Epithelial mesenchymal transition in early invasive breast cancer: an immunohistochemical and reverse phase protein array study

Abstract

Epithelial mesenchymal transition (EMT), as defined by loss of epithelial characteristics and gain of a mesenchymal phenotype, has been reported in vivo although the occurrence of events remains unclear. This study aims at exploration of EMT portraits of breast cancer (BC) with relevance to different molecular pathways, especially potential EMT triggers and BC molecular subtypes. Immunohistochemical (IHC) expression of markers/triggers of EMT was studied on a well-defined cohort of invasive non-lobular BC (n = 1,035), prepared as tissue microarrays. IHC panel of biomarkers included cadherins (cad; E-cad and N-cad), TGFβ1, PIK3CA, pAkt, and others. Reverse phase protein array (RPPA) was performed for quantitative analysis of proteins extracted from formalin fixed paraffin embedded tissues of a subset of cases from this cohort. Four combinatorial phenotypic groups representing cadherin switch were defined, including E-cad(+)/N-cad(-), E-cad(-)/N-cad(-), E-cad(+)/N-cad(+), and E-cad(-)/N-cad(+). Statistically significant association was noticed between these phenotypes and histological tumour grade, tumour type and size and NPI staging classes. The E-cad/N-cad switch occurred more frequently in the triple negative molecular class, both basal and non-basal, and in the HER2(+) subtype than in luminal BC. Significant outcome differences were observed between cadherin switch combinatorial groups regarding BCSS and DMFS (p < 0.001). Results of RPPA confirm those observed using IHC regarding differential expressions of EMT markers/triggers. EMT/cadherin switch programs in BC appear to occur in synergy with TGFβ1 and PIK3/Akt pathways activation. These data explain, at translational proteomic level, the molecular heterogeneity and in turn the varied clinical behaviour of BC molecular subtypes. RPPA is a promising high-throughput technique in monitoring subtle quantitative changes in protein expression in archival material.

Markers of progression in early-stage invasive breast cancer: a predictive immunohistochemical panel algorithm for distant recurrence risk stratification

“…These results support recommendations of using these two makers, beside ER, PR and HER2 negativity, as additional surrogates in characterising breast cancers with basal phenotype [25]. Moreover, the roles played by PIK3CA in BC progression through its downstream effectors, especially through driving an epithelial-to-mesenchymal transition program (EMT) with up regulation of N-cadherin and P-cadherin has been reported in the same series [26,27], as well as in others [28].…”

EMT Transition Alters Interstitial Fluid Flow–Induced Signaling in ERBB2-Positive Breast Cancer Cells

“…To test this idea specifically, we showed that induction of EMT in NeuN converted the IFF invasion response from chemokineindependent to chemokine receptor-dependent. Previous studies have implicated ERBB2 expression and activation in EMT (31,48,49), therefore our findings could suggest that the observed EMT-specific response to IFF was related to expression of HER2. Although the HER2 pathway is constitutively active in NeuT, both cell lines overexpress similar levels of HER2 so this alone could not explain the differential effects of IFF on these cells.…”

Clinical and biological significance of glucocorticoid receptor (GR) expression in breast cancer

“…RPPA methodology was done as previously described [40][41][42][43]. In brief, the lysates prepared in RIPA buffer were solubilised in 4XSDS sample buffer and loaded onto a 384-well plate (Genetix, UK), where each sample was two-fold serially diluted three times in 19 SDS buffer.…”