SUB1 protein has important roles in various cellular processes including transcription, replication, chromatin organization, cell cycle progression, DNA damage repair and apoptosis.20, 21, 34, 52 Earlier, it was shown that SUB1 is amplified and overexpressed in non-small-cell lung cancer cell lines,53 invasive intraductal papillary mucinous neoplasm of the pancreas54 and in carcinomatoses.55 Additionally, it has been shown that exogenous overexpression of SUB1 could induce the transformation of a population of normal dermal multipotent fibroblasts to acquire malignant characteristics of anchorage-independent growth in vitro and tumorigenicity in nude mice.56 Additionally, it was reported that SUB1 is upregulated in esophageal squamous cell carcinoma and its absence increased radiosensitivity of esophageal squamous cell carcinoma cells, and suppressed non-homologous end-joining activity via downregulation of XLF.52 Targeting coactivators and transcription factors through chemical inhibitors has been challenging.57, 58, 59, 60