Figure 1. Flow chart of study selection.
(CNKI, Chinese National Knowledge Infrastructure; SNP, single nucleotide polymorphism; BC, breast cancer.).
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.