Our results revealed similar tumor latencies for Rac1b−/−;MMTV-NIC, Rac1b+/−;MMTV-NIC and Rac1b+/+;MMTV-NIC mice (Fig. 6A), indicating that the tumor latency phenotype observed in Rac1flox/flox;MMTV-NIC and Rac1flox/+; MMTV-NIC mice is due to the loss of Rac1, not Rac1b. Here, RAC1 is linked to neoplasm.