TP53 and colorectal carcinoma: Moreover, the pharmacological (UBF-interacting Ca2+ chelators) or genetic (siRNA) inhibition of 45S pre-rRNA synthesis in nine human CRC cell lines was associated with p53 protein stabilization, cell cycle arrest, and apoptosis, suggesting that inhibition of rRNA synthesis promotes the tumor suppressive response and thus might be an early step in colorectal tumorigenesis [87].