RPS6 and esophageal squamous cell carcinoma: The over expression and activation of rpS6 in lymphangioleiomyomatosis-associated angiomyolipomas, pulmonary sclerosing hemangioma, dysplasia and squamous cell carcinoma of the oral cavity and esophageal squamous cell carcinoma revealed the influential roles of rpS6 either in benign or malignant tumors [15–18].