Re: How does tumours develop?

This is great question, but a complicated one!

Tumors are a group of cells that have lost their normal function in the body 
and divide uncontrollably. These cells come from a normal cell that has been 
mutated.  There are many different mutations in genes that could lead to 
cancerous cells and tumor formation.  Genes that code for proteins that are 
required to inhibit cell division (mitosis) and genes that code for protein 
involved in making sure that mutations do not accumulate in a cell are 
common sources of cancer.  Once a cell has become mutated in these major 
control mechanisms, it may grow uncontrollably and produce a tumor.
Tumors can be either benign or malignant.  Benign tumors will grow but not 
spread to other areas of the body. All tumors are harmful to the body 
because they are made of cells that are not functioning to help the body any 
more and they are taking up food and space.  Tumors continue to grow, and 
can also divert blood vessels to feed the tumor with nutrients 
(simultaneously depleting the surounding tissue of essential nutrients in 
blood).  Space is very important, and as a tumor grows, it can damage 
surrounding tissue as well.
Cancer is a very complicated and fascinating feild.  There are many 
questions in the Mad Scientist Archives that have been answeared that 
may help you understand how a tumor develps from a single cell, grows and 
spreads through the body.
Good luck!
Elena Rodriguez
Graduate Student, University of California, Berkeley