what does '13q14' mean?

[Lindaan]

I have seen in a few posts '13q14' mentioned as something that is positive in CLL patients. Can someone tell me what this means and is it something that shows up in a routine blood test?

[lankisterguy Volunteer]

Hi Lindaan, -

That is the best result from a specialized test called FISH (fluorescent in situ hybridization) that is used to identfy one of the 4 most common genetic deletions found in the CLL cancer cells after diagnosis.

Many people with "13q" may never need treatment or will have a long time before treatment is needed.

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If you want to read more details, you can start with this Pinned Post:

healthunlocked.com/cllsuppo...

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or here: healthunlocked.com/api/redi...

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Len

[cajunjeff]

All cancers occur when cells turn abnormal. With brain cancer it’s brain cells that turn abnormal. With Cll, it’s lymphocytes that turn abnormal. Lymphocytes are a type of white blood cell.

Cells are the building blocks of life. We have dna packed into chromosomes inside our cells that tell cells what to do. Genes are part of our dna. Cancer happens when certain genes are missing or changed.

Humans have 23 pairs of chromosomes numbered one through 23. Chromosomes have an X shape with the top two arms of the chromosomes being shorter than the bottom two. The top arm is called the “p” arm from the word “petite”. The bottom and longer arms are called the “q” arms because q follows p.

Chromosomal abnormalities that cause Cll can occur at any number of our chromosomes. The most often abnormalities are at the 11, 12, 13 or 17th chromosomes. 13q deleted means that there is missing genetic material on the long arm (the q arm) of the 13th chromosome. 17p deleted means missing genes on the short arm of the 17th chromosome.

Cll arising from a deletion at the 17th chromosome is usually worse than 13q Cll because the genes missing from the 17th chromosome are more important in fighting cancer than the genes missing from the 13th chromosome.

Chromosome abnormalities are detected with Cll using the FISH test on our blood which examines the areas where Cll is known to make the most changes. 13q Cll is the most common type of Cll and carries the best prognosis. The “14” in 13q14 Cll is the region on the long arm of the 13th chromosome where genetic material is missing. Remember that chromosomes are packed with dna and genes up and down both arms. FISH tests are not routinely done in all countries but should be done before treating. In the US at most major cancer centers the FISH test is routinely done at diagnosis and then repeated later at certain intervals because our FISH test can change over time and we can have abnormalities at more than one chromosome.

No one really knows why some of our chromosomes turn abnormal with cll. It might be genetic. It might be related to exposure certain herbicides. It might be many other things.

One goal in treatment for 13q Cll is to wipe out the 13q lymphocyte cells with deletions and spare the normal ones. Then you hope only the normal cells grow back. Treatments for Cll have gotten so good some people may experience remissions where their FISH test turns normal because no corrupted cells can be found.

Since we discussed brain cancer, and as an aside, one certain type of brain cancer has deletions at 1p and 19q. By now you should know what that means, deletions on the short arm of the first chromosome and on the long arm of the 19th.

Trisomy, the fourth type of most common chromosomal defect, occurs at the 12th chromosome but involves added material at that location as opposed to deleted genes. Down’s syndrome is as a result of an extra copy of chromosome 23. It’s called trisomy, whether at the 12th chromosome for Cll or the 23rd chromosome with Down’s syndrome because there is three (tri) pieces of chromosome where there should only be two.

Here is a longer post I wrote on FISH. I hope I have not thoroughly confused you.

healthunlocked.com/cllsuppo...

[neurodervish in reply to cajunjeff]

Great answer Jeff! Heads up that the link to your longer post did not hyperlink.

[AussieNeil Administrator in reply to neurodervish]

Jeff and Neurodervish,

I've reported this bug to HU Support whereby when you edit a reply with a link, you end up with the (truncated) displayed link text, so the link no longer works. I expect this bug will be fixed early next week, as I saw the same bug a year ago and have informed HU of the date they fixed it. Jeff, your link has been restored.

[neurodervish in reply to AussieNeil]

Thanks Neil. I've waited years to see the word "concatenated" used in a sentence, so this is a great day indeed! 😍

[bennevisplace in reply to AussieNeil]

I had the same bug in a reply yesterday.

[Lindaan in reply to cajunjeff]

Thank you for that information

[pilantd in reply to cajunjeff]

Thank you very much for the excellent post. Your explanation really helped me understand what's going on.

[Paint-arty in reply to cajunjeff]

You have given a wonderful comprehensive explanation to this question. Thank you, as l have been puzzled at the significance of what those terms mean. Now thanks to you l understand them clearly.

I shall certainly be asking my Haematologist for a FISH test on my next visit, as l have never been given this information ever since l was diagnosed.

So, thank you very much.

