Last updated on Thursday, 14 October, 2010 18:02

Why does it appear?

For everything there is a reason. In Medicine, this is called "Pathogenesis".

Here is the million dollar question. If we knew there was a simple trigger to the formation of neoplasms, all we would have to do is to block that trigger, and there would be no more cancer, for anyone, forever. Alas, it is never that simple.

Cells can change, and indeed, they have to, in order to fullfil all of your organism's needs. Just think that inside your bones, for example, the marrow is made up of cells that are just waiting their turn to change into mature blood cells. When your body gives them the order, they differentiate into whatever type they're needed. Cancer cells are always mutated ("changed") versions of other cells that were already there before.

We do know that there are some events that will interfere with normal cell functioning for sure. Radiation, heavy metals, viruses and plasmids, amongst a few others. All of these may interfere with the genetic instructions of the cell and cause it to change in a way that was not totally foreseen. Usually, these are minor changes, and in most circumstances, the cells automatically correct the damage. And even when they don't, most of the times the changes are small enough so that they remain almost completely functional, in which case, the organism in question employs that old adage: "If it ain't broken, don't fix it".

When there is a reasonable number of these, the body may develop zones where there are transitions between normal cells and mutated ones. The changed part is usually identified as a metaplasia. Different stuff, but just that.

In other occasions, perhaps due to some deregulation of the immune system, or the presence of some growth factor, an abnormal growth of cells will occur. This is the dysplasia I glanced over in the previous page. These excendentary cells may still work alright, but there are more of them than there should be. Which means your body has to work harder to keep them alive (and happy!).

Neither of the two aforementioned situations configures a tumor, but if you add both of them there is a chance you'll get... Yep, it's cancer! Makes sense, right? If you have a bunch of cells that no longer function the right way, there's no way your body can order them to behave, and on top of that, they bring you no benefit, just a unexpected power bill (in the form of blood...). If there was just one, your immune system would most likely be able to keep it in check. On the other hand, if there were lots of them, but they still did as they were told, there would just be more of you (disfigured you, or not...)

So, in order for a tumor to arise, there has to be both a malignant mutation of some cells, and a combined inability of the organism to suppress it. Result: an uncontrolled growth of mutated cells - neoplasia.

Getting to the point at hand, a fibrosarcoma is when such an event occurs with the fibroblasts. Now, this is rare because these cells are inactive most of the time, and are associated with the healing process, which is heavily mediated by the immune system, for obvious reasons.

Typically, the highest regeneration power a species has, less are the possibilities of developing cancer. Now, humans don't have a particularly good regeneration power (think of a Hydra - the polyp, not the mythological beast - or a Salamander for prime examples) and there are several factor that contribute to this (I won't get into that subject), and our pet friends aren't much better off (a little bit better, though...). In cats, it is estimated that fibrosarcomas represent about a third of all skin and subcutaneous tissue tumors, which is way higher than in humans. It appears that their feline, competitive nature may play in this, as cats are very prone to have damage through oxidative stress (this is apparently related with the common chronic renal failure cats experience - perhaps they eat too much meat...).

A note here on oxidative stress.

Oxidative stress refers to the effect an excess of reactive oxygen species has on your system. Those "free radicals" doctors warn you about because you don't get enough exercise, well, they behave like hydrogen peroxide on your cells. It is actually so potent, that it's the weapon of choice for your immune system to lay waste to invaders. The expression "inflammation" actually refers to the burn like effect your immune system creates when it's trying to repel some pathogen, which employs these oxidative species. There are, of course, enzymes in the body to neutralize an excess of oxidative species, but if your body could balance this right, you would never get rashes (The immune system likes to employ a "preemptive nuclear assault" style strategy, instead of a more conservative approach).

Because the immune system is vital to stopping cancer in its starting stages, inflammation is heavily associated with the appearance of cancer, and indeed many other diseases. So, our furry friends are more prone to this situation, because of their bodies' response to injuries. And we foolishly compound worsening circumstances for them. One directly, and another indirectly so.

There are three different types of fibrosarcomas for cats. Firstly, there are those fibrosarcomas associated to what is called the Feline Sarcoma Virus, which is actually a mutated form of the Feline Leukemia Virus and need the latter one to function. These appear mostly a few months after kittens are born, but can appear all the way throughout their lives. They also tend to metastasize and invade surrounding tissues. Secondly, there are isolated fibrosarcomas that typically appear on older cats, many times in locations previously subjected to injury. These reoccur, but they don't tend to spread or metastasize. Lastly, the dreaded vaccine-induced fibrosarcoma, which always appear in places where there was an injection, usually of the Rabies vaccine. This one can vary from the non-metastasizing, multiple relapses type of tumor, all the way to the highly invasive, but occasionally curable ones (this is because, as a rule of thumb, the faster replicating a cancer is, the better it responds to chemotherapy).

Here you can see where can be a part of the problem, but also a part of the solution. In the vaccine-associated fibrosarcoma, it is not the antitoxin that is injected that can trigger the tumor, but rather the coadjuvant solution it is injected with. The coadjuvant solution exists to enhance the immune response of the organism so that, even though it is only a weakened or deactivated version of the virus, the immune system can effectively address it and develop antigens for it. It is there to deliberately cause an irritation. Now, this isn't normally bad. In fact, nearly all vaccines use this method. You wouldn't inject a cat with a live version of the Rabies virus, right? There seems to be no natural immunity to Rabies in either cats or humans, so it has to be done this way. The real problem is with the nature of the coadjuvant solution. Some makers of the vaccine use an Aluminum compound as part of the coadjuvant, and here lies the problem.

