Expression of YY1 correlates with progression and metastasis in esophageal squamous cell carcinomas

Judong Luo,^1,* Xin Jiang,^1,* LiLi Cao,^2,* Kejun Dai,¹ Shuyu Zhang,^3,4 Xin Ge,^3,4 Xifa Zhou,¹ Xujing Lu<sup>1

1</sup>Department of Radiotherapy, Changzhou Tumor Hospital, Soochow University, Changzhou, People's Republic of China; ²Department of Molecular Radiobiology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Japan; ³School of Radiation Medicine and Protection and Jiangsu Provincial Key Laboratory of Radiation Medicine and Protection, ⁴Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions and School for Radiological and Interdisciplinary Sciences (RAD-X), Soochow University, Suzhou, People's Republic of China
 
^*These authors contributed equally to this work

Objective: Esophageal squamous cell carcinoma (ESCC) is one of the deadliest cancers worldwide. Yin Yang 1 (YY1) is a ubiquitous and multifunctional zinc-finger transcription factor that plays important biological functions in cell homeostasis and tumorigenesis. The purpose of this study was to investigate the expression of YY1 in different ESCC tissues and the potential relationship with clinicopathological features.
Methods: One hundred and four ESCC tissues were collected in this study. The protein levels of YY1 were measured by immunohistochemistry. TE-1 cell invasion in vitro was assessed using the Transwell assay.
Results: There were no obvious differences between expression levels in patients over age 64 and those younger than 64, and no noticeable distinction was observed between males and females. However, the YY1 protein level was significantly higher in ESCC tissues with lymph node metastasis than those without lymph node metastasis (P=0.042). Furthermore, the expression of the YY1 protein was stronger in stage III–IV patients than in stage I–II patients (P=0.002), but the protein levels between different histological grades (well, moderate, or poor) showed no statistical significance. Similarly, there was no difference in YY1 expression in patients with or without lymphatic invasion. The Transwell assay revealed that the overexpression of YY1 promoted the invasion ability of TE-1 cells and the inhibition of YY1 could reverse this promotion.
Conclusion: YY1 expression was associated with TNM stage and lymph node metastasis, suggesting that YY1 can influence human esophageal cancer progression and metastasis.

Keywords: immunohistochemistry, transwell assay, clinicopathological features, invasion