Genetic Marker Linked to Breast Cancer Researchers have discovered a genetic marker that, if present, indicates an increased risk of developing breast cancer. Women with the variation in their DNA are 1.4 times more likely to develop breast cancer during their lifetimes than women without the marker.
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Genetic Marker Linked to Breast Cancer

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Genetic Marker Linked to Breast Cancer

Genetic Marker Linked to Breast Cancer

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Up next, breast cancer news. Now, women with a family history of breast cancer can be tested to see whether they have the breast cancer genes. We've talked about this before. They are the BRCA1 and the BRCA2. And if they do have the genes, their risk of getting breast cancer is much greater than women without those genes. But those genes don't really account for all the cases of hereditary breast cancer, so scientists continue to search for other genes linked to the disease. And this week, a team of scientists has found another genetic marker that increases a woman's risk of getting breast cancer. They report the results in this week's issue of the proceedings of the National Academy of Sciences. One of the study's lead authors is here to talk about what they have found and what it means for the diagnosis of the disease.

Ken Offit is the chief of the Clinical Genetic Service at Memorial Sloan-Kettering Cancer Center here in New York.

Welcome back to the program, Dr. Offit.

Dr. KEN OFFIT (Chief, Clinical Genetic Service, Memorial Sloan-Kettering Cancer Center): Hi, Ira. How are you? It's been a while since we spoke, and we're continuing to make progress.

FLATOW: Well, let's talk about how - what you discovered and how it's different from the typical BRCA1 and 2 genes we've heard about before.

Dr. OFFIT: Well, as you correctly pointed out, you know, it's been about a decade that we've had these BRCA genes and we use these tests every day now in our routine practice, testing individuals that have family histories of breast cancer. But we've noticed along the way that there are probably half of families, maybe even two-thirds of families with lots of cases of breast cancer that don't have these BRCA mutations. And so we and other groups have been working over the past year or two to find other markers that indicate a risk for breast cancer. And now utilizing this new genome technology, we've been able to start to find a few of these.

FLATOW: Mm-hmm. So there are genetic markers. What makes them different?

Dr. OFFIT: Well, what's different about BRCA, here we were talking about relatively rare genetic markers, but if you had one of these, your risk would be very greatly increased, and you've, you know, we talked about this on the show in the past, sometimes women would even do a preventive removal of their breasts or ovaries because the risk could be 20 to 50 times increased.

What we're talking about now are a whole different type of a genetic marker. Instead of being rare, these things are amazingly common. Up to 20, 30, 40 percent of the population may be carrying these markers in some cases. But if you do have it, now your risk is - instead of being increased 20 or 50 times, your risk may only be increased 1.2 times. If you follow that, Ira, it's a very, very modest increase of risk, but it's very - it's significant.

FLATOW: It is.

Dr. OFFIT: And we've looked now in thousands of individuals, and we and a number of groups have found really about four or five of these markers that appear to account for some of this cancer that we see clustering in families.

FLATOW: So then how do you deal with it once you find that kind of marker that's just a slight risk?

Dr. OFFIT: Well, you know, there are two parts to this, you know, and I wear two hats. You know, on the one hand, you know, I have my laboratory meetings and I talk to our PhDs and our basic scientists and, of course, they and we are very excited that using these new genomic scanning techniques, we found these genes. These are not genes that turned up because we were looking at breast cancers or kind of honing in. This came because we were looking very broadly using this genomic technology, so this is exciting because we now have new genes associated with very common human cancer. We hope, in the end, to know the function of the genes, the proteins encoded, and this gives a promise for the future for better therapies. And, you know, we now are beginning to see therapy sort of directed, targeted to these genetic defects.

So on the basic sciences side, it's very exciting. But wearing my clinical hat, if this was a test that I would be offering to a family of a patient, I wouldn't be so encouraging of them to even want to know this information because the first question they're going to ask me is, well, what do I do about it.


Dr. OFFIT: And it - I think the risk here - just to put it in perspective, Ira - if a woman has a child older than the age of 35, you know, the later that you have children, the more you increase your breast cancer risk, you'll increase your risk about the same amount as if you had one of these genetic markers.

FLATOW: So then what good is having a genetic - or knowing the genetic marker then? If there's just a slight increase in risk and you don't want to worry women?

Dr. OFFIT: Well…

FLATOW: That's what I'm hearing you saying. I don't want to worry women about such a small increase.

