RPS6KB1 and esophageal squamous cell carcinoma: Likewise, despite a considerable degree of heterogeneity in IHC-positive cases across the different studies analysed, a meta-analysis of 915 ESCC patients showed that mTOR and p-mTOR and high expression of the mTOR targets p-p70S6K and p-4E-BP1 are significantly correlated with unfavourable disease progression and survival [53].