# lump



## janjiie (Sep 29, 2009)

Just noticed that one of our new mousies has a lump about hte size of a baked bean on her right side. It has a certain amount of movement under the skin and is fairly firm when squeezed and doesnt seem to cause her any pain.

Anyone any ideas, she is one of the kids immediate favourites, is it likely to be treatable? If not is it advisable not to breed from her?

cheers jan
~C:>


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## Kallan (Aug 16, 2009)

How old is it?

Lumps in mice tend to either be tumours, abscesses or cysts. If it's freely movable it should be fairly easily to surgically remove if you find a vet willing to try.

Other option is to leave it if it's not bothering her. How old is she?


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## moustress (Sep 25, 2009)

Meeces, especially females, are prone to cancerous tumors, usually mammary tumors. One can reduce the incidence of this by eliminating corn and corn peoducts from their diet.


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## janjiie (Sep 29, 2009)

Thanks for that, have discovered another of the females we got has the beginnings of a small lump too.

Is it genetic? are we still able to breed from these girls, the lumps dont seem to bother them.


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## moustress (Sep 25, 2009)

Breeding does when they are still young, like three months old, can help to reduce the chances of mammary cancer. I usually do two litters back to back (yes, I know know many breeders frown on that) which eliminates the estrus cycling that stimulates the occurrence of estrogen sensitive tumors. As a matter of fact, one can often stimulate a remission by allowing the doe to be impregnated.


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## janjiie (Sep 29, 2009)

that's brilliant news! as always with sods law it's the prettiest with the lumps so they were the ones we reallly wanted babies from!

ta!

~C:>


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## SarahY (Nov 6, 2008)

Cancer can be a genetic family trait just like with people, so you need to think carefully about whether you want to pass that on to her daughters. I'm sorry if that sounds mean, I really don't mean it to be, but personally I would never breed from an animal that had a tumour, and if you're breeding pets then you want them to live long, healthy lives.

Sarah xxx


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## moustress (Sep 25, 2009)

I will repeat what I said before about the importance of eliminating corn from the diet you give your mousies. Yes, the tendency may run in the line, but eliminating corn will reduce to incidence of tumors to near zero in any line. The other factors is fat in the diet. By limiting fat to the minimum required for good health, which is, if I remember correctly is 11 % of the total number of calories in the diet, you can reduce it even more. I also am starting to think that peanuts and sunflower seed are almost as bad corn. I experimented and put food grade peanuts and sunflower seeds back my rodents diet over last winter, and had a streak of does get tumors over a couple of months. I now allow sunflower meats (not in the shell) purchased in the bulk section of the supermarket once or twice a week, and no peanuts at all. My last doe with a tumor died a few days ago; she survived for many months without the tumor getting any larger. I think that part of the problem is using seeds that are packaged for wild bird food which have a greater allowed level of food-borne fungus and mold, plus contaminants in the mix itself. With the exception of the corn-free kibble, I don't feed my mousies anything I wouldn't eat myself. (I am thinking of giving them some crickets; I'd probably eat crickets if I was starving. I've eaten bugs before.)


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## SarahY (Nov 6, 2008)

As I mentioned in another thread, I don't feed corn and haven't for years but have still had instances of tumours in most of my pet shop/rescue mice and rats when my exhibition rats and mice have had no tumours. Mine don't get sunflower seeds or peanuts in their diet either. I don't know what pet shop animals are like in America, but over here a great deal of them are extremely prone to tumours whatever you're feeding them.

I'm not trying to say you're wrong because I've also read plenty to back up the corn is bad theory, but there's no evidence anywhere that cancer is caused entirely by diet. I just thought the OP should be aware that any babies from a doe with cancer could have cancer themselves. It's better to have all the facts before a decision is made!

Sarah xxx


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## moustress (Sep 25, 2009)

I didn't mention that I also give my mousies purified water from the supermarket that is treated by reverse osmosis which makes it just about the same as distilled water, very, very pure. It's pretty inexpensive, and I wouldn't use tapwater for myself in anything I eat or drink. My does used to get tumors with what seemed to me high frequency before I changed the diet and the water. Stress can contribute to a higher incidence of cancer as well. I was surprised myself when my mousies stopped getting tumors. I don't mean to harangue you endlessly about this; I'm sorry you have a problem in this matter. Let us not even speak of this again. :dots


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## janjiie (Sep 29, 2009)

thankyou all for your advice, information is the best way to go!

I hadn't considered things like drinking water, because of course the tap water is treated with things like fluoride and chlorine which just wouldnt be found in puddle or rain water.

These are my first mousies and they came the way they are, so anything I can do for prevention etc is a help.

When I have a go at breeding hopefully I'll have got things a bit more sorted and any babies should be as healthy as they can be and get the best of starts for a long healthy life!

