Epithelial cells in bone marrow: do they matter?

Down-regulation of CDH1 is associated with expression of SNAI1 in colorectal adenomas

INTRODUCTION

Down-regulation of E-cadherin (CDH1) and epithelial-mesenchymal transition (EMT) are considered critical events for invasion and metastasis of colorectal carcinoma. Here we tested whether the important regulators of E-cadherin expression SNAI1 and TWIST1 are already detectable in human colorectal adenomas.

METHODS

RNA was extracted from a set of randomly selected formalin-fixed and paraffin-embedded (FFPE) colorectal adenomas (n = 41) and normal colon mucosa (n = 10). Subsequently mRNA expression of CDH1, CDH2, SNAI1 and TWIST1 was analysed by quantitative RT-PCR analysis. CDH1 as well as SNAI1 protein expression were assessed by immunohistochemistry (IHC).

RESULTS

SNAI1 mRNA was expressed in 78% (n = 32/41), TWIST1 mRNA in 41% (n = 17/41) and CDH2 mRNA in 41% (n = 17/41) of the colorectal adenoma tissue, while normal colon mucosa was negative for these transcription factors. We found a significant correlation between reduced CDH1 and the presence of SNAI1 mRNA expression and for combined SNAI1 and TWIST1 mRNA expression, respectively. A correlation between CDH2 mRNA expression and reduced CDH1 expression was not observed. We confirmed the relationship between SNAI1 expression and reduced E-cadherin expression on the protein level via IHC.

CONCLUSION

Our data show that SNAI1 and Twist1 are already expressed in benign precursor lesions of colorectal cancer and that SNAI1 expression was significantly correlated with lower expression of CDH1. Whether these findings reflect true EMT and/or are a sign of a more aggressive biology need to be investigated in further studies.

Prognostic factors in adenocarcinoma of the esophagus or gastroesophageal junction

The incidence of adenocarcinoma of the esophagus is rising rapidly in Western Europe and North America. It is an aggressive disease with early lymphatic and hematogenous dissemination. TNM cancer staging systems predict survival on the basis of the anatomic extent of the tumor. However, the adequacy of the current TNM staging system for adenocarcinoma of the esophagus or gastroesophageal junction (GEJ) is questioned repeatedly. Numerous prognostic factors have been described, but are not included in the TNM system. This review describes clinical parameters, aspects of operative technique, response to preoperative chemoradiotherapy therapy, complications and established pathologic determinants found in the resection specimen that have a prognostic impact. Furthermore, their potential application in the clinical setting in patients with adenocarcinoma of the esophagus or GEJ is discussed. Future directions to improve staging systems are given.