Cancer: A Matter of Cellular Programming
Maher, Brendan A. (2004) The Makings of a Microarray Prognosis. The Scientist, March 15, pp. 32-36.
“Countless things can go wrong in the complicated cell division process. Checkpoints fail, genomic instability increases, and when anarchy reigns, cancers spread. In trying to assess what is doing the damage and predict the damage yet to be done, doctors have an admittedly blunt set of tools to porfile renegade cells. Histopathology andgeneral prognostic indicators such as health, age, and metastatic spread do little to account for the breadth of tumor variety even within fairly specialized tumor types.
“Snce researchers first stated toying with microarrays, they have considered the molecular pofiling of tumors to be an important potential use. The genes that switch on and off may reveal a cancer’s biology and future, and, some hope, its responses to a variety of treatments.”
Metastatic models of cancer are changing due to analysis of gene behavior in tumors. The ability of a tumor to spread to other organ systems was previously considered a phenomenon that occurred late in the tumor life cycle. It now appears that certain tumors are prone to metastasis from the beginning and that they have subpopulations of cells with affinity to certain organ systems.
The implications of this is that treatment should be different for cells prone to metastasis and those with less aggressive tumors should not be exposed to unnecessary chemotherapy.
For example, a recent study looked at 20 year old tissue samples from breast cancer patients without lymph node metastasis. At that time they were not treated with chemotherapy. Out of 98 women younger than 55, there were 34 with a recurrence. Today, in the U.S., 95% of these patients would be treated with chemotherapy. This means that 65% of these patients would not need chemotherapy, but would get it anyway leading to excess costs and morbidity.
So it looks like patients should demand the health care system do a more detailed examination of their tumor before they rush to chemotherapy. It could not only save them severe debilitating effects, it could reduce healthcare costs.