THanks all

Jan


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## Cait (Oct 3, 2008)

I give my mice tap water and I drink it myself every day - there is nothing wrong with the water where I live so I see no problem in doing so. My mice also eat sunflower seeds but not corn specifically (though it may be a small proportion of the ingredients in other foods I use) or peanuts (no nuts because I am very allergic) and my mice have a low incidence of tumours. The longer I have bred a line the less tumours they have, presumably because I have selected the healthiest and best to breed from. However they've always had a variation of the same diet during the time I've been breeding.

As for the question about whether you should breed these does: I'd say first of all you need to find out what the lumps are. If they are abscesses they can be drained and don't affect breeding capacity. If they are tumours I wouldn't breed from the does - they may not even survive long enough to raise a litter (minimum of 7 weeks - long enough for a tumour to become very large on a mouse). I think you said they are favourites of the children - I'm sure they'd be devastated if they lost not only their pet but all her babies too, regardless of our opinions of whether they can/should be bred.


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## WillowDragon (Jan 7, 2009)

I agree totally with Mousebreeder... I personally wouldn't breed from any mouse I suspected had cancerous lumps.

And if mice are anything like humans, the hormone changes in the body from pregnancy can excelerate the growth of tumours ALOT and it would effect the lifespan dramactically.

Willow xx


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## moustress (Sep 25, 2009)

Pregnancy actually inhibits or stops the growth of mammary tumors by eliminating the estrus cycle during which the production of estrogen is lowered considerably. Estrogen stimulates the growth of mammary tumors.

I still would not recommend breeding a doe with lumps that are not mammary tumors. Mammary tumors are usually found sticking out on the underside of the mousie.


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## JanA (Jun 8, 2009)

Could someone define what they mean by 'corn' please - depending on what country (or even what part of a country you come from it can mean different things). Do you mean wheat or maize?

I am concerned as I seem to have an absolute spate of tumours (lumps on underside, presume mammary tumours not cysts/abscesses) in my Longhaireds. 
Mice were cleaned out in daylight five days ago - noticed two with tumours then but have spotted at least another four or five mice with problems tonight which I didn't see when I cleaned them out. This is a line of mice that I have bred for 6-7 years and they have had a very low incidence of tumours.

I have cut down a bit on the breeding this winter and there may be more maiden does kicking around than I would have had previously.

What would cause such a sudden upsurge in tumours though? Could there be a viral component to it?

Their feeding has been a bit variable this winter. For years they had guinea pig mix with other odds and ends added (sunflower seeds, millet etc) but recently we changed our guinea pigs food to one that is not suitable for the mice (alfalfa based pellets) and so the mice have had a bit of chopping and changing while I look for a mix that I like for them.

I will be cleaning out again tomorrow in daylight and will have a real inspection of everyone to check for early lumps. As far as I can see (in rather low level of artificial light in the shed tonight) two of the big boxes of Longhaireds are involved but not my Varigateds or Brindles.

I'm really puzzled by the speed that this seems to have 'spread' through the stock - which, of course, could implicate feed. There must however (unless I find other breeds with problems tomorrow when I clean out)be a 'predisposition' element to it, if only one breed is affected.


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## WillowDragon (Jan 7, 2009)

Moustress means maize.

its practically impossible to find food over here that doesn't contain it, unless of course you mix the complete diet entirely yourself and don't include it.

W xx


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## moustress (Sep 25, 2009)

Making your own food can save a lot of money as well as improve the health of your critters.


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## Kallan (Aug 16, 2009)

JanA said:


> I am concerned as I seem to have an absolute spate of tumours (lumps on underside, presume mammary tumours not cysts/abscesses) in my Longhaireds.
> Mice were cleaned out in daylight five days ago - noticed two with tumours then but have spotted at least another four or five mice with problems tonight which I didn't see when I cleaned them out. This is a line of mice that I have bred for 6-7 years and they have had a very low incidence of tumours.


Definitely not abscesses from fighting?


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## SarahC (Oct 3, 2008)

From Wikipedia, the free encyclopedia

Mouse mammary tumor virus

Species: Mouse mammary tumor virus

Mouse mammary tumor virus (MMTV) is a milk transmitted retrovirus like the HTL viruses, HI viruses and BLV. It belongs to the genus betaretroviruses. MMTV was formerly known as Bittner virus, and previously the 'milk factor' referring to the extra-chromosomal vertical transmission of murine breast cancer by adoptive nursing, demonstrated in 1936, by Dr. John Joseph Bittner, while working at the Jackson Laboratory in Bar Harbor, Maine. Dr. Bittner, a geneticist and cancer biologist, established the theory that a cancerous agent, or "milk factor", could be transmitted by cancerous mothers to young mice from a virus in their mother's milk . The MAJORITY OF MAMMARY TUMORS in MICE are caused by mouse mammary tumor VIRUS (MMTV).

