CanThera Cancer Therapy Center
1314 East Sonterra Blvd
Suite 5101
San Antonio, TX 78258
Phone: (210) 404-0044
FAX:    (210) 404-0045

What is Cancer?

Introduction

We are made of millions and millions of cells which work tirelessly to maintain all the necessary body functions. Different hormones, growth factors and cytokines pass information between cell groups to coordinate their efforts and to stimulate or stop production of new cells when necessary.

Cancer cells develop mechanisms to escape these “body laws.” Their only priority is to keep growing. They produce growth factors for themselves, use normal growth factors and hormones, or learn to survive without them. As tumors grow, cancer cells change and adapt, learn new “survival” tricks and conquer new territories by pushing aside or killing normal cells.

What is the cause of cancer?

The “antisocial behavior” of cancer cells is due to damage to their genetic material, DNA. In general, this injury could be due to radiation, chemical substances called carcinogens, viruses. Some people inherit damaged genes from their parents. We might never know for sure what caused your cancer. DNA damage happens throughout out life, but resulting cells are either too abnormal to survive, or get caught by body defense mechanisms before they cause trouble. When body defenses get tricked or overwhelmed, a single escaped cell can start multiplying and eventually becomes a tumor.

Cancer cells have their weaknesses

The aggressiveness of cancer cells comes at a price: the more cancer cells change and grow, the more genetic abnormalities they accumulate and the less stable they become. They can not stop dividing to repair damage to their genes, like normal cells do. They are not very efficient in utilizing energy and have to grab more nutrients. They “get addicted” to a limited set of growth factors and die without them. In other words, although these cells are still “our cells”, they do differ from normal cells. These differences are the basis for systemic cancer therapy.

Are all cancers alike?

Although uncontrolled growth is common to all tumors, not all cancers are the same. Cancers arising from different organs and tissues retain some characteristics of their former selves. They often depend on different growth factors or hormones for multiplication, have different patterns of spreading and respond differently to anti-cancer agents (please see Types of Cancer for links to more detailed information).

Even cancers which arose in the same organ differ from each other because their normal “parent cells” had different functions and/or because they accumulated different types of damage to their genes. For example, some breast cancers have hormone receptors and might respond to hormonal agents, while other breast cancers have no such receptors; some colon cancers have mutations in a gene called Ras and are unlikely to respond to antibody Erbitux, while other colon cancers have normal Ras gene.