Download TUMOUR CELLS PROLIFERATE BY KILLING SURROUNDING

TUMOUR CELLS PROLIFERATE BY KILLING SURROUNDING NORMAL
CELLS.
Madrid, January 14th 2008. Eduardo Moreno, Head of the Cellular Competition Group
at the Spanish National Cancer Research Centre (CNIO) in Madrid (Spain) published
today a review article in the magazine Nature Reviews Cancer (Moreno, E. Nat. Rev.
Cancer, AOP, January 2008) describing a novel hypothesis regarding the early detection
and treatment of cancer. Tumoural cells can grow silently, by killing and eliminating normal
surrounding cells in a way that morphological malformations are not detectable. The
molecular description of such a phenomenon could help to develop novel therapies aimed
at the early treatment and detection of several cancers.
Early stages of cancer formation.
It is a widespread consensus that the vast majority of human tumours are monoclonal
growths descended from single progenitor cells that — through several rounds of
mutations and selection — overcome the constraints imposed by multicellularity and
development. However, as most human tumours are quite advanced when detected,
comprising a billion or more cells at the time of discovery, medium and late stages of
tumour development are better understood than initial events, especially those that may
occur before morphological alterations are clinically detectable. Therefore, those early
stages, although predicted by the monoclonal theory of cancer, are largely a mystery.
However, these initial events are probably vital for tumour progression, and
understanding and detecting these early stages might help to successfully treat cancer.
One reason why a pre-tumoural lesion may not be detectable is because it is too small to
be noticed, for example, when the number of tumoural cells present in the tissue is in the
order of hundreds or thousands
of cells.
A new type of cancer therapy based on cell super-competition.
Recent research in the fly Drosophila melanogaster suggests that reduced cell numbers
might not be the only reason why a group of proliferating cells may grow unnoticed. What
if a transformed cell could proliferate without producing morphological malformations,
because the increase in cell number was balanced by the apoptotic elimination of
surrounding cells and, therefore, the total cell number did not change? An intriguing
phenomenon in D. melanogaster known as ‘cell super-competition’ has been described to
do just this: cells proliferate by killing surrounding wild-type cells by apoptosis so that the
total cell number does not change. As a consequence, clonal expansion did not generate
morphological aberrations and the growth of these cells passed unnoticed. What is cell
competition, what do we know about it and how might it relate to cancer? In the
perspective published by Eduardo Moreno in Nature Reviews Cancer a hypothesis is
proposed that identifying “cell competition response genes” could be a novel approach to
cancer treatment and detection, even before morphological malformations are detectable.