Form follows function: Morphological and immunohistological insights into epithelial-mesenchymal transition characteristics of tumor buds.
Tumour biology : the journal of the International Society for Oncodevelopmental Biology and Medicine. 2017;(5):1010428317705501
In cancer biology, the architectural concept "form follows function" is reflected by cell morphology, migration, and epithelial-mesenchymal transition protein pattern. In vivo, features of epithelial-mesenchymal transition have been associated with tumor budding, which correlates significantly with patient outcome. Hereby, the majority of tumor buds are not truly detached but still connected to a major tumor mass. For detailed insights into the different tumor bud types and the process of tumor budding, we quantified tumor cells according to histomorphological and immunohistological epithelial-mesenchymal transition characteristics. Three-dimensional reconstruction from adenocarcinomas (pancreatic, colorectal, lung, and ductal breast cancers) was performed as published. Tumor cell morphology and epithelial-mesenchymal transition characteristics (represented by zinc finger E-box-binding homeobox 1 and E-Cadherin) were analyzed qualitatively and quantitatively in a three-dimensional context. Tumor buds were classified into main tumor mass, connected tumor bud, and isolated tumor bud. Cell morphology and epithelial-mesenchymal transition marker expression were assessed for each tumor cell. Epithelial-mesenchymal transition characteristics between isolated tumor bud and connected tumor bud demonstrated no significant differences or trends. Tumor cell count correlated significantly with epithelial-mesenchymal transition and histomorphological characteristics. Regression curve analysis revealed initially a loss of membranous E-Cadherin, followed by expression of cytoplasmic E-Cadherin and subsequent expression of nuclear zinc finger E-box-binding homeobox 1. Morphologic changes followed later in this sequence. Our data demonstrate that connected and isolated tumor buds are equal concerning immunohistochemical epithelial-mesenchymal transition characteristics and histomorphology. Our data also give an insight in the process of tumor budding. While there is a notion that the epithelial-mesenchymal transition zinc finger E-box-binding homeobox 1-E-Cadherin cascade is initiated by zinc finger E-box-binding homeobox 1, our results are contrary and outline other possible pathways influencing the regulation of E-Cadherin.
Prognostic significance of Zinc finger E-box binding homeobox 1 (ZEB1) expression in cancer cells and cancer-associated fibroblasts in pancreatic head cancer.
BACKGROUND Pancreatic ductal adenocarcinoma (PDAC) is characterized by an aggressive biology and poor prognosis. Experimental evidence has suggested a role for the transcriptional repressor Zinc finger E-box binding homeobox 1 (ZEB1) in epithelial-mesenchymal transition, invasion, and metastasis in PDAC. ZEB1 expression has been observed in cancer cells as well as stromal fibroblasts. Our study aimed to evaluate the prognostic value of ZEB1 expression in PDAC tissue. METHODS Patient baseline and follow-up data were extracted from a prospectively maintained database. After clinicopathologic re-review, serial sliced tissue slides were immunostained for ZEB1, E-cadherin, vimentin, and pan-cytokeratin. ZEB1 expression in cancer cells and adjacent stromal fibroblasts was graded separately and correlated to routine histopathologic parameters and survival after resection. RESULTS A total of 117 cases of PDAC were included in the study. High ZEB1 expression in cancer cells and in stromal cancer-associated fibroblasts was associated with poor prognosis. There was also a trend for poor prognosis with a lymph node ratio of greater than 0.10. In line with its role as an inducer of epithelial-mesenchymal transition, ZEB1 expression in cancer cells was positively correlated with Vimentin expression and negatively with E-Cadherin expression. In multivariate analysis, stromal ZEB1 expression grade was the only independent factor of survival after resection. CONCLUSION Our data suggest that ZEB1 expression in cancer cells as well as in stromal fibroblasts are strong prognostic factors in PDAC. Stromal ZEB1 expression is identified for the first time as an independent predictor of survival after resection of PDAC. This observation suggests that therapies targeting ZEB1 and its downstream pathways could hit both cancer cells and supporting cancer-associated fibroblasts.