[cajunjeff in reply to Paint-arty]

Thank you Paintarty. My understanding, and I could be wrong, that is in the UK the FISH test is not ordered at diagnosis because it is considered purely prognostic. Put another way, if your labs are holding up in watch and wait, whether you have 11q, 13q or 17p Cll now makes no difference at this point because you are not going to treat based solely on FISH results. FISH results are more than just diagnostic if we need treatment because FISH results can inform treatment decisions. For instance, if one has 17p Cll that usually rules out most chemo based treatments as 17p Cll does not generally respond to chemo. That’s why right before you need treatment, they probably would order a FISH test.

My argument in response would be that since our FISH results can change over time, getting a FISH test at diagnosis establishes a baseline for future FISH tests that can show how our Cll has evolved over time. What if our FISH started out showing 17p and then a later test showed we acquired 13q? If we only had the second test, we would never know which mutation came first. Does that make any difference? Probably not now, but I can see a time in the near future where the sequence in which we acquire chromosome mutations is important to know.

Serial FISH testing might also help us know the pace of our cll. If we had 25% 13q one year and five years later show 75% cells with 13q that might reflect our 13q Cll is not as stable was we wish.

It might come down to dollars in certain healthcare systems where they just will not do prognostic tests. Yet another argument in our favor that makes the FISH test more than just diagnostic is that as we live our Cll and make life and career decisions, should we not be entitled to know if we have to factor in the seriousness of our illness into those decisions?

Good luck getting your FISH. Sometimes the squeaky wheel gets the grease. Please let us know if your doctor will order the test. His/her hands might be tied if you do not meet whatever criteria NHS has established for the test if you are using NHS for your healthcare. Depending on your financial resources and how badly you want to know what type Cll you have, you might can see if you can pay for it privately.

[Paint-arty in reply to cajunjeff]

Thank you very much for your detailed reply. Much appreciated.

[Vlaminck in reply to cajunjeff]

Thanks for that thorough and helpful explanation.

[hhk50 in reply to cajunjeff]

Thanks, Jeff. After reading your excellent explanation, I took a look at my FISH and noted that I am 13q, which I already knew, but also that several of the other chromosomes show deletions that are "normal", i.e. within limits. Seems strange to me that chromosomal deletions can be "normal".

[cajunjeff in reply to hhk50]

The tests have cutoffs where we are considered positive or negative. If a lab uses 10% cutoff for 17p clls, that means if less than 10 % of our Cll cells show the 17 p deletion we would be 17p negative. Under that scenario, someone with 9% 17p cells would be negative for 17p and someone with 11% would be positive, even though they are very close in % of Cll cells. Some FISh tests might report small deletions like being 5% 17p positive. Others might simply report 17 p negative.

My guess is that they have these cut offs because at any moment in time, given that we have trillions of cells, it’s likely we have all sorts of irregular cells. That doesn’t mean we will get cancer. We actually have cancer repair kits built into our dna such that as we get some irregular cells, our bodies recognize it and eliminate the bad cells.

That’s why 17p Cll is challenging. One of our most important cancer repair kits is located on the p arm of the 17th chromosome. When it gets deleted, we lose part of our ability to heal ourselves.

Having a few 17p deleted cells might just be an incidental finding and they might never rise to the level of causing problems.

That leads to a discussion of clonal evolution. Very few people have 17 p Cll at diagnosis, it’s more common after treatment. That might be because if we treat to wipe out our 13q Cll, it’s possible we might have a very small underlying clone of 17 p cells that suddenly grow to fill the void. Treatments like ibrutinib and venetoclax might be less likely to result in clonal evolution, at least early on, because they are effective as to all sorts Cll.

[17Pisme in reply to cajunjeff]

As always, well done Jeff. BTW, LA is getting hit hard with the Variant, stay inside.

[cajunjeff in reply to 17Pisme]

Yes it is. An amazingly large portion of people who live around me think covid is a hoax, or it’s the same as the flu or a cold, or that masks are useless, or that masks are a govt plot, or that the govt uses vaccines to track us, or that vaccines change our dna or that some of us like wearing masks and want them to wear masks forever or some combination of the above.

It’s been driving me crazy for months. Now I just accept that most people where I live dont give a damn about covid and either don’t understand or don’t care about the risk it presents to me and their parents/grandparents. It is what it is.

[Peggy206 in reply to cajunjeff]

Your explanation is much clearer than my oncologist's. Thank you..

[CBeauty in reply to cajunjeff]

This has been a very helpful thread. Thanks CajunJeff. Your explanations from beginning to end have been great.

[Sushibruno in reply to cajunjeff]

Im impressed with your cll knowledge Jeff. I wish I had that.

[Upthenorth in reply to cajunjeff]

Wow! I understood the whole answer! Thank you!

[Hidden in reply to cajunjeff]

JeffHi, just curious if you are a teacher? Or, a writer or any trade that involves writing? Your answer is so succint & flows and as a teacher lol everying I taught the kids to do...just a side note. I know this is such a serious discussion but just wanted to say bravo for how well you educate us!!!!

