Cancer is in almost all cases a problem of improper gene expression.
Cancer is in almost all cases a problem of improper gene expression.-me-
Cancer can be caused by various factors which affect gene expression. The wrong replication of a cell can cause a deffect in the DNA which controls gene expression, that is why cancer is most common in older people. Also some viruses can affect the DNA which controls cell replication and thus cause cancer. The mechanism which controls cell replication is quite involved and thus can fail at many points. It is a wonder that it works as well as it does for as long as it does.