Why aren't we warning the public about the risks of blood contact of cancer patients? If it's actually true that secondary tumors are caused by those rogue cancer cells that are hitchhiking through the blood stream, or lymph system, then why do cancer cells of the primary tumor hardly ever travel to adjacent tissues?
metastases is not a theory, it's a fact.
Are you saying from one person to another?
Cancer is not well understood in many ways. Many cancers metastasize to specific tissue types (breast cancer usually metastasizes to the lungs, liver,and bones while colon cancer usually invades the peritoneum, liver, and lungs). It would appear the most common sites of metastasis involve the liver, lungs,and bones for most types of cancer.
According to http://www.cancer.gov/cancertopics/fact … etastatic,
"The ability of a cancer cell to metastasize successfully depends on its individual properties; the properties of the noncancerous cells, including immune system cells, present at the original location; and the properties of the cells it encounters in the lymphatic system or the bloodstream and at the final destination in another part of the body. Not all cancer cells, by themselves, have the ability to metastasize. In addition, the noncancerous cells at the original location may be able to block cancer cell metastasis. Furthermore, successfully reaching another location in the body does not guarantee that a metastatic tumor will form. Metastatic cancer cells can lie dormant (not grow) at a distant site for many years before they begin to grow again, if at all. "
But that still doesn't explain it. If the theory is true, about the rogue cells, then any blood-on-blood action could cause cancer. It would also mean that blood is the key and if that were true, then the brain would have filtered it out from the other parts of the body. So why wouldn't the brain perform it's functions? They have tested the filter, it was unharmed and in perfect order, yet the cancer spreads from the brain to other places... why? The immune system, and other cells and the possibility for growth would make the chances of the cancer growing slim. Even slimmer as the cells travel through the body... so why are the cells not attacking the closest place? It is all ready weakened and perfect breeding ground for more growth. That is proven by the tumors growth across the brain.
I think there is a lot that we DON'T know about cancer. There are studies showing impairment of the blood-brain barrier with cancer patients, however - the barrier is compromised with metastases to the brain (see this study on breast cancer patients: http://www.hindawi.com/journals/pri/2011/920509/)
From the aforementioned article, it would appear that the genes specific to the tumor cell determine which tissue it will grow in:
"Searches for genetic determinants of metastasis have led to identification of gene signatures that selectively mediate breast cancer cell metastasis to bones, the lungs, and the brain [13–15]. Based on previous work on genomic analysis of breast cancer metastasis to bone and lung, the Massagué group identified three tumor metastasis genes that mediate extravasation through the BBB and cancer cell colonization in the brain"
I agree with you. Some of my countrymen even consider cancer as a curse. We should help n spreading cancer awareness. I know it can't be treated but at least we can apply some methods towards prevention.
Awareness and continuing research. Some forms of cancer have been conquered - Gleevec, for example, is a relatively new drug that cures Chronic Myeloid Leukemia. Molecular therapy (like Gleevec) is a much better way to attack cancer, because there are few side effects and the drug is extremely effective (you can read about this specific drug here: http://www.cancer.gov/newscenter/qa/2001/gleevecqa.
Some forms of cancer are still incredibly deadly, unfortunately.
I don't think metastais is a "theory", it is an observed phenomenon that *some* cancers, ast a *certain levels of severity* spread throughout the body--often resulting in a very severe or terminal condition. In these cases tumors will arise in non-adjacent positions.
This by no means implies that cancer it is transmissible via blood. That would require a lot of other factors than just malignant cells in the blood or lymph.
If I had to take a guess, from a scientist's perspective (and keep in mind this is NOT my primary field of study) - it's most likely because cells from another person are not compatible and would recognized as "foreign" and therefore be destroyed by your immune system.
Similar of to organ donations. Organ donors have to be pretty compatible for the recipient not to reject and destroy the donor's organ.
Viruses and bacteria, on the other hand, are not human cells are totally different. Many have mutated to avoid being destroyed by the host's immune system.
I gather from the discussions already posted that cancer is considered as falling under the germ theory of disease. That is, cancer is caused by a germ like virus that would make it communicable. To my knowledge cancer is not caused by germs but by free radicals. For example, superoxide which is a by-product of metabolism of glucose. It consists of two atoms of oxygen with one unpaired electron which, to stabilize itself it grabs another electron of a nearly molecule that belongs to a tissue. This grabbing results in injury that triggers mutation in DNA or cell membrane that graduate into tumor or cancer. Tumor or cancer starts with one cell only whose growth is uncontrolled. Tumor cells that breach the matrix that confines it, usually the bottom, escapes to the blood or to the lymph fluid than invades cells. That's when it becomes metastatic. Bromelain or protease usually dissolves cell matrix, which is also found in papaya and pineapple. Melanoma, skin cancer, can colonize brain cells of the same person not of another person. It is not communicable that is why conventional medicine calls cancer a non-communicable disease. Superoxide is neutralized by superoxide dismutase, an enzyme, that converts it to hydrogen peroxide which is a reactive oxygen species that acts like a free radical in that it grabs another electron that results in injury. Hydrogen peroxide is dismantled by glutathione peroxidase into safe water.
Interesting... I really appreciate your post. If cancer does not communicate like other diseases, then would it be logical to create a medicine that does to battle it? Perhaps one that would "light" up the cancer cells that would show the original rogue cell.
