0000000000868980
AUTHOR
Anna Szwajkosz
ER-/PgR+ breast cancer is a separate entity characterized by distinct phenotype: Comprehensive reevaluation of cases from Polish and Hungarian centers.
e12554 Background: ER negative (-)/PgR positive (+) breast cancer (BC) is very uncommon and questioned by many experts. We comprehensively reevaluated ER-/PgR+ BCs in the large cohort from Polish and Hungarian centers. Methods: FFPE blocks from 105 ER-/PgR+ tumors (45 breast biopsies and 64 post-operative samples from tumors not exposed to systemic therapy) were collected from 10 Polish and 3 Hungarian centers. In 60 cases available original slides with ER/PgR staining underwent reevaluation by 3 pathologists (MK, RP, WB) for ER and PgR expression by ASCO/CAP criteria. Subsequently, all samples were stained with 3 antibodies against ER (Dako monoclonal (MC) mouse anti-ERα, clone 1D5; Dako …
High expression of progesterone receptor may be an adverse prognostic factor in oestrogen receptor-negative/progesterone receptor-positive breast cancer: results of comprehensive re-evaluation of multi-institutional case series
Oestrogen receptor (ER)-negative (–) progesterone receptor (PgR)-positive (+) is the least common combination of steroid receptor expression observed in breast cancer. There are many controversies regarding the actual existence of ER–/PgR+ phenotype. In the current study, we aimed to perform comprehensive immunohistochemical re-evaluation of ER–/PgR+ breast cancers from multiple institutions. A total of 135 cases of ER–/PgR+ breast cancer were collected from 11 institutions from the period 2006–2020 and subsequently stained with three clinically validated anti-ER antibody clones: SP1 (Roche), 1D5 (Dako), and EP1 (Dako), and two anti-PgR antibody clones: 636 (Dako), and 1E2 (Roche). Clinicop…