PMAIP1 and hepatocellular carcinoma: On the other hand, Noxa, a proapoptotic factor that is characterized in several human cancer cell lines,12 is regulated by SAG-UPS.13SAG overexpression has been observed in liver cancer, although in one sample.13 However, no information is thus far available on the potential involvement of key apoptotic factors regulated by SAG-UPS, particularly from HCC patient samples.