American and Spanish researchers have found potential ways for doctors to improve the treatment of hormone receptor-positive breast cancer even if they lack access to costly multi-gene tests, as they report at the 4th IMPAKT Breast Cancer Conference.
Because breast cancer is a biologically and clinically varied disease, doctors aim to choose appropriate treatments based on the characteristics of each patient's individual tumor. In the past, this has been done using pathology-based biomarkers; however these do not capture the full diversity of cancers.
"In this context, tests based on multi-gene expression have been shown to provide valuable information beyond the pathology-based biomarkers," says Dr Aleix Prat from the University of North Carolina, Chapel Hill. "However, multi-gene tests are not readily available in most of the world due to cost, assay turnaround times and other logistic issues."
Dr Prat and colleagues addressed this problem by trying to improve the current pathology-based biomarkers to better represent data coming from a particular multi-gene test known as the PAM50 breast cancer intrinsic classifier.
"The PAM50 breast cancer intrinsic classifier identifies two major groups of hormonal receptor-positive breast cancer known as the Luminal A and Luminal B subtypes. These two molecular entities have different risks of relapse and responses to chemotherapy," Dr Prat said.
Alongside the development of this multi-gene assay, clinicians have devised pathology-based surrogate assays for the identification of both the Luminal A and Luminal B subtypes. "In the absence of multi-gene assays, the pathology-based assays are clinically valuable," Dr Prat explained. "However, we observed that the current pathology-based definitions of the Luminal A and Luminal B subtypes still show a 30-40% discordance rate compared to multi-gene tests such as the PAM50 breast cancer intrinsic classifier."
|Contact: Vanessa Pavinato|
European Society for Medical Oncology