MCL1 and hydrops fetalis: Additionally, we observed that undifferentiated and immature differentiated progeny show similar expression levels (mRNA levels) of other apoptosis-regulating factors such as bcl-w, bcl-xL, mcl-1, puma and bax. We also determined that HF exhibit lower levels of puma mRNA and higher levels of blc-w transcript than the rest of the analyzed cell lines.