Scientists have identified a mutated gene that causes breast cancer to become more aggressive and spread to other parts of the body in up to 30% of patients. The discovery provides exciting new avenues to develop new treatments for breast cancer, including more effective personalised approaches.

Hormone therapy effectively treats around two-thirds of breast cancers, but a genetic mutation occurs in some patients, which stops breast cancer from responding to treatment. But why?

In a new study published in Cancer Research journal, a team from the University of Pittsburgh School of Medicine describe how so-called ‘hotspot’ mutations in the ESR1 gene cause breast cancer to evade treatment and spread.

“A huge number of deaths in breast cancer patients are the result of mutations in estrogen receptor genes,” says Steffi Oesterreich, one of the authors of the paper. “Our study provides a deeper understanding of how these mutations contribute to disease progression and also identifies potential vulnerabilities, which we hope will lead to development of personalized treatment approaches.”

The team used liquid biopsies to analyse blood samples. When investigating them, they identified clusters of tumour cells in the bloodstream. “We think that this mutation makes tumor cells sticky, so they clump together,” said Oesterreich. The team believe that as the tumour cells travel through the bloodstream, they join onto healthy tissue, causing cancer to spread.

The team hopes that discovering the ESR1 mutation will open doors for scientists to develop new, personalised treatments for cancer. Specifically, the team believe that targeting the mutated cells with a type of immune cell known as macrophages could be effective.

The research is an exciting development in the ongoing battle against breast cancer. At RGCC, alongside developing new cancer treatments, we offer a range of personalised genetic tests to identify primary and secondary cancers. Our Metastat RGCC test uses similar techniques to detect secondary cancers, including likely locations.

You can read the full paper, Hotspot ESR1 Mutations Are Multimodal and Contextual Modulators of Breast Cancer Metastasis, here.