from what i've read in the net so far,

a tumor is dangerous when it is malignant or can spread to other parts..

take for example breast cancer..

ok, firstly the cancer cell from the breast detach, then attach itself to another part like the brain or colon (example, not a pro here), then proliferate into another tumor..

the tumor will then block the normal function of the non-cancerous cells. thus causing death?

what else happens??? how does an undetected cancer kill a person???

thanks in advance..

Breast cancer, like other cancers, is the result of mutations to genes. Mutations in tumor suppressor genes or oncogenes are the big guys that cause a majority of the damage.
Tumour suppressor genes are the body’s breaks, they slow down the cells growth if it’s growing too fast. Oncogenes are growth genes…think accelerator , when these genes are expressed the cell grows and divides, grows and divides….
In BC, the genes implicated with it are DNA repair genes, ie XRCC1, oncogenes, iw LMYC, Transcription factors, BRCA1, Growth factors, TGFB1, Cell cycle, BRCA2, hormone receptors, tumour suppressors, drug resistance, internal signaling, cell surface proteins, external signaling, cell to cell adhesion, etc etc ect.

When the body’s cells become mutated to a certain degree, they form a tumor, they may be malignant, spread…. Or benign, not spreading. Normal body cells divide in a controlled (read “slow”) rate, but malignant cells duplicate in an uncontrolled rate, and they’re oh so quick. If you’re stuck down with a malignant tumour, the cells can migrate to other parts of the body, where secondary tumours form, aka metastasis.
Haematological cancer is a cancer of the blood. Solid tumours…well they’re solid. Sacroma is a cancer from bone, muscle, connective tissue. Carcinoma is cancer from an epithelial cell, ie the glands and outer layer of skin that lines the blood vessels, hollow organs, body orifices.
So, while the primary cancer are often able to be treated by surgery, it’s the metastasis that kill you. Cancer cells have no function in the body. If enough healthy cells are replaced by cancer cells, the affected organ can no longer work.
Generally speaking, if a cancer spreads to take over a part of the body that performs an essential function, this can kill you…. Ie digestion = blockage. If it effects the lungs, there is too little effective tissue to allow oxygen to be absorbed into the body to sustain life. Or, it can cause a block that’ll lead to collapse followed by infection. These people often don’t have the greatest immune system, and can’t fight off the infection, even with the help of antibiotics. Bones and liver, that’ upsets the chemical balance of the body. Our body operates within a very fine limit, and well, think of it as the princess and the pea, “ ooooh can’t work today, this isn’t right”. Normally, there are mechanisms that can seek out this imbalance, but when the balance is too far out…well it just gives up. So if, for instance, there is too much calcium in the body, and body says “stuff it, I quit”…well the calcium levels will continue to rise and rise, until the patient becomes unconscious, and dies.
If the cancers have already enetered the blood stream, they can affect the entire body. So, if you remove a tumour from one site, it’s only a matter of time before it turns up somewhere else. They can lay in wait as well. So just when you least suspect it, you’re struck down again. Imbalance, organ failure, and infection. Chemotherapy and Radiotherapy can also cause cancer, that’s why they’re not tested on normal healthy people like other drugs. Ethical reasons. So, the idea is that they’ll kill more of the quickly dividing cancer cells and less of the slow normal healthy cells….but at the same time giving mutations in these healthy cells that’ll over time develop into cancer cells, that’ll divide and cause cancer. Cancer that’ll spread and cause imbalance, or organ failure, or infection, or a combination of the three.

Does this help?

yes! thanks for taking the time to reply!..

surely the body is a system that attempts to maintain a constant internal environment and keeping everything balanced?

Homeostasis is one of the fundamental characteristics of living things. It is the maintenance of the internal environment within tolerable limits. Human beings are regulators. Regulators try to maintain the parameter at a constant level, regardless of what is happening in its environment, ie, maintaining a constant body temperature.

All sorts of factors affect the suitability of our body fluids to sustain life; these include properties like temperature, salinity, and acidity, and the concentrations of nutrients such as glucose, various ions, oxygen, and wastes, such as carbon dioxide and urea. Since these properties affect the chemical reactions that keep bodies alive, there are built-in physiological mechanisms to maintain them at desirable levels.

However, it should be noted that homeostasis is not the reason for these ongoing unconscious adjustments. Homeostasis should be thought of as a general characterization of many normal processes in concert, not their proximal cause per se. Moreover, there are numerous biological phenomena which do not conform to this model, such as anabolism. But, ignore that for the time being…

Anyway, back to regulation… when it’s cold, out muscles shiver to produce heat. Also, there is the decomposition of fat, aka non-shivering thermogenesis. When it’s hot, we sweat. Simple.

Chemical regulation is more complex, involving various pathways and systems. But, basic examples are, the pancreas produces insulin and glucagon to control blood-sugar concentration. The lungs take in oxygen and give off carbon dioxide. The kidneys remove urea, and adjust the concentrations of water and a wide variety of ions.

Most of these organs are controlled by hormones secreted from the pituitary gland, which in turn is directed by the hypothalamus.

A normal (non-cancerous) person is able to use these mechanisms of control. Ie, a normal person had too much salt on their chips… the body clears the sodium out, no problem. A normal person has too much salt on their chips every night for 15 years… they have high blood pressure, cholesterol problems, water retention, bad kidneys… years of abuse.
Also applies with calories (!) If a normal, healthy person, takes in too many calories, the body will simply eliminate them… not turn it into fat. It’s only when there is a constant influx of calories that the body decides to pile on the kilos .

When the same mechanism is constantly being used, it can become overwhelmed, and shuts down… for instance, diabetes in the obese. It’s similar with cancer patients. So, when a patient with metastasis has an ion imbalance, ie calcium, the body will sort it out…again, and again, and again... and after a while, the mechanism that controls calcium will stop working.
You also have to take into account that in a non-cancerous patient with an ion imbalance which is no longer regulated because of years of abuse through bad diet and lack of exercise etc, a cancer patient may also have the ion imbalance that is no longer regulated because of the cancers inhibiting the process, or the organ that usually controls it is no longer working, or the genes that are required for the production of the specific proteins needed are mutated…etc etc etc.

The body does try to keep everything balanced… but sometimes the system is so out of whack that it can no longer cope with the strain that is placed on it.

spelling is my friend