Dr. OFFIT: Well, you know, I - you have to sort of take the baby steps before you can take the big steps. I think that for those of us who are doing this work, we really do believe that this is just the beginning of a process of uncovering probably dozens if not hundreds of these low risk markers. And, Ira, it's not just breast cancer. It's colon cancer. It's prostate cancer. It's adult onset blindness. It's diabetes. Many of these common, human conditions we do believe in the next several years, we will be able to predict with much greater accuracy than we are now doing with these single tests that account for a very small risk. I think that we'll be going into the office in another, who knows, five years, 10 years in that span and you'll be doing hundreds of hundreds of these markers, getting an entire genome scan to more precisely understand your risk.

But this is the beginning because using these technologies, we've now pinpointed a number of these low risk markers, not only for breast cancer, but also for other common cancers. So it's too early to mark it and to, I think, go in to the clinic and expect to use these single tests. But on the other hand, I think this is the beginning of a very exciting, new line of research in genetics and cancer.

FLATOW: I'm glad you went down that road a bit because, you know, once this news is out, the first thing that people are going to want to rightly know is, should I go to my doctor and ask to have this new genetic marker test?

Dr. OFFIT: Well, of course, we're in precisely this situation because women who have come here to see us or participated in our research studies - and I have to tell you - have been extremely generous of their time and effort and are very highly participatory. And we have to now think, well, is this information that would be helpful or useful to them at this point. And I have to say quite honestly that no, I don't think so because I wouldn't change their timing of doing a mammogram or an MRI exam and I certainly wouldn't do a surgery based on this information.

But on the other hand this is an advance. It's a significant first step to finding probably these panels of dozens or hundreds of these markers that will enable you to change something in terms of your prevention and detection.

FLATOW: A question here from Second Life - a good one. Do the same markers for women apply to men? Do you find them in men and maybe has some - maybe they have an indication for some other kind of disease?

Dr. OFFIT: Well, that's certainly been the case so far. It's probably not as well known among the general communities but, for example, when we do the BRCA testing, it often comes as kind of a rude surprise to some of the men that they have an increased risk of prostate cancer because they're carrying a BRCA mutation that's associated with breast cancer in their daughters or in their sisters. And so there does appear to be this crossing over of different cancer types.

Another example is a marker on chromosome 8 that is currently getting an incredible amount of scrutiny. This appears to be associated not only with breast cancer in women but also with prostate cancer, again, and colon cancer. So it is interesting and fascinating that some of these markers are crossing the boundaries of gender and disease types.

FLATOW: All right. Let's take those two markers in particular. Are they then part of a routine screening, for example, in an annual checkup?

Dr. OFFIT: So it's the same question of exactly the same question of numbers here - each of these markers that I'm talking to you about - the risk over the lifetime is on the order of 1.2, 1.3. And remember again that point of comparison, the breast cancer markers and there are other genes, by the way, as you know, Ira, we spoke on your program some years ago about colon cancer. We found a mutation that increased the colon cancer risk by 20 to 50 times.

FLATOW: Right.

Dr. OFFIT: These markers are not those markers. They're still very subtle and I don't personally believe and I wouldn't have a test that would give such a small element of risk increase. Live your life in a healthy way, get your colonoscopies, get your mammographies. The result of the test like this really is not going, at this point, to impact on that type of behavior yet.

FLATOW: Talking about cancer marker genes this hour in TALK OF THE NATION: SCIENCE FRIDAY from NPR News. I'm Ira Flatow talking with Dr. Ken Offit, chief of the Clinical Genetic Service at Memorial Sloan-Kettering Cancer Center in New York.

So you're just beginning to collect these but people - are people going to be willing to wait do you think, you know, until they can get or learn about these? Or let me give you the corollary to the question: When will the insurance companies will be willing to pay for these kinds of tests, I guess, which is a bigger question.

Dr. OFFIT: Well, you know, I've been talking a lot about this. My basic sciences colleagues, and I should point out that my good colleague that I did this work with, Dr. Bert Gold at the National Cancer Institute who I've worked with for years also is very clinically tuned and he's also raised this question as we've spoken about this.

We think that the insurance companies ultimately are going to take a very progressive view about all of this testing because from the point of view of the insurance company, ultimately, a life saved is a far, far better investment, if you will, the costs of illness are enormous relative to the cost of prevention. But yet we are not to the point yet where we would say to someone, don't get you're colon cancer screening because your test is negative.

There's a - I heard this just in England at a scientific meeting and one of my colleagues there at Cambridge said that they had a case where someone had a prostate cancer test, his father had prostate cancer, his prostate cancer or genetic test was negative and someone actually told him not to worry so much about getting his PSA. That's exactly the sort of thing that we're worried will happen. People want to get tests very often to get good news. This is not the kind of test that should give you that level of relief.