Cristal

[cajunjeff in reply to Hidden]

Thanks Cristal for the very kind words. My daughter is the journalist in the family and she is really good at it. I am not a teacher but I do enjoy writing. I have to dumb science things down a lot to understand them for me. I find the science websites for children to be the best in explaining in terms I can follow. Lol.

[Hidden in reply to cajunjeff]

You're welcome!!! You must be proud of your daughter!! Be well!!!

[Big_Dee in reply to cajunjeff]

Hello cajunjeff

I was told by my Mayo Clinic H/O that 13q deletion, my only FISH result, was a good thing. Maybe or maybe not, my W&W was only 14 months, I suspect because I am 0% un-mutated. Also if resolving 13q deletions to 13q normal after B+R treatment, I should be great. Blessings.

[cajunjeff in reply to Big_Dee]

Big Dee, I think 13q Cll carries the best prognosis on average. Even if it moves a little faster than we like (I am 13q and also had short watch and wait), I still think it’s considered favorable genetics.

You should get a nice remission from the B plus R treatment. And you still will have ibrutinib and venetoclax to sequence to should you fall out of remission. That could be ten years or more of Cll control and it’s a sure bet we will have many more options then.

I do think for many, if not most of us, we are living in an era where long term control of our Cll is the norm.

[lynnsb6754 in reply to cajunjeff]

Jeff, This is the first time I've come close to understanding what my 13q deletion means, and I was diagnosed (with FISH) 3+ years ago. You are a great explainer! Thank you so much for taking the time to write the thorough description of the process that you did!

[Pkhcalif in reply to cajunjeff]

Thank you Jeff for helping clarity to many of us.

[Shaheenji in reply to cajunjeff]

HI, a very sincere effort with straightforward simple explanations. Only God Almighty rewards the people so nice like you..Hats off n salutes.God bless you, Amen

[Mend123]

Wow. That explanation is helpful and I think I now understand why having 13q plus other abnormalities is why it’s not the same as just having 13q. Can you explain TP53? And how one can have a potential 17p issue but no TP53 problem?

[gardening-girl in reply to Mend123]

There are two copies of chromosome 17, just like there are two copies of other chromosomes. As Jeff has said below, the TP53 gene, which codes for the all important p53 protein, is on the p arm of each chromosome 17, meaning that there are two copies of TP53. A TP53 mutation occurs when there is a mistake in the DNA sequence such that transcription of the gene leads to the formation of an inactive p53 protein. The mutation can occur in one copy of TP53 or in both copies.

A 17p deletion in the case of CLL means that the entire TP53 gene (along with a bunch of other genes) is missing from one or both copies of chromosome 17. The other chromosome 17 can have a normal functional TP53. If it is missing from both copies, there would be no TP53 mutation to detect because the entire gene would be missing.

It would be possible to have one chromosome 17 with a TP53 deletion (del17p), and the other with an intact, but mutant copy of TP53. In that case there would be no functional p53 protein made.

Based on data obtained from Sanger sequencing, approximately 80% of CLL patients harboring del(17p) in one chromosome also carry TP53 mutations in the second allele, meaning no functional p53.

[cajunjeff]

I am not completely sure why 17p is not always accompanied by a tp53 mutation but I can venture a guess.

TP 53 is the gene that is located on the p arm of the 17th chromosome. It’s such an important cancer fighting gene, it’s known as the guardian of our genome.

The p arm is packed with genes up and down the arm. I suppose someone could have other missing genetic material at 17p and still have the TP 53 gene intact. Usually a TP53 mutation and 17p go hand in hand.

I could be wrong. If Gardening Girl is reading, she could give a better answer. I have no real science training to know.

[NoMoRLS]

Thank you I so needed to read this. Best report in ages! I'm 13q14 deleted. Short W and W since 2017 and achieved remission 18 mos ago with 4 cycles of B/R. However those lovely B symptoms have never gone away. Nausea, bone pain, losing weight so last June we ran more tests to see if it's on tbe move. Another bmb which proved I am in remission still with no mrd. I was ecstatic but it doesn't explain the daily symptoms. And I had my 2 Moderna Vax last Jan but am being told didn't take due to ritux from chemo and my lymphocytes are just a little township not a robust city so no immunity. Back to masks and isolating. Had to retire early from teaching which financially sucks. We ran all other tests, CT, PET found some lesions on lung and pelvis but they are benign. Cll is not my 1st cancer although I suspect it was lurking around long before the breast cancer appeared I was treated for in 2013 which I'm still in remission. So 2 cancers in remission, no others, no Vax immunity, and still awful B symptoms. I have come to this site often these past 4 years and I always read excellent information. We are in an oncologist shortage in my city and I have been through 5 one's in 4 years. They keep moving away. So I try to keep up in case I fall out sooner than later.Thank you for great info. 13q14 has not been the easy form in my books as symptoms are awful and I have to dodge them all day long. Best wishes friends.