Previous GWAS hits in relation to young-onset breast cancer

Breast cancer is one of the most prevalent cancer types but luckily, most of the times, it is curable, particularly if diagnosed in early stages. The risk of developing breast cancer is also predictable based on genetic factors, family history, etc. thanks to several Genome wide association studies (GWAS) which revealed the genetic markers associated with Breast cancer. However, not too many studies are available on genetic markers of Young-onset breast cancer (YOBC). Since the underlying mechanism of YOBC could be different from breast cancer in older ages, scientists in this study aimed to test if previously identified GWAS hits on breast cancer are also associated with YOBC or not? Either individually or through a joint effect with each other’s?

In order to do that, they studied 1279 YOBC cases (age less than 50 years old at the diagnosis) and compared them with their family members who did not develop YBOC. Through genotyping, they got the genetic data on 77 previously reported GWAS hits on breast cancer for their own study population. They showed that 17 of those hits are independently associated with YOBC and in joint effect their effect are not following the additive effect but more close to multiplicative effects.

Researchers of this study, finally suggested that their genetic risk score could be used as a tool to differentiate between lower risk women and higher risk women who needs to be monitored and screened earlier and more frequently for YOBC.

Original article: Shi et al (2016) Breast Cancer Res Treat. 2017 Jan;161(2):333-344. doi: 10.1007/s10549-016-4053-z