Protocadherin B9 Is Associated with Human Esophageal Squamous Cell Carcinoma Progression

Abstract

<b><i>Introduction:</i></b> Esophageal cancer is the sixth leading cause of cancer-related death worldwide. However, molecular targeted therapy and novel therapeutic targets are needed for esophageal squamous cell cancer (ESCC). In a previous study, we reported that protocadherin (PCDH) B9 plays an important role in several cancers. Therefore, in this study, we examined the clinical significance of PCDHB9 expression in ESCC. <b><i>Methods:</i></b> PCDHB9 expression was examined using immunohistochemistry in 128 cases and using quantitative reverse transcription-polymerase chain reaction in 16 cases of ESCC. PCDHB9 function in ESCC cells was examined using RNA interference. <b><i>Results:</i></b> High PCDHB9 expression was identified in 5 of 16 (31.3%). In total, 51 (40%) ESCC cases showed strong PCDHB9 expression, whereas nonneoplastic mucosa rarely showed its expression. High PCDHB9 expression was significantly associated with T classification, N grade, and stage in ESCC. In ESCC cell lines, PCDHB9 knockdown affected cell growth, migration, and adhesion. Further, the expression of integrin <i>(ITG) A3</i>, <i>ITGA4</i>, <i>ITGA5</i>, <i>ITGB1</i>, <i>ITGB6</i>, <i>vimentin</i>, <i>snail family transcriptional repressor 1,</i> and cadherin 2 (<i>NCAD</i>) was significantly reduced and cadherin 1 was significantly increased in PCDHB9 knockdown ESCC cells. <b><i>Conclusion:</i></b> These results suggest that PCDHB9 plays a tumor-promoting role and is a potential biomarker and therapeutic target in ESCC.