The switch that might tame the most aggressive of breast cancers

Australian researchers have found that so-called 'triple-negative breast cancers'1 are two distinct diseases that likely originate from different cell types. This helps explain why survival prospects for women with the diagnosis tend to be either very good or very bad.

The Sydney-based research team has found a gene that drives the aggressive disease, and hopes to find a way to 'switch it off'.

The aggressive form of triple-negative breast cancer appears to arise from stem cells, while the more benign form appears to arise from specialised cells.

Stem cells have many of the same features as cancers. They are plastic and flexible, and have the ability to proliferate and spread into other tissues - deadly traits in cancers.

Previous studies have shown that breast stem cells are needed for breast growth and development during puberty and pregnancy, although how they evolve from stem cells into specialist cells has been unclear.

The new study has shown that a gene known as 'inhibitor of differentiation 4' (ID4) determines whether a stem cell remains a stem cell, or whether it differentiates into a specialist cell.

Scientists find new target for most aggressive breast cancer

A new study has linked deficiency in a gene that controls autophagy - a process that recycles cell waste - with triple-negative breast cancer. The researchers suggest increasing activity of the gene could be an effective way to treat patients with this most aggressive and stubborn cancer.

Chemotherapy has limited effect against triple-negative breast cancer.

Reporting in the journal EBioMedicine, the University of Texas (UT) Southwestern Medical Center team describes how it found a strong link between the autophagy gene beclin 1 and the most aggressive type of breast cancer.

Beth Levine, a UT professor and director of the Center for Autophagy Research, and colleagues analyzed data from over 3,000 patients in two large breast cancer databases: the Cancer Genome Atlas (TCGA) and the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC).

They found that reduced activity of beclin 1 was linked to both a higher rate of triple-negative breast cancer and a poorer prognosis for breast cancer patients.

The team believes this is the first study to report a link between beclin 1 and triple-negative breast cancer in humans, and confirms similar findings from mouse studies.

Prof. Levine, who is also a Howard Hughes Medical Institute investigator at UT Southwestern, says their findings suggest decreased beclin 1 activity contributes to breast cancer and poor survival outcomes:

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