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Lynne Eldridge MD

What Does it Mean if I Have an ALK Mutation?

By June 30, 2013

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Trying to understand a diagnosis of lung cancer was hard enough in the past. The first weeks following a diagnosis were like taking simultaneous crash courses in foreign languages you never wanted to learn.

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But now, as we are discovering and finding drugs to treat mutations in cancer cells, an extra course in molecular biology and genetics is thrown on top of that already maxed out load - whether or not you had the biology prerequisites in college. Terms such as EGFR, ALK, and KRAS may be swimming in your head like one of those word puzzles in the Sunday paper. If it's any consolation, the very researchers who are now specializing in some of these "mutations," were oblivious to their existence just a few short years ago.

If you've been told you have an ALK mutation and that there is a treatment available, it's likely that most people will have no idea what you are talking about. Even your friends and neighbors and their friends and neighbors who have lived with lung cancer may have never heard the term.

Why?

Until 2007, we weren't even aware that the mutation existed. And since the mutation (more accurately, an EML4-ALK fusion gene) had yet to be discovered, there certainly wasn't a treatment available. Yet now there is, and in this day and age when it seems to take forever for a new treatment to be born, it only took 4 years from discovery to treatment. In 2011, Xalkori (crizotinib) was approved.

Why is this exciting? Studies have found that people with advanced lung cancer who test positive for the ALK mutation, have a response rate of over 50%, with progression-free survival of 7 to 10 months. This may not sound terribly earth-shattering, but it's important to note that the people studied had already had traditional chemotherapy for lung cancer. Further chemotherapy only provides around 3 months of progression-free survival on average, with a response rate of 10%.

Unfortunately, resistance to the drug develops for almost everyone after some time. But new drugs are being studied in clinical trials for people with the EML4-ALK fusion gene for those who become resistant.

This mutation is only present in 5% or less of people with lung cancer. It's often found in younger people, women, people of East Asian ethnicity, and those who have never smoked or smoked lightly. And it's almost always found only in people with the type of non-small cell lung cancer known as lung adenocarcinoma.

Learn more about ALK positive lung cancer, who should be tested for the mutation, and treatment options:

Photo: National Cancer Institute, Bill Branson (photographer)

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