It seems that some Aluminum compounds are carcinogenic (indeed, most metals that are not biologically inert can cause damage to the organism, with cancer at the end of that list), and molecules containing Aluminum have been found encased in fibrosarcoma cells, which indicates that the healing process mediated by the fibroblasts is deregulated by the Aluminum coadjuvant (they actively try to buffer it). As a result of the immune system deregulation and enhanced fibroblastic activity, the fibroblasts start to multiply out of control and eventually spread out, acting like they are healing a wound but with no real direction. Having this type of tumor not relapsing would be like having a wound that your body would stop trying to heal. Fat chance! With time it just turns into a huge ball (with tendrils...) of scar tissue (fibroblasts deposit new collagen as their main synthetic function), which then dies and rots, making way for ulcers and infections that can't heal because the very cells that were supposed to do so are cancerous (sad irony).

What about the indirect participation humans have in feline fibrosarcoma, you ask? Well, it actually comes out of our good mutual partnership. Do you remember what was the cat's function aboard sailing ships? They were there to get rid of the mice, of course. Do you also remember what is the trademarked illness of the pirates and sailors? That's right: it's scurvy! Scurvy is a disease caused by the chronic lack of vitamin C. It is characterized by bleeding from the gums and other mucous tissues, loss of teeth and open wounds. These appear because without vitamin C, your body cannot synthesize collagen (through your fibroblasts), so, you cannot heal wounds, and any old wounds or places where there is ancient or sparse collagen will open up and fall apart (yep, the body basically discombobulates...). This happens because humans are one of only four (4!) animal species that cannot synthesize vitamin C in their bodies. Cats and dogs are not part of this short list, but that's were we come in to the picture. You see, mice, rats, small omnivores and herbivores in general, produce more vitamin C endogenously than strict carnivores like cats and dogs, even though they weigh a fraction of their mass. Both cats and dogs are well adapted to get all the extra vitamin C from their prey, whilst we depend on supplements in our food. While they were eating our unwanted guests, or our scraps, they were getting their needed quota of vitamin C, but when we swapped that for manufactured food, they lost that important food staple. Now, they won't get scurvy because they still produce some vitamin C, but it is now harder for them to recover from injuries (in terms of collagen deposition).

When a cat develops a fibrosarcoma, the mutated fibroblasts spread by dissolving the extracellular matrix and travel through the spaces between the tissues. It is expectable that if they produced collagen faster, in greater quantity, or with greater quality (sometimes the body cuts corners...) the cancerous fibroblasts would have a harder time spreading, and might even produce so much collagen that they would encase themselves in a collagen prison, turning a malign tumor into a benign one. Quite amazing, no?

The effect of vitamin C supplementation was further demonstrated on what is an apparently unrelated illness. One of the worst diseases that cats can get is the Feline Infectious Peritonitis (FIP), a seemingly incurable, fatal disease. Like the virus induces fibrosarcoma, this one is also caused by a virus, the Feline Infectious Peritonitis Virus, which is in turn a mutation of the Feline Enteric Coronavirus, which is quite common and does not typically cause problems by itself. Now, there are some anecdotal accounts that several cats have been saved through intravenous administration of vitamin C in ascorbate salt form (vitamin C is known as the biologically active form of ascorbic acid), and indeed, a veterinary doctor named Dr. Wendell Belfield has succeeded, back in 1965, to treat a dog suffering from the Canine Distemper Virus, by injecting a dose of 2000 milligrams of sodium ascorbate intravenously to the dog. This current of treatment is described as "Orthomolecular Medicine", this being the expression coined by Nobel award winner Linus Pauling.

There is an important caveat, though. Prolonged and excessive use of vitamin C in cats, tends to predispose them to the formation of oxalate deposits in their kidneys (typically, they form Calcium oxalate stones), which are the hardest type of kidney stones to treat because they are favored by acidic conditions. And it is known that cats are prone to have kidney problems, so this will probably affect them in the long run. Ah, nothing like a balanced diet and healthy lifestyle, and that's were we can make a difference.

I don't really like miracle cures, but if they can be repeated, they stop being miracles and become science!

If you can understand what's going on, you can think of a way to control it. Just remember, there is no problem that cannot be solved (by default, anyway).

Here are some more links:

Fibrosarcoma with Typical Features of Postinjection Sarcoma at Site of Microchip Implant in a Dog

Fibrosarcomas: Cancerous Tumors in Cats and Dogs

Update on Feline Fibrosarcoma

Vaccine-associated feline sarcomas

Feline Post-Vaccinal Sarcoma - A Literature Review

Feline Vaccine-associated Fibrosarcoma: An Ultrastructural Study of 20 Tumors (1996–1999)

Fibrosarcoma - Felipédia

Feline fibrosarcomas at vaccination sites and non-vaccination sites - needs subscription

Fibrosarcoma arising at the site of a retained surgical sponge in a cat - needs subscription