Before starting the administration of capecitabine, the expression of ERα and DPD was evaluated by immunohistochemistry, and immunohistochemical analysis demonstrated that the expression of DPD in the MCF7/T tumor was remarkably lower than that in the MCF7 tumor, indicating that the tumor created by subcutaneous inoculation of two cell lines maintained the characteristic observed in vitro (Fig 8A). Here, ESR1 is linked to neoplasm.