Interestingly, stratified analyses according to the site of the tumor relapse revealed similar pooled ERα discordance proportions in the case of loco-regional and metastatic recurrences, while discordance proportions for PgR expression were lower in loco-regional tumor recurrences (26%; 95% CI: 21–32%) than in distant metastases (41%; 95% CI: 37–45%). This evidence concerns the gene ESR1 and neoplasm.