans may some day benefit, however; there is little to no empirical evidence that suggests that we have found a practical way of using this immunity to aid our own immune systems. Contrary to public belief (mainly due to the media), sharks in fact, do get cancer, even though there are only a small number of documented cases (4). Gary Ostrander, a professor of biology and comparative medicine at John’s Hopkins University decided to investigate these “shark cartilage cure” claims. He discovered that there were over forty cases of benign and malignant tumors in sharks and in their close relatives. He also researched scientific journals to see if there had been any prior research done that demonstrated that shark cartilage was useful in cancer treatments and such study was found (3).

Advocates for shark cartilage, including William Lane, say that the key lies in an angiogenesis inhibitor. Angiogenesis, or the development of blood vessels, play an important role in the growth of a tumor (2). In order to support a tumor’s high metabolism, they produce a hormone called angiogenin which causes new branches of blood vessels to be grown around the tumor. These blood vessels bring in nutrients that feed the tumor, allowing it to grow. The vessels also carry away waste products that can cause metastasis, which occurs when a part of the tumor breaks away and starts another cancerous tumor in another part of the body. Shark cartilage contains an “angiogenin inhibiting” property that prevents the formation of new blood vessels. The basic idea is to deny the tumor its feeding mechanism and let the tumor eventually destroy itself with its own waste products (5). There are however, several problems with this theory. Firstly, there have been documented cases of sharks getting tumors on the very cartilage advocates for this treatment say are cancer proof. In addition, the cartilage tissue of other animals, including humans, have anti-angiogenic factors in them as well (6). What’s to say that simply ingesting powered shark cartilage will help fight tumors anywhere in the body? 

William Lane claims that the active component in shark cartilage that fights tumors is located in the protein. He says that six or seven proteins have vessel growth preventing abilities and the higher the percentage of these proteins in the cartilage supplements, the more effective the treatment. Lane tested his shark cartilage treatments in Mexico and Cuba in which the only therapy used for his patients was the shark cartilage pills. He reported that after eleven weeks of treatment, five of his patients were completely tumor free, that he managed to reduce 85% of the other patients’ tumor and caused only one fatality. He reported to have treated patients with terminal prostate, breast, brain, stomach, liver, ovarian and uterus cancer and had incredible success with those that survived (2). After the revelation of these cases, Lane attracted international attention. In 1993 he appeared in the television show 60 Minutes alongside Cuban physicians and patients who had participated in his investigation. Lane published books and came up with his own brand of shark cartilage bills, Benefin. Other companies saw the marketing opportunity and also entered the industry. A bottle containing 750 milligrams sells for around $28, recommending taking eight pills a day, which would amount to $77 per month. Due to the refusal of Andrew Lane (William Lane’s son), president of Lane Labs to disclose the company’s profits, it is difficult to estimate the worth of the entire industry. Calculations indicate that in 1995, the international market for shark cartilage products amounted to over $30 million (3).

Henry Brem, professor of neurosurgery, oncology and ophthalmology at Johns Hopkins School of Medicine, and also one of the researchers who contributed to the building of the field of cartilage research, calls Lane’s conclusions as “a distortion of science”. The only clinical studies done on humans were in Cuba and Mexico and they lacked controls. Brem says “None would meet the standards of what we do in clinical trials here. We never showed that the oral form [of cartilage] has any benefit. Because A equals B doesn’t mean that C equals D. Because shark cartilage has antiangiogenic activity doesn’t mean that crushing it up and swallowing it does.” Brem explains that the proteins that Lane claims to have such incredible properties will probably be broken down by enzymes in our stomachs and not stay intact long enough to make it into the bloodstream and fight a tumor (3).

The real tragedy lies in the fact that some patients are choosing this form of treatment over chemotherapy or radiation and dying. A Canadian physician described a case in which the parents of a nine year old girl opted for shark cartilage treatment instead of post-surgery recommended radiation and chemotherapy, which would have given her a 50% survival rate. The girl died. The problem is that patients are believing products such as Benefin to be a drug, rather than just a dietary supplement (3). The increased misinformed belief in the value of shark cartilages also cause environmental damage. There is no telling how much the ecosystem will suffer from the decrease in population of one of its top predators (6). Desperate cancer patients are being exploited, critical patient resources are being consumed by something that does not contain proven therapeutic value and sharks are needlessly being destroyed. That, unfortunately, is the sad truth about the shark cartilage myth.

1.      World Health Organization: Cancer

2.      William Lane: “Sharks Don’t Get Cancer”

3.     John’s Hopkins Magazine: “Predators Promise”

4.      National Geographic News: "Do Sharks hold secret to human cancer fight?"

5.      Biology of Sharks and Rays

6.      BBC News: “Shark cancer claims rubbished"