DTCs in the bone marrow

DTCs in the bone marrow have been detected for all solid tumor types, suggesting that this compartment might be a preferred reservoir for blood-borne DTC from where they may re-disseminate to other distant organs such as liver or lungs where better growth conditions may exist.

For example, DTCs are prognostic markers in colorectal cancer even though bone metastases are very rare in this cancer type (Lindemann et al, 1992; Pantel et al, 1993).

In breast cancer, where bone metastases are more frequent, DTCs in the bone marrow may predict metastatic relapse in other organs as well (Braun et al, 2000, 2005).

However, it cannot be excluded that DTCs may home equally well to other organs such as lung or liver, where however they may not be so easily detected as in bone marrow.

The observed correlation between DTCs in bone marrow and local relapse in breast cancer (Bidard et al, 2008) is consistent with the recent experimental findings in mice that these cells might even re-infiltrate their primary organs and promote tumor progression (Kim et al, 2009).

If the bone marrow is a preferred reservoir for DTCs, drugs targeting the BM–tumor interactions (e.g., bisphosphonates or antibodies to the RANK ligand (Lewiecki, 2011; Gronich & Rennert, 2013)) might help to prevent metastatic or even local relapse.

Open references

 Pantel K, 2015. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4309663/