FLATOW: Mm-hmm. Let me go quickly to Catherine(ph) in Milford, Delaware.

Catherine, hi.

CATHERINE (Caller): Hi.

FLATOW: We just have about a minute left. Go ahead.

CATHERINE: I have question. My sister was diagnosed at 46 with fourth-stage breast cancer and died four years later. I was also diagnosed with early stage breast cancer. We've been followed by the Fox Chase Cancer Center in Pennsylvania, genetically, and we have - both of us had the same mutation on a BRCA gene. And it seems interesting to me that the new discoveries we're talking about today are about a much less significant genetic mutation. I'm not quite sure if I'm correct about that, but I'm still waiting to see what my daughter's genetic chances are to actually, you know, be a high-risk candidate for breast cancer. She also unfortunately has a male, a grandfather on my husband's side, that also had breast cancer, so it's a very high-risk situation. I just don't know, you know, he talked about…

FLATOW: So you have - Catherine, do you have a question because we're running out of time.

CATHERINE: Yeah, the question is, you know, what is the difference between genetic mutations on the BRCA gene and the chromosome 8 defect that you're talking about?

Dr. OFFIT: Well, very quickly to Catherine, the exciting thing and that I'm working very hard on for families like yours, many of the same markers that we're finding now appear to modify the risk even in the setting of having these BRCA mutations which is fascinating and we're running an international study, so maybe in the next, you know, period of time, five to 10 years, we'll be able to do additional tests in addition to the BRCA test that you've had to say to you and your daughters and family that your risk may be more for, say, ovarian cancer, more or less for ovarian cancer. So we're using the same technologies even in the setting of having these BRCA mutations and I know that there's an active research program at Fox Chase where you can collaborate with them to these kinds of studies. This is the genomics now not the genetics which is going to give us more information.

FLATOW: Can you stay with us another - a few minutes, Dr. Offit?

Dr. OFFIT: Sure thing.

FLATOW: All right. We're going to take a short break, come back and talk more with Dr. Ken Offit about the breast cancer and take your calls, so don't go away, we'll be right back.

I'm Ira Flatow. This is TALK OF THE NATION: SCIENCE FRIDAY from NPR News.

(Soundbite of music)

FLATOW: You're listening to TALK OF THE NATION: SCIENCE FRIDAY. I'm Ira Flatow talking with Dr. Ken Offit of the Memorial Sloan-Kettering Cancer Center in New York, about some new genetic gene markers that have been discovered.

One more question, Dr. Offit, we've been talking a lot about the future. It seems like we are about to enter this new world of genetic markers and possibly, you'll be collecting hundreds of them, do you think, that kind and on that level?

Dr. OFFIT: Well, you know, it is extraordinary, Ira, that we're at this point now where we're thinking of these common disorders as I was mentioning. You know, all of the cancers that we're talking about, breast, colon and prostate and some other conditions that I've mentioned such as adult onset blindness and perhaps eventually Alzheimer's disease where we will be doing panels of markers probably, not hundreds; they're not thousands but tens to hundreds of thousands of these markers that will be useful.

Right now, I think, it's premature. You know, some of this is being attempted commercially. I think, it's too early because the research is still in progress. You know, our paper is coming out next week. You know, it's not time yet but eventually, there's no question, in my mind, that as we go into our physician's offices in the future, we will be getting hundreds of thousands of marker tests and we'll probably change our behaviors in some way based on those results.

FLATOW: Well, so you've now got the region of these genes, is it a next step then to hunt for the genes within that region?

Dr. OFFIT: Absolutely, and that's where we are. We have two candidate genes in that region. We're working with the laboratory of Mike Dean at the NCI, Bert Gold, my colleague that I mentioned, as well as colleagues here in Sloan-Kettering to zero in on these culprits. One of the genes actually is sort of suspicious, it's a family member of genes that we know clearly are involved in breast cancer.

And as you've seen over the course of this decade, we have gone from basic research to using these tests diagnostically and in the case of Herceptin which many of your listeners will know if they have been treated, we've actually developed therapeutics based on some of this basic research. It all ultimately is leading to that type of advance.

FLATOW: Well, I want to thank you for taking time to be with us today, Doc.

Dr. OFFIT: Thanks very much, Ira. Talk to you again.

FLATOW: Oh, as always. Ken Offit, who is chief of Clinical Genetic Services at the Memorial Sloan-Kettering Cancer Center.

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