QKI and cancer: However, the structure of the entire STAR domain with bound RNA remains unknown, especially in cancer cells.12 A previous study showed that QKI directly regulates the expression of p27 and cyclinD1 to form a negative feedback loop with E2 transcription factor 1 (E2F1), indicating that QKI may be involved in cell cycle regulation and cell differentiation.13 More recent studies demonstrated that QKI possesses tumour suppressor activity in various human cancers, including glioblastoma, and prostate, colon, lung, gastric, oral and kidney cancers.9, 11, 14, 15, 16, 17, 18