Such pausing in mammals has not been the subject of recent investigation, although the G2-to-M transition is known to be regulated by the growth factor IGF-1—for example, in mammalian uterine cells (Adesanya et al., 1999), oligodendrocyte progenitors (Frederick and Wood, 2004; Min et al., 2012), spermatogonial stem cells (Wang et al., 2015), and multiple myeloma cells (Stromberg et al., 2006). This evidence concerns the gene IGF1 and AL amyloidosis.