ESR1 and metastatic malignant neoplasm in the lymph nodes: A study at 2017 conducted a meta-analysis of 27 studies which included 10,231 patients to assess the relations of PTEN expression with clinicopathological characteristics, the PTEN loss had relations with larger tumor size (P=0.0006), lymph node metastasis (P=0.0001), negative ER (P=0.03), and negative PR (P=0.02), and reported no significant relation between PTEN loss and HER2 status (Li et al., 2017).