PTEN and breast cancer: In detail, results from a biomarker analysis of 764 samples from the Breast International Group 1–98 (which randomized post-menopausal HR+ early BC patients to receive in the adjuvant setting tamoxifen, letrozole or the sequential treatment with letrozole followed by tamoxifen) revealed a non-significant trend towards increased risk of distant recurrence for patients with tumors harboring a PTEN mutation by next-generation sequencing, as compared with patients with wild-type PTEN (HR 1.67, 95% CI 0.69–4.06, p = 0.26) [27].