We also found that the mean serum concentration of sFRP2 in TNM stage I+II breast cancer patients was 54.4 ± 16.7 ng/mL, which was obviously higher than the mean serum sFRP2 level in normal healthy controls (34.9 ± 15.5 ng/mL, P < 0.001), which implied that sFRP2 could be beneficial in early diagnosis of breast cancer. Here, SFRP2 is linked to breast cancer.