suggestive of significanceP = 0.0074
The CYP2D6 gene was significantly associated with plasma concentrations of endoxifen ( P = 0.0008) and suggestive of significance for 4‐OH‐Tam ( P = 0.0074); individuals with higher activity scores had increased circulating endoxifen (Figure 2 a) and 4‐OH‐Tam (Figure 2 b) levels.