We identified many differences between IBC and non-IBC cases: 54.5% versus 68.8% were estrogen receptor-positive, 39.9% versus 14.8% human epidermal growth factor receptor 2-positive, 91% versus 4% exhibited erythema, 63% versus 97% had a mass, and 57% versus 10% had mammographic evidence of skin thickening.
The 21-gene recurrence scores of subsequent early-stage, ER+ IBCs varied by race/ethnicity (P<sub>heterogeneity</sub> = .057); black women were more likely than white women to have a recurrence score of 26 or higher (HR, 1.38; 95% CI, 1.00-1.92).
The prevalence of mutations was 24% (22 of 92) among women with triple-negative IBC, 13% (13 of 99) among women with estrogen receptor- and/or progesterone receptor-positive, human epidermal growth factor receptor 2 (HER2)-negative disease, and 9.3% (10 of 108) among women with HER2-positive IBC.
Compared to the established roles of ER and PR in luminal IBC, much less is known about the roles and mechanism of action of estrogen (E2) and progesterone (P4) and their cognate receptors in the development and progression of DCIS.
HDs had significantly higher Th1 responses versus estrogen receptor (ER)<sup>pos</sup> IBC and TNBC patients across all three immune parameters; HER2<sup>pos</sup> IBC patients displayed responses similar to HDs and BDs.
Overexpression of epidermal growth factor receptors (EGFR/HER2) along with estrogen receptor (ER) negativity is common in IBC tumor cells, which instead of a solid mass present as rapidly proliferating diffuse tumor cell clusters.
However, gene set enrichment analysis (GSEA) showed that GPER signaling is ultra-activated in ER-positive IBC when compared with normal and its activation is positively associated with NHERF1 mRNA levels.
Molecular aberrations affecting the PI3K pathway may play a role in the progression from high-grade DCIS to IBC in a subset of cases (e.g., a subgroup of ER-positive/HER2-negative lesions).
This study revealed for the first time that expression alterations of DGCR8 are significantly associated with estrogen receptor and Ki-67 status in IBC.
In this study, we identified genes for normalization of RT-qPCR data for invasive breast cancer (IBC), with special emphasis on estrogen receptor positive (ER+) IBC, but also examined their applicability to ER- IBC, normal breast tissue and breast cancer cell lines.
The first cluster was mainly characterised by non-IBC specimens and IHC ER+ breast tumours (13 out of 18 and 15 out of 18 respectively), whereas the second cluster was mainly characterised by IBC specimens and IHC ER- breast tumours (12 out of 19 and 15 out of 19 respectively) (Pearson chi(2), P<0.0001 and P<0.0001 respectively).
IBC tumors were more likely to be steroid hormone receptor negative (estrogen receptor, 49% versus 30%; P=0.002; progesterone receptor, 68% versus 42%; P=0.001).