ESR1 and in situ carcinoma: However, results from the subgroup analyses based on menopausal status (n = 10 for premenopausal and n = 11 for postmenopausal) or cancer characteristics (n = 3 for carcinoma in situ only, n = 2 for estrogen receptor‐positive only, and n = 2 for estrogen receptor‐negative only) did not yield significant results at all.