Steve Jobs and the Limits of Sequencing

By Erika Check Hayden | October 25, 2011 | 12 Comments

The death of Steve Jobs is unfolding as a morality play between mainstream and alternative medicine, with doctors and bloggers blaming Jobs’ untimely demise on his decision to delay surgery while he tried acupuncture and herbal remedies.

The reality is that Jobs’ story tells us as much about the limits of conventional science and medicine as it does about alternative therapies.

In a new book, Walter Isaacson reveals that Jobs had his cancer genome sequenced as part of an aggressive program of treatments that he eventually embraced. The news that Jobs had his cancer sequenced is surprising in perhaps only one way: it’s one of the few high-profile examples we have that underscores the sobering fact that genome sequencing does not always lead to a cure.

At the time Jobs opted for sequencing, Isaacson writes, Jobs was one of only about 20 people in the world who had their cancers sequenced, and it cost him $100,000.

Now, many other tech icons, such as Gordon Moore and Sergey Brin, are among the host of celebrities, scientists and well-connected business titans who have lined up for genome sequencing, which is becoming inexpensive enough that more and more ordinary people are having their DNA analyzed too. One scientist has estimated that approximately 5,000 people will be sequenced this year, and 30,000 next year. Among these are hundreds of cancer patients around the world, though most are anonymous subjects in research studies.

Most publications about people who have been sequenced document how the sequence helped lead to a cure or better treatment. Sequencing revealed that a severely ill Wisconsin boy could be cured of his sickness by a bone marrow transplant, for instance, and that scientist Stephen Quake should take statins to combat an increased risk of heart disease. (He refused to do so).

Sadly, that is not how things played out for Jobs.

To sequence a cancer, genome, scientists take a sample of tissue from a patient’s tumor, then sequence DNA from the sampled tumor cells. By comparing the DNA sequence of Jobs’ cancer cells to that of his normal cells, scientists could pinpoint the mutations unique to his cancer.

Doctors apparently used this readout of the malign properties of Jobs’ tumor to guide him to more effective treatments. We don’t know – and may never know – what mutations his tumor contained, what drugs were used, whether they prolonged his life or allowed him to live a few extra months free of disease. But the general idea is that if one’s tumor contains genetic mutations that can be targeted by specific drugs, doctors can use those drugs to save a patient’s life.

Indeed, doctors and companies are already offering this service to patients, or plan to very soon. They say that there are about 200 genes that can be targeted by specific drugs, and that by sequencing a patient’s tumor, they can match the patient up with drugs targeted specifically against his or her tumor. You don’t have to sequence a patient’s whole genome to read these 200 genes, which make up less than 0.02 percent of a person’s total DNA, Matthew Herper reports in Forbes. So the cost of performing this test is close to $4,000 – far less than the sum Jobs paid.

So why, given the enormous power of this technique, didn’t it save Steve Jobs’ life?

Researchers have found that most cancers contain a mess of many different mutations. One study of 24 patients with pancreatic cancer, for instance, found that each patient carried his or her own unique set of about 63 genetic mutations. It’s not easy to tell which of these mutations cause a patient’s cancer, and which are just along for the ride, so it’s hard to predict how well a drug targeting any of these mutations will work against a tumor.

Second, there may not be a drug available that targets the mutations carried by a patient’s particular tumor.

Third, cancers mutate as they spread throughout a patient’s body, and constantly develop new mutations. So they can quickly outrun targeted treatments.

So sequencing-guided cancer treatments are not necessarily cures – at least not yet. Cancer genomics is still in its infancy; the field has enormous potential. Don’t get me wrong: genome sequencing can and will help more and more people live better, healthier lives. The progress that scientists and doctors in this field are making is breathtaking.

It’s even possible that Jobs himself contributed to this progress by allowing his data to be used in research studies. Scientists at Johns Hopkins University in Baltimore, Maryland – one of the institutions involved with studying Jobs’ cancer genome, according to Isaacson – have published genetic studies of the type of tumor that claimed Jobs’ life, but wouldn’t tell me whether he participated in the studies, citing privacy issues.

But if Jobs’ main motivation for sequencing was to save his own life, his story underscores the fact that stories about the failures of any medical intervention are precisely the ones that we are least likely to hear. It’s understandable; no one wants to publish a paper or give a TED talk about an experiment that doesn’t work. But nothing in medicine or science works 100 percent of the time.

The fact that we do know about Jobs’ cutting-edge treatment – and its limits – is a credit to him and to his family, and shows just one more way that his unique path in life will continue to influence all of us even after his death.

***

Image credit: Vectorportal.com.

Comments

What’s that quote?

Science is first of all about discovery (the first word on
everything). But the more science knows, the more it realizes what it doesn't know (the last word on nothing). Curiosity and humility: the human condition.

Our Readers

What’s on the Banner?

It's an illustration from a display at the Field Museum in Chicago. It shows the different types of symmetry of life forms on Earth.

Highly Recommended!

 

The cutting-edge account of the latest science of autism by Temple Grandin and LWONer Richard Panek Order now!

 

Award-winning science writers (including 3 LWONians and 5 LWON guest posters) with 300 years of combined experience tell you everything they know about the craft, culture & commerce of the profession. Order now!

Blogroll

• Bad Astronomy
• Bioephemera
• Centauri Dreams
• Cocktail Party Physics
• Cosmic Variance
• Deep-sea News
• Digging the Dirt
• Ecogirl & Cosmoboy
• Ecotone
• Elfshot: Sticks and Stone
• Generation Anthropocene
• Laelaps
• NeuroTribes
• Not Exactly Rocket Science
• Only Human
• Rogue Classicism
• Speakeasy Science
• Spotty Dog
• Surprising Science
• The Loom
• The Sieve
• Tooth and Claw
• Universe Today
• Worldwatch Blogs