SMAD6 and ovarian cancer: The high node was composed of INHBC: rs2228225 AA and SMAD6: rs4147407 CT+TT and indicated the highest risk of ovarian cancer, with an OR of 6.33 (95%CI, 2.32–17.28; P = .0003), suggesting that the genetic variant of SMAD6: rs4147407 was a major determinant to switch the trend of lowest risk to highest risk of ovarian cancer (Figure 2 and Table 5).