Question: What Are Cancer Markers?

[Guest Bodie]

Recently, on Circle of Grey, someone posted that Dr. Couto gave a speech at Dewey and said OSU was shortly going to recommend artimisinin for all greys with cancer and cancer markers.

 

So what are cancer markers and how do you determine if your grey has them?

 

Bodie is already on artimisinin with his osteosarcoma, but I was thinking of my, normally, very healthy Rainy. It would be nice to know if she had any cancer markers and get her started on artimisinin, if she did, and perhaps spare her what Bodie had to go through. Bodie and Rainy are distantly related through bloodlines (one's grandfather is the other's great-grandfather)

 

By the way, I posted the same question on COG and no one has given me an answer so far. Anyone of the very knowledgable people on Greytalk have an answer? Yes, I could email the very busy people at OSU, including Dr. Couto, and ask, but I thought I'd check here first.

[ahicks51]

Cancer markers are also known as tumor markers.

 

From the National Cancer Institute (http://www.cancer.gov/cancertopics/factsheet/Detection/tumor-markers):

 

# What are tumor markers?

 

Tumor markers are substances produced by tumor cells or by other cells of the body in response to cancer or certain benign (noncancerous) conditions. These substances can be found in the blood, in the urine, in the tumor tissue, or in other tissues. Different tumor markers are found in different types of cancer, and levels of the same tumor marker can be altered in more than one type of cancer. In addition, tumor marker levels are not altered in all people with cancer, especially if the cancer is early stage. Some tumor marker levels can also be altered in patients with noncancerous conditions.

 

To date, researchers have identified more than a dozen substances that seem to be expressed abnormally when some types of cancer are present. Some of these substances are also found in other conditions and diseases. Scientists have not found markers for every type of cancer.

 

There is a more complete discussion as to the use of tumor markers on the web page referenced above.

[Guest MorganKonaAlex]

I was hoping someone who heard Dr. Cuoto's speech would remember the tumor marker. I'm curious too.

[HopeForHounds]

I'll ask him the next time I email, which should be Wednesday. Someone PM me then and remind me, mind like a seive these days.

 

 

[RobinM]

If you are talking about fidutial markers, in the office I work at (Urology) a patient with Ca with have fiducial markers placed by our docs so when they have radiation and/or whatever surgery they chose, the markers will be located where the CA is. They know exactly where the spot (s) are.

[Guest MorganKonaAlex]

If you are talking about fidutial markers, in the office I work at (Urology) a patient with Ca with have fiducial markers placed by our docs so when they have radiation and/or whatever surgery they chose, the markers will be located where the CA is. They know exactly where the spot (s) are.

Nope, different markers. tumor markers are proteins in a blood sample. For instance, PSA is a marker used for prostate cancer. CA-125 is a marker for ovarian and some other cancers. Tumor markers are not always definitive though. They can be elevated for benign conditions. References to Dr. Cuoto's speech is the first I've heard of a tumor marker for OSA. I'm just curious what it's called. With my 2 OSA dogs, the oncologists never mentioned a marker.

[sweetdogs]

References to Dr. Cuoto's speech is the first I've heard of a tumor marker for OSA. I'm just curious what it's called. With my 2 OSA dogs, the oncologists never mentioned a marker.

IIRC, he didn't mention what it was, just that it had been found. I think it was a very recent finding (like the Thursday before Dewey) & it was found by one of the other universities doing cancer research (maybe Michigan?). He was very excited about it.

[Guest grey_dreams]

This is what I've been able to find:

 

The work is largely being done by the group of Kerstin Lindblad-Toh at the Broad Institute at MIT. This group collaborated in the effort to sequence the dog genome, which was completed around 2005-2006. They are doing a lot of analysis of dog diseases and more information about their programs is here. They've recently located a group of SNP (single nucleotide polymorphisms) that are markers for osteosarcomas. It appears that they've already got a collaboration running with a company called Affymetrix, which makes gene chips. So it seems that the SNP markers for canine osteosarcoma are on a chip that is available commercially. If this is correct, it means that a sample of DNA from a greyhound could be screened with the SNP chip to test for the presence of the markers. This information would reveal if the hound might be in the very earliest stages of a developing osteosarcoma.

[Guest MorganKonaAlex]

First, let me say that I am not a doctor. I am an engineer and did a lot of reading when I was diagnosed with cancer a few years ago.

 

I think we're talking about 2 different things here. From what I could read about the Broad Institute, it is identifying gene sequences that would predispose a dog to osteosarcoma. It would tell you if your dog had a higher chance of getting OSA but not tell you if he/she actually had it. It would be similar to BRCA1 and BRCA2 gene tests for breast cancer.

 

Tumor markers tests look for certain proteins in the blood or urine. Elevated levels of the proteins can indicate an active cancer. Generally, different markers are correlated with different cancers. As I mentioned before PSA is used for prostate cancer. A lot of times the tumor marker tests are not definitive. They can be elevated for benign reasons and not elevated for some cancers.

 

So I'm intrigued about the statement that the chip could reveal if the hound is in early stage osteosarcoma. Did I misunderstand something?

[NeylasMom]

First, let me say that I am not a doctor. I am an engineer and did a lot of reading when I was diagnosed with cancer a few years ago.

 

I think we're talking about 2 different things here. From what I could read about the Broad Institute, it is identifying gene sequences that would predispose a dog to osteosarcoma. It would tell you if your dog had a higher chance of getting OSA but not tell you if he/she actually had it. It would be similar to BRCA1 and BRCA2 gene tests for breast cancer.

