Estrogen receptor variants in ER-positive basal-type breast cancers responding to therapy like ER-negative breast cancers.

ABSTRACT: Immunohistochemically ER-positive HER2-negative (ER+HER2-) breast cancers are classified clinically as Luminal-type. We showed previously that molecular subtyping using the 80-gene signature (80-GS) reclassified a subset of ER+HER2- tumors to molecular Basal-type. We report here that molecular reclassification is associated with expression of dominant-negative ER variants and evaluate response to neoadjuvant therapy and outcome in the prospective neoadjuvant NBRST study (NCT01479101). The 80-GS reclassified 91 of 694 (13.1%) immunohistochemically Luminal-type tumors to molecular Basal-type. Importantly, all 91 discordant tumors were classified as high-risk, whereas only 66.9% of ER+/Luminal-type tumors were classified at high-risk for disease recurrence (i.e., Luminal B) (P?

SUBMITTER: Groenendijk FH 

PROVIDER: S-EPMC6472385 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature