A Molecular “Switch” in Breast Cancer Cells Signals Metastasis

Metastasis, the spread of cancer from its original location in the body, makes cancers harder to control and treat.

Now, a new study has discovered a metastasis-related molecular “switch” inside breast cancer cells. In one case, the cell stays put and divides more rapidly, enlarging the primary tumor. If the switch flips, the cell starts to divide more slowly while its potential for metastasis increases.

“This could be a marker to determine whether or not the breast cancer is likely to metastasize or not,” said Professor Susan Rotenberg of Queens College and The Graduate Center, CUNY. Rotenberg is an author on the study, which appears in Cellular Signalling.

Cells contain structures called microtubules, which are involved in cell movement and proliferation. One of the building blocks of a microtubule is a protein called alpha-tubulin. There is a specific site on each alpha-tubulin, called serine-165, that is involved in this toggle switch. If the site is phosphorylated — in other words, if an enzyme adds a small molecule containing a phosphorus atom to the site — the breast cancer cell becomes more likely to metastasize. If not, the cell will proliferate more quickly.

For a cancer patient, the latter option is more favorable. If the cancer stays in one part of the body, it is less complicated for doctors to treat.

Because some cancer cells have a mutation that blocks this phosphorylation, genomic testing could potentially determine what a patient’s cells are more likely to do. However, Rotenberg said, more research is needed to confirm whether the mutations are common enough to be clinically useful.

The study also gives researchers a better understanding of signaling pathways in breast cells. “There is a lot to learn here about the basic science,” Rotenberg said.