Proceedings of the National Academy of Sciences (PNAS) has published the study online this week.

Argentinian scientist Andrés Dekanty, a Juan de la Cierva researcher in the Milán lab and first author of the article, explains that "for the first time we have a genetic model that allows us to understand the events that take place, starting from when cells begin to accumulate genomic errors until the development of a tumour." The Milán team began by provoking genomic instability in a selection of cells in the fly wing. They then prevented these cells, with an aberrant number of chromosomes (aneuploidy), from succumbing to the cells' natural defense mechanisms so that they would survive. From there, they observed that the cells spread throughout the tissue, became mobile, activated the growth of adjacent cells, and degraded the basal membrane that kept them in place, allowing them to break free and even invade nearby tissues. "All of these events are things that we see in cancer. This fly model will therefore help us to identify each of the genes and molecules involved in epithelial cell detachment (delamination), motility, abnormal growth, basal cell degradation and invasion," says Milán.

"This study takes things one step beyond, however," say the researchers, "and opens a fundamental conceptual debate." This is the first time that these phenomena have been described in relation to genomic instability. "This has allowed us to propose something that hasn't yet been possible to study in depth and that now should be taken into serious consideration. Is genomic instability the cause of tumorigenesis?" says Milán.

Genomic instability, a cause of cancer?

Cells in all human cancers display considerable genomic instability. Their genomes are full of mistakes. "If we can demonstrate this direct correlation, we will have something very specific to work with to find precise targets. Aneuploid cells don't exist in healthy organisms. If we can identify what differentiates a cell with genomic instability from a normal cell, we may be able to identify specific treatments," says Dekanty.

Today, cancer therapies are aimed at slowing proliferation, or cell division. A major problem with this is that all cells -- both cancerous and healthy ones -- divide. Treatments are therefore associated with many side effects. "There isn't a treatment available that attacks only the cells with genomic instability," say the researchers. "If we can clearly differentiate one from the other, we'll hopefully be able to find drugs that target them specifically," explains Dekanty.