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Breakthrough Identifies Genetic Mutations Behind Breast Cancer Treatment Resistance

Scientists discover gene variants linked to treatment-resistant breast cancer in young women, paving the way for personalized therapies.

Personalized breast cancer treatments could be on the horizon after a breakthrough by scientists.

Genetic mutations have been identified that shed fresh light on why patients with the most common form of the disease don’t respond to treatment.

The finding applies to young women – a population group more likely to develop aggressive tumors.

Senior author Dr. Svasti Haricharan, of Sanford Burnham Prebys Medical Discovery Institute, San Diego, said: “It is well established that as you get older, you’re more likely to develop cancer.

“But we’re finding that this may not be true for all cancers depending on a person’s genetic makeup.

“There may be completely different mechanisms driving cancer in younger and older people, which requires adjusting our view of aging and cancer.”

Patients are usually offered surgery and chemotherapy or radiation treatment before taking hormone-blocking drugs for up to a decade, to try and prevent recurrence.

But as many as a third of patients with stage two disease and over half of the patients with more advanced disease will see it come back, often years later.

The research, published in the journal Science Advances focused on estrogen receptor-positive, HER2 (ER+/HER2) breast cancer – the most common type of breast cancer.

Patients are usually offered surgery and chemotherapy or radiation treatment before taking hormone-blocking drugs for up to a decade, to try and prevent recurrence. PHOTO BY TARA WINSTEAD/PEXELS 

It is usually treated with hormonal therapies. For some patients, these treatments don’t work.

About 20 percent of tumors resist from the very beginning, and up to 40 percent develop resistance over time.

Explained Dr. Haricharan: “Understanding how certain forms of breast cancer develop in a way that makes them eventually resist therapy can help us better classify the disease.

“It may also help clinicians adjust the treatment plans for patients who will likely experience resistance to standard treatments. For scientists like myself, it can help guide research to develop new therapies to overcome these obstacles.”

Analysis of a large database of patients revealed that in ER+/HER2, gene variants had a strong link to successful treatment – with effects dependent on age.

Some were only associated with treatment-resistant breast cancer in younger women.

Dr. Haricharan said: “This was a strange finding, so much so that we almost didn’t believe it at first. But the same patterns emerged over and over again in database after database.”

The genes were involved in replication, the process by which cells grow and divide. They are responsible for repairing mistakes when they happen – a process that goes awry in virtually all cancers.

Dr. Haricharan said: “Cell cycle dysregulation occurs so early in the development of cancer that we generally don’t consider whether the individual mutations that cause cell cycle dysregulation can affect cancer’s eventual response to treatment or its ability to spread.”

By connecting the specific type that triggers cancer with the outcome of the disease many years after diagnosis, the US team proposes an entirely new paradigm for thinking about and studying all types of cancer.

Dr. Haricharan said: “This is a radical shift in how we look at cancer, which could have implications well beyond breast cancer.”

They looked at the effect of cell cycle mutations on patient outcomes in other types of cancer.

The mode of cell cycle dysregulation is significant for cancer in women, but less so for cancer in men – suggesting it could depend on sex as well as age.

Added Dr. Haricharan: “These findings emphasize why it is important to study cancer in the context of the life history of the patient.

“Too often, cancer research is focused narrowly on cells in a petri dish, forgetting the whole, complex host system in which these cells transform and grow.”
Produced in association with SWNS Talker

Edited by Saba Fatima

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