CHEK2 and esophageal squamous cell carcinoma: Samples with high MALAT1 level (> mean value, and over-expressed in ESCC) showed relatively lower levels of ATM-CHK2 pathway phosphorylation (Figure 5B), suggesting a negative correlation between MALAT1 expression and phosphorylation of the ATM-CHK2 pathway in ESCC tissues, which is consistent with results from cell lines.