PIM1 and hepatoblastoma: To this end, we monitored PIM1 mRNA levels in serum-starved HeLa (human cervical adenocarcinoma), HepG2 (human hepatoblastoma), and MDA-MB-231 (human breast adenocarcinoma) cells, then measured changes in PIM1 mRNA expression as a function of time following mitogenic stimulation using serum+TPA.