 

Tumor markers tests look for certain proteins in the blood or urine. Elevated levels of the proteins can indicate an active cancer. Generally, different markers are correlated with different cancers. As I mentioned before PSA is used for prostate cancer. A lot of times the tumor marker tests are not definitive. They can be elevated for benign reasons and not elevated for some cancers.

 

So I'm intrigued about the statement that the chip could reveal if the hound is in early stage osteosarcoma. Did I misunderstand something?

 

I think you're right, if we're talking about snips here, then the chips would be used to see if your dog had a predisposition for osteo, not if he had an active cancer. Either one sounds very promising though, so I'm anxious to hear more!

[sweetdogs]

I think we're talking about 2 different things here. From what I could read about the Broad Institute, it is identifying gene sequences that would predispose a dog to osteosarcoma. It would tell you if your dog had a higher chance of getting OSA but not tell you if he/she actually had it. It would be similar to BRCA1 and BRCA2 gene tests for breast cancer.

I think this is what Dr. Couto was talking about. He mentioned about the dog genome mapping project & that this would be a way to tell if a dog (or a bloodline) is predisposed to OSA. I remember thinking that I wouldn't really want to know. And that this info needed to be used by greyhound breeders to stop breeding dogs with this predisposition. He felt it was a good thing, another step in the journey to eliminate cancer.

 

[Guest grey_dreams]

First, let me say that I am not a doctor. I am an engineer and did a lot of reading when I was diagnosed with cancer a few years ago.

 

I think we're talking about 2 different things here. From what I could read about the Broad Institute, it is identifying gene sequences that would predispose a dog to osteosarcoma. It would tell you if your dog had a higher chance of getting OSA but not tell you if he/she actually had it. It would be similar to BRCA1 and BRCA2 gene tests for breast cancer.

 

Tumor markers tests look for certain proteins in the blood or urine. Elevated levels of the proteins can indicate an active cancer. Generally, different markers are correlated with different cancers. As I mentioned before PSA is used for prostate cancer. A lot of times the tumor marker tests are not definitive. They can be elevated for benign reasons and not elevated for some cancers.

 

So I'm intrigued about the statement that the chip could reveal if the hound is in early stage osteosarcoma. Did I misunderstand something?

 

Sorry to get back to this thread so late, Kris. I also am not a doctor but my training is in biochemistry cell biology and biophysics. Here is a seminar presentation from late 2006 on the SNP chips by a member of the Michigan group. It describes the work in more current detail than the information on the Broad Institute site. My understanding of this, is that the 3-4 regions of SNPs they have identified as linked with osteosarcoma show 100% linkage. This means, if the greyhound has these SNP markers, the chances that they will go on to develop a tumor are really really high (something on the order of >90-95% certainty). It takes quite some time for a tumor to form and become invasive - from intial cell cycle disruption, to cell proliferation, to tumorigenesis, to cell migration and invasion of distant sites. I was thinking that if a dog is found to have these SNPs, it could be treated with some of the number of non-toxic compounds that are known to inhibit the growth rate and invasiveness of any potential tumors (eg. antioxidants), in order to avoid/limit tumorigenesis at the outset. Also, if the dog does have these SNPs, you could screen them regularly for osteosarcomas, and then catch any potential tumors and begin treatment at the earliest possible times. But this is only my take on reading the descriptions of the work, and thinking about how it could be applied in a treatment program. I hope that Dr. Couto or Dr. Freeman would be able to explain it better.

[turbotaina]

So then if that's the case, Dr. Couto is recommending that dogs with such markers be treated prophylatically with arteminisin? Interesting. Must go see his next speech. I didn't go at Dewey, but I wonder if he'll be doing the fundraiser in Fredricksburg again in -08.

[Guest MorganKonaAlex]

Sorry to get back to this thread so late, Kris. I also am not a doctor but my training is in biochemistry cell biology and biophysics. Here is a seminar presentation from late 2006 on the SNP chips by a member of the Michigan group. It describes the work in more current detail than the information on the Broad Institute site. My understanding of this, is that the 3-4 regions of SNPs they have identified as linked with osteosarcoma show 100% linkage. This means, if the greyhound has these SNP markers, the chances that they will go on to develop a tumor are really really high (something on the order of >90-95% certainty). It takes quite some time for a tumor to form and become invasive - from intial cell cycle disruption, to cell proliferation, to tumorigenesis, to cell migration and invasion of distant sites. I was thinking that if a dog is found to have these SNPs, it could be treated with some of the number of non-toxic compounds that are known to inhibit the growth rate and invasiveness of any potential tumors (eg. antioxidants), in order to avoid/limit tumorigenesis at the outset. Also, if the dog does have these SNPs, you could screen them regularly for osteosarcomas, and then catch any potential tumors and begin treatment at the earliest possible times. But this is only my take on reading the descriptions of the work, and thinking about how it could be applied in a treatment program. I hope that Dr. Couto or Dr. Freeman would be able to explain it better.

 

That was the information I was looking for. Thank you.

 

Now we need better screening tests. :-)

[Guest grey_dreams]

That was the information I was looking for. Thank you.

 

Now we need better screening tests. :-)

 

Yes, better screening tests are a must. I did some more searches, and found a couple of interesting articles. One study by a group in Florida ran a comparison to identify age and site where OSAs were most likely to occur. The found that in greyhounds, disease leading to diagnosis was most prevalent around 10 years old. The tumors were often found on the proximal end of the femur. Another study looked at bone metabolites as possible markers for tumors, and found one that seemed to correlate with diseased versus healthy bone.