Fig. 1

Hypothesis of therapeutic strategies against lung cancer metastasis based on CTCs. Many common mutational gene and protein expression profiles exist among primary tumours, CTCs, and metastases. Primary tumours can reflect invisible micrometastases in response to drug therapy. Additionally, the dynamic change in the CTCs number can also reflect the growth of distant invisible micrometastases, as well as the response of invisible micrometastases, to drug therapy. Targeting CTCs to treat invisible micrometastasis may prevent metastasis and prolong the survival of lung cancer patients