For many decades, researchers were trying to uncover the role of normal tissues in the formation of a cancer or a tumor. Although many researchers believed that normal tissues initiate the formation of cancer cells, they fail to come up with an acceptable explanation. However, in recent times, researchers have uncovered a contradictory viewpoint in which they demonstrated how normal tissues suppress cancer cell formation both in mouse models as well as in humans.
One of the studies carried out by a team of scientists from the Center for Cancer Research’s Mammary Biology and Tumorigenesis Laboratory concluded that normal cells were able to exert a temporary inhibitory effect in relation to the potential of a cancer forming cell in mouse models. Thus, it was possible for normal tissues to inhibit the cancer cell formation although the cancer forming ability of such cells were never lost.
In order to arrive at these conclusions, the researchers implanted mammary epithelial cells from a mammary gland of an erbB2 overexpressing mouse model, into a mammary fat pad of a mouse model, which does not demonstrate erbB2 overexpression. The erbB2 overexpression gene functions in a similar way to the HER2 gene, which contributes to aggressive breast cancer in women. Following the transplant, the erbB2 overexpressed cells rapidly formed a tumor. However, when the implanted cells were a mix of normal mammary epithelial cells and erbB2 overexpresse cells, there was no evidence of a cancer cell formation. However, when the same erbB2 overexpressed cells were re-extracted and re-implanted in a different mouse model, they again gave rise to a cancerous tumor. Thus, researchers were able to conclude that the normal cells inhibited the erbB2 overexpressed cells through a active mechanism and prevented the formation of cancer cells.
Meanwhile, according to an article published in the Journal of Biological Chemistry, a form of RNA secreted by normal cells has been shown to inhibit the proliferation of potential cancer cells. The name given for this type of RNA is ‘exosomal tumor suppressive micro-RNA’ and it tends to act as an inhibitory signal to a potential cancer. However, these miRNAs should be released nearby to potentially cancerous cells and there should be a cell competitive process to see such inhibitory actions taking place over most types of cancers.
Looking at this evidence and many other researches currently in progress, it is apparent that normal cells do have a vital role in suppressing a potential cancer. Therefore, future research in this area should look towards making use of this window of opportunity in order to experiment with the potential use of this process to prevent cancers or perhaps even treat them.