fig1

Figure 1. Dormancy in cancer progression. Tumor cells can leave the primary tumor site and enter the systemic circulation as circulating tumor cells (CTCs). Once surviving CTCs have reached a target organ, they seed into a new tissue as disseminated tumor cells (DTCs). Their fate is diverse depending on their cell autonomous capacities and complementary cues provided by the local environment. DTCs can rapidly die if they fail to adapt to the new condition or are killed by the immune system. They can immediately resume proliferation if they have acquired full autonomy for cell survival and proliferation or the local microenvironment provide missing complementary cues. In addition, proliferating cells have to evade the immune system. Alternatively, DTC or small tumor cell clusters, can enter a state of dormancy if cell autonomous or microenvironmental signals are sufficient to maintain survival but do not effectively support growth or the immune system keeps them in check by preventing their expansion. Dormant tumor cells can eventually die by exhaustion, be killed by the immune system or resume proliferation and generate clinically relevant metastases at later time points