Study Finds Genetic Mutations Differ Across Younger and Older Patients With Breast Cancer

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Women younger than age 40 with advanced breast cancer often experience more aggressive disease and worse prognoses than their older counterparts. Knowing which types of genetic mutations these patients tend to have may inform treatment strategies and improve outcomes. In a recent study, researchers investigated the genomic alterations of patients with breast cancer, uncovering differences between younger and older patients. The findings were presented by Ansari et al at the 2022 ASCO Annual Meeting (Abstract 1027).

“Knowing which genomic alterations this group of women has allows us to better tailor therapies,” said Norin Ansari, MD, a medical oncology/hematology fellow at Yale Cancer Center and lead author of the study. “It can lead to more effective treatment and better outcomes for patients.”

The researchers analyzed 2,049 breast cancer samples and compared findings across three age groups: patients younger than 30, patients aged 30 to 39, and patients aged 40 and older. Patients in the younger age groups had higher rates of BRCA1, BRCA2, and RB1 mutations and lower rates of CDH1 and PIK3CA mutations than did older patients. Differences were found to be statistically significant in BRCA1, CDH1, and PIK3CA.

“This is important information to have, because patients with different types of mutations will respond differently to the drugs we have available,” said Mariya Rozenblit, MD, Instructor of Medicine (Medical Oncology) at Yale Cancer Center and coauthor of the study.

The researchers also found the following:

  • Breast tumors were less likely to be estrogen receptor–positive in younger women and were more likely to be triple-negative.
  • There was no clear pattern in HER2-positive status by age. 
  • Younger women were more likely to have PD-L1 expression but had lower frequencies of tumor mutational burden > 10.

“These findings will help us better determine which drugs to use,” added Maryam Lustberg, MD, Associate Professor of Medicine (Medical Oncology) at Yale School of Medicine, Director of the Breast Center at Smilow Cancer Hospital and Yale Cancer Center, and senior author of the study. “They’ll give us a head start when treating young women with breast cancer.”

Disclosure: For full disclosures of the study authors, visit

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.