In addition to the spatiotemporal regulation and dynamic replacement of subunit RPC7α with RPC7β during early development, POLR3G expression re-emerges in proliferative and transformed cells, in line with the discovery of both Pol IIIA and IIIB in mouse myeloma tumor cells (Schwartz et al., 1974; Haurie et al., 2010). The gene discussed is POLR3G; the disease is plasma cell myeloma.