I think you are mistaking transferring to other person with transferring in ones on body. When you try to transfer from one human to another, the new host will see the cells as foreign to oneself and destroy it by immune mechanism. While in ones own body the cancer cells are usually similar to the normal cells and hence not 'seen' by immune cells. The cancer cells only at times carry proteins that are entirely different and usually the proteins are similar to other normal proteins, hence cannot differentiate between normal and abnormal.
There are a couple of known cases where a virus can eventually lead to cancer. The human papillomavirus is one example. A woman infected has a higher risk of cervical cancer - it doesn't necessarily mean she'll get it. But most cervical cancers are caused by HPV infections. And HPV is an sexually transmitted disease. It's important to note that it's the virus that can spread from human to human, it's not cancer cells spreading between humans as this original forum question seems to be asking.
It is more likely virus does not transmit cancer. Macrophages, components of the immune system, mediated by the inducible nitric oxide synthase, produces nitric oxide and use it as bullets to shoot virus and inflamed cells. NO causes mutation in stricken cells including healthy cells in the vicinity. Mutation results in tumor or cancer. Macrophage uses a free radical, as bullet (Cranton, E. and A. Brecher. Bypassing Bypass. 1984). So, the free radical causes cancer.
That is correct. Viruses cannot transmit "cancer" in the sense that a communicable disease is transmitted but the presence of the virus and what the virus eventally does within the host that causes the eventual onset of cancer by damaging DNA via free radicals.
Countering tumor or cancer takes a different tack. A free radical like nitric oxide (NO) inflicts disease differently from that how a virus does. Nitric oxide is a product of reactions (on L-arginine) catalyzed by three enzymes: endothelium nitric oxide synthase(eNOS) produces one; neuron nitric oxide (nNOS) produces another; inducible nitric oxide synthase (iNOS) produces still another. Each has specific functions. NO of eNOS is a messenger that signals the endothelium to dilate and allow the flow of more blood (the same as done by nitroglycerin given during an episode of angina pectoris). NO from eNOS is beneficial. NO mediated by the macrophage, a component of the immune system, is used by the macrophage to shoot virus (Cranton, E. MD and A. Brecher. Bypassing Bypass. 1984). It kills the virus or bacteria and also strikes healthy cells in their vicinity inflicting damage to their membranes or DNA. That can result in inflammation or mutation or scar or stenosis as happens in the initiation of rheumatic heart (triggered by the bacteria Streptococcus pyogenes). So, a free radical could serve as a messenger and as a grabber of electrons. Inflammation is evidence of damage done by free radicals. NO produced by iNOS is countered by antioxidants to mitigate the preponderance of free radicals. A free radical has a charge that can be neutralized by a charge from the electron of hydrogen atom that comes from antioxidants. That's how an antioxidant does battle against a free radical. The rogue in cancer is a free radical. Now we cannot escape from free radicals. It is a matter of balance between free radicals and antioxidants. Our body has built-in antioxidants like superoxide dismutase, glutathione peroxidase, and catalase. These can be supplemented by vitamin B complex, A, C, D and coenzyme coQ10. Infusion chelation therapy also counters free radicals. EDTA (ethylene diamine tetra acetate) has a negative charge that can neutralize free radicals, and remove and bind with minerals like iron and copper in whose presence during a reaction produce hydroxyl radical and alkoxy radical. NO produced by eNOS can also be caught by antioxidants that is why angina occurs; or NO is not produced because an artery injured and with a plaque does not produce NO which is released by the inner wall of a normal artery.
The best approach against tumor and cancer is prevention that can be done with antioxidants. Cancer is also amenable to treatment during early stages (likely to be effective in stages I and II).
Heritable colon cancer can be prevented, and halted. The gene involved is adenomatosus polyposis colitis (APC). The first mutation happens during meiosis. The next mutations occur in the mitotic cells of the sibling. One who inherited APC has thousands of polyps in the intestine. But 5 to 7 mutations more must occur in one mitotic cell before a full-blown colon cancer develops. Counters before each mutation can be mounted. The last mutation is the mutation of both alleles of p53 gene that serves as a switch in mitosis. Once both alleles had been mutated, development of colon cancer cannot be stopped. p53 blocks the mitosis (uncontrolled growth) of the one cell that had sustained the 5 mutations in genes k-ras, DCA, etc). Colonoscopy can catch a mutating polyp early on that is still in the adenoma stage. A polyp that sustains a mutation in k-ras gene turns into adenoma, a name applied to stages up until p53 genes had been mutated when colon cancer now arises. Immunotherapy works against cancer; it kills cancer cells only. Chemotherapy produces a lot of free radicals that destroy both cancer cells and healthy cells in the vicinity that is why it could create another disease. It destroys the bone marrow that is why bone marrow transplant is part of a protocol involving adriamycin. Before administration, part of the bone marrow is taken, preserved and transplanted back to the same patient once chemotherapy sessions had been completed.
I will edit my recent post: for APC I meant adenomatosis polyposis coli. Adenoma is "an intermediate tumor with fingerlike projections." The mutations that develop into colon cancer are: APC (one alelle mutated), k-ras proto-oncogene (one allele mutated); gene DCC (two alleles mutated); gene DC4 (two alleles mutated); gene DPCA (two alleles mutated; and V18-1 (two alleles mutated.
Where did you get your information? I've been looking through medical books for a while and none of them have been that specific.
I read this thread with great interest and I'm grateful for the info here. Just recently it seems that my everyone I know has cancer or has a family member of friend that has.
At least this thread has given me a little comfort.
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