Tracking tumours
AGONISING biopsies to detect cancer, which bring as much trauma as the following invasive surgery, might become a nightmare of the past if a technology developed by us-based Matritech Inc receives the approval of the Food and Drug Administration (FDA).
The technology works on the basis of at least one of the origin-of-the-disease beliefs surrounding cancer: some researchers believe that a cell's internal architecture is defined by what they call nuclear matrix proteins (NMPS) and other similar proteins. These proteins not only play a supporting role for the DNA, which carries genetic code, to do its work, they also help to control gene functions.
NMPS were targeted by Matritech's researchers to develop their cancer detection tests. The background is that some NMPS show up in tumour cells and not in normal cells: if these telltale proteins were to be detected in blood and urine samples, then this method would turn out to be a highly accurate cancer diagnostic test, claim researchers.
Matritech has already approached the FDA for the approval of its urine test for bladder cancer. The company is developing blood tests based on NMPS to catch cancer of the colon, prostate, breast and cervix.
Some biologists are sceptical, even while they acknowledge the validity of the research. Their doubts are directed at the importance Of NMPS in cell functioning. Says Phillip Sharp, biologist at the Massachusetts Institute of Technology, "I think it's going to be more powerful to look at" genes associated with cancer to understand turnours.
Last year, Matritech's scientists identified 6 different NMPS from 18 colon tumour samples which were not evident in tissue samples from normal colons. Similarly, in 1993, scientists at the Johns Hopkins University reported having found one NMP from 14 prostate tumour cells. Dubbed Pc-1, this NMP was not detected in 13 normal prostate tissue samples taken from men who had non-cancerous prostate enlargement.
Scientists are not sure why certain NMPS appear when cancer begins its death run, but Donald Ingber from the Harvard Medical School, offers a theory. According to him, the NMps are ,ng cancer cells chained to the DNA 3se NMPs into bloodstream molecule in such a way so that only certain genes are activated. This normal tethering pattern is maintained by mechanical pressures. In cancer, this NMP chain gets mangled and does not react normally to the pressure, thus allowing wrong genes to be switched on, resulting in runaway cell growth.
But Sharp and others question this theory, wondering whether NMP abnormalities are the root cause of cancer or the result of basic changes in gene structure that lead to cancer.
Whether NMps are the cause or the effect of cancer, Matritech's researchers, along with other enthusiastic and optimistic scientists from Johns Hopkins University and the Harvard Medical School, are keeping their hopes high as they await FDA approval of their bladder cancer detection test.