Infection and life Cycle

Several mouse strains carry the virus endogenously, but it is also transmitted vertically via milk from mother to pup. It is contained as a DNA provirus integrated in the DNA of milk lymphocytes. The viruses become transported through the gastrointestinal tract to the Peyer's patches where they infect the new host's macrophages, and then lymphocytes.

The Mouse Mammary Tumor Virus (MMTV) has formerly been classified as a simple retrovirus, however, it has recently been established, that MMTV encodes an extra self-regulatory mRNA export protein, Rem, with resemblance to the Human Immunodeficiency Virus HIV Rev protein, and is therefore the first complex murine retrovirus to be documented

MMTV codes for the retroviral structural genes and additionally for a superantigen. This stimulates T lymphocytes with a certain type of V beta chain in their T cell receptor, which in turn stimulates B cell proliferation increasing the population of cells that can be infected. During puberty, the virus enters the mammary glands with migrating lymphocytes and infects proliferating mammary gland epithelial cells.

As a retrovirus the mouse mammary tumor virus (MMTV) is able to insert its viral genome in the host genome. The virus RNA genome is reverse transcribed by reverse transcriptase into DNA. This DNA intermediate state of the virus is called the provirus. When the virus DNA is inserted inside or even near an oncogene, is able to change the expression of that gene and cause cancer [7]. The viral genome is able to cause cancer only if it alters the expression of an oncogene. If the viral genome is inserted in a 'silent' region of the host genome then it is harmless or may cause other diseases. In lymphocytes a T-cell leukemia was shown to occur.

When the virus genome is inserted inside the host genome it is then able to transcribe its own viral genes. In F. U. Reuss and J. M. Coffin (2000) experiments it is mentioned that the expression of the virus genome is activated by an enhancer element that is present in the U3 region of the long terminal repeat of the genome [8]. In addition the expression of the genome is activated specifically in the mammary gland cells [8]. Estrogen is able to further activate the expression of the viral genome [7]. The expression of sag gene which is present in the provirus is responsible for the production of a superantigen.

MMTV can be transferred either through an exogenous or endogenous route. If the virus is transferred exogenously, it is passed from the mother mouse to her pups through her milk. [9]

Alternatively, pups can be infected vertically through endogenous infection, inheriting the virus directly from their mother in the germline. Mice that become infected in this way have higher rates of occurrence of tumors. A retrovirus is endogenous to its host once the proviral DNA is inserted in to the chromosomal DNA. As a result mice with endogenous MMTV have the virus's DNA in every cell of its body, as the virus is present in the DNA of the sperm or egg cell from which the animal is conceived.


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## JanA (Jun 8, 2009)

Kallan said:


> Definitely not abscesses from fighting?


Probably not. 
It was something I had considered as I also breed cavies and (with the exception of abscesses in throat) fighting injuries are the common cause of abscesses. I am going to clean the mice out today and so I am going to have a closer look at the position of tumours but I would have expected some to be on the top of the body if it was fighting.


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## JanA (Jun 8, 2009)

Thanks SarahC.
I've just had a look at the full Wikipedia article. The thought of MMTV being implicated in human cancer is enough to make anyone shudder.

I must admit that I am extremely cautious about hygiene when handling mice with tumours just in case there is any sort of virus involved. Certainly puts you off nibbling a sandwich at the same time as handling mice....I wonder if everyone washes their hands before going into the canteen at mouse show !!!!! Maybe when everyone sits down to lunch... but perhaps not for the quick cup of tea and biscuit?


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## moustress (Sep 25, 2009)

Thanks for the extensive report, Sarah. Transmission by milk makes this a serious problem for mouseries of any size, but worse for those of us with large operations. Of course, any virus would pose a problem like this one. I'm curious if any common rodent diseases, other than Hanta virus, has been tracked through unexpected vectors. I'm also curious about weather related stress and rodent mortality; it seems like I have die-offs whenever the weather changes abruptly.

I'm not that worried about hanta; I rarely get meeces from outside the upper midwest area. Retroviruses are freaky forms of life that create incredible machinery, and the way they mutate is beyond belief! If we were to look for an alien invasion on earth, we might well have a good look at these tinier forms of life for a clue or two. Prions are are even more interesting. Perhaps prions are the ultimate stealth life form. Just a tiny fragment of innocent looking genetic material; unbelievably clever at hiding.


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## SarahC (Oct 3, 2008)

just copied and pasted no hard work from me involved.I'm interested also moustress but like you also rarely have new animals and after several years of culling out animals that exhibit illness I hardly experience any.Unfortunately that hasn't actually learnt me anything either.I have bred from less than perfect animals when initially starting a breeding project as it can be difficult to get 'perfect' stock.I've just eliminated the problems when I've bred enough numbers to be viable.


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## moustress (Sep 25, 2009)

That sounds very familiar. I don't cull routinely until I have a good stock of the type I want to work on.


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## WillowDragon (Jan 7, 2009)

I'm exactly the same.


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