ESR1 was downregulated in recurrent tumors in the HER2-positive subgroup (Fig. 6a), along with decreases in genes coding the phosphatase and tensin homolog, a tumor suppressor (Fig. 6b) and transforming growth factor-β (TGFβ) (Fig. 6c), a multifunctional cytokine. Here, PTEN is linked to neoplasm.