Researchers advance theory on cancer spread

In collaboration with the Press Association

Researchers from the University of Basel have uncovered new details about the way cancers spread around the body.

Their research has found the underlying molecular basis for the three separate types of cancer spread, and shown that each is caused by a different biological pathway.

Because these processes all involve different biological molecules, scientists might be able to block them by designing new drugs.

In the first pathway, a single cell breaks off to form a new cancer.

Professor Gerhard Christofori, head of the Tumour Biology group at the University of Basel's Centre of Biomedicine, explained: "When single cells detach from the 'mother tissue', we can observe the inhibition of a protein called E-cadherin."

Because this protein's function is blocked, a cascade of events leads to a single cell breaking loose.

In the second pathway, a clump of cells detaches itself from the tumour. This involves a protein called podoplanin.

"We were able to show that podoplanin induces the formation of so-called filopoda, long protrusions stemming from the front line of the tumour that sense the environment and help the cells to make decisions as (to) where to go," Professor Christofori revealed.

The third mechanism involves the formation of new lymph vessels, and occurs when a tumour secretes proteins that cause nearby vessels to 'replumb' themselves to feed it.

Break-away cancer cells can then travel down these new blood vessels to more-distant parts of the body.

This pathway appears to involve two 'growth factors', VEGF-C and VEGF-D, which can cause new lymphatic vessels to develop, enabling tumour cells to spread through the lymphatic system and leading to the development of new tumours in a person's lymph nodes.

Ugo Cavallaro, a scientist at IFOM - The FIRC Institute for Molecular Oncology of the Italian Foundation for Cancer Research pointed out that the three processes were not mutually exclusive in an individual.

"These results altogether could change the way scientists have so far thought about [cancer spread]," he added.