In a nutshell
The authors studied whether genes could be used to predict which patients with human epidermal growth factor receptor 2 (HER2) positive breast cancer would benefit from trastuzumab (Herceptin).
Some background
HER2 positive breast cancers depend on the HER2 protein for growth. Trastuzumab blocks HER2, and is an effective treatment for HER2 positive breast cancer. However, breast cancer still relapses (returns) in up to a quarter of patients despite trastuzumab treatment. It is suggested that genes could be associated with the risk of relapse after treatment with trastuzumab and surgery.
Methods & findings
This study examined the association between genes and the effectiveness of trastuzumab. 1282 patients were randomly assigned to one of three treatment groups. All patients received chemotherapy. Patients in treatment group A also received the chemotherapy paclitaxel (Taxol). Patients in treatment group B received paclitaxel followed by trastuzumab. Patients in treatment group C received paclitaxel and trastuzumab at the same time. Relapse free survival, the period of time until cancer returns, was measured.
Genetic analysis was carried out on the tumors from these patients. The authors identified genes related to the immune system (the system that protects the body from disease). Immune gene enrichment is a technique in genetic analysis. This was used to determine whether immune genes were associated with relapse free survival.
Immune gene enrichment increased relapse free survival by 65% in treatment groups B and C compared to patients without enrichment. Patients in treatment groups B and C who did not have immune gene enrichment did not benefit from trastuzumab. Immune gene enrichment was not associated with increased relapse free survival in treatment group A.
The bottom line
The authors concluded that increased levels of certain immune genes may be used to predict whether patients benefit from trastuzumab.
Published By :
Journal of clinical oncology
Date :
Jan 20, 2015
