SYDNEY, Aug. 18 (Xinhua) -- Researchers in Australia have identified a key mechanism behind treatment resistance in estrogen receptor-positive (ER+) breast cancer, the most common subtype worldwide.

The study revealed why some breast cancers resist treatment, potentially opening the door to more effective therapies for patients, according to a statement released Monday by the Sydney-based Garvan Institute of Medical Research.

Scientists found that inactivation of a stress pathway makes ER+ breast cancer cells ignore stress signals and evade treatment, said the study published in Italy's Journal of Experimental & Clinical Cancer Research.

The team found that inactivating the JNK pathway enables cancer cells to resist endocrine therapy combined with CDK4/6 inhibitors, a common first-line treatment for high-risk patients.

The JNK pathway acts as a cellular alarm, triggering damaged cells to stop dividing or self-destruct in response to stress, such as cancer treatments, said the study.

"When we knocked out genes involved in the JNK pathway, cancer cells continued to grow despite treatment...These cells also spread to form more metastases in preclinical models," said the study's first author Sarah Alexandrou from the Garvan Institute and Australia's University of New South Wales (UNSW).

This resistance was observed both in laboratory experiments and in tumor samples from patients, where low JNK activity was correlated with poor response to therapy, the study showed.

Co-author Associate Professor Liz Caldon from the Garvan Institute and the UNSW highlighted that screening for JNK pathway activity could predict which breast cancer patients won't benefit from standard therapy, enabling more personalized treatment. ■