A breast milk protein that sustains life could become an important target for scientists working on anti-cancer drugs.

Research into how breast milk is produced could help in the search for a breast cancer cure.

Melbourne scientists have discovered the protein MCL-1 is vital for keeping milk-producing cells alive and sustaining milk production in the breast.

Without milk, mammals cannot survive, making MCL-1 essential to their survival.

"The bottom line is that this is a really important survival protein in breast tissue," said Geoff Lindeman from the Walter and Eliza Hall Institute.

"We've discovered that it's essentially the key protein that helps keep breast tissue alive during lactation."

Professor Lindeman said the research team found a growth factor known as EGF triggers the production of the MCL-1 protein.

"EGF and MCL-1 have been implicated in helping breast cancers grow.

"In the longer term, this work raises the question as to whether or not MCL-1 could be an important target for developing anti-cancer drugs."

The research team has spent the past 15 years investigating breast development in a bid to ultimately find a breast cancer treatment.