MKI67 and esophageal squamous cell carcinoma: Previous studies have revealed that high Ki-67 is associated with good responses to chemotherapy,33,34 suggesting that highly proliferative tumors are sensitive to platinum-based chemotherapeutic drugs.34 In fact, high Ki-67 levels before chemotherapy were reportedly associated with good response to chemotherapy in breast cancer patients35,36 and patients with ESCC.37