does all people have cancer cells in their body?

i think we all have cancer cells in our body and it will have if we will not eat healthy food such as vegetables and fruits,they said that cancer cells will grow if we always eat meats and those canned foods that full of preservatives.

Not exactly,i think what you meant is proto-oncogenes,which exist in the cells under normal condition,they play an important role in the growth and differentiation of cells.but due to abnormally increased expression,mutations or translocation,they may help to turn the a normal cell into a cancer cell which aslo be called tumor cell,this is the basic process of tumor generation.

I have heard of this one too, I don't really know if it's true. I was told that cells turn into cancer cells all the time but most of they switch again and go away, it's only sometimes when they don't do. I'm not sure if that's true, but appreciate you rising the question, would like to know more!