Nonmuscle myosin IIA is associated with poor prognosis of esophageal squamous cancer

Nonmuscle myosin IIA (myosin IIA) is a force-producing protein involved in the process of cell migration. Its expression has been considered as a bad prognostic indicator in stage I lung adenocarcinoma. However, the expression and clinical significance of myosin IIA in esophageal cancer has not been explored. In this study, we investigate the expression level of myosin IIA in 50 esophageal squamous cancer and 30 adjacent normal esophageal tissues by immunohistochemical staining and correlated its expression with clinicopathological features. Myosin IIA was expressed in all esophageal squamous cancer tissues (100%) and 8 of 30 adjacent normal tissues (26.7%, P = 0.000). In cancer tissues, elevated myosin IIA expression level was significantly correlated with increasing metastatic lymph nodes, poorer cancer differentiation, and advanced tumor stage. Further univariate analysis suggested that strong myosin IIA expression was associated with a significantly shorter overall survival (P = 0.021). In addition, MYH9 SiRNA was transfected into esophageal squamous cancer cell line (KYSE-510) to study the role of myosin IIA in cell migration. SiRNA-mediated depletion of myosin IIA in KYSE-510 cells significantly increased cell-matrix adhesion and attenuated cell migration ability (P = 0.000). In conclusion, these findings indicate that overexpression of myosin IIA may contribute to the progression and poor prognosis of esophageal squamous cancer, and this effect may be associated with increased cancer cell migration.