Second, some clinical risk factors like Ki-67 index (36, 37) and BRCA1- and BRCA2- related mutation (15, 38) as well as high 21-Gene Recurrence Score (21-GRS) (39) which have been proved to be related to worse OS in patients with breast cancer were unavailable in the SEER database. This evidence concerns the gene MKI67 and breast carcinoma.