Table 1.

Molecular and cellular processes involved in tumor lymphatic invasion in relation to other functions in ontogeny, steady-state or pathological conditions.

Process	Role in LVI	Other Functions
EMT	Increased invasiveness and tissue infiltration of tumor cells.	Essential for ontogeny, wound healing, etc.
LEC-derived chemokine gradients.	Guidance of disseminating tumor cells towards/into initial lymphatic vessels.	Guidance of DCs and other immune cells towards/into initial lymphatic vessels.
Destabilization of lymphatic endothelial junctions.	Promotion of tumor trans-endothelial migration into the lymphatic lumen.	Unknown. Potentially involved in the regulation of lymphatic transport in inflammatory conditions.
Formation of entry gates (CCIDs) by LEC-repulsive signals.	Promotion of tumor cell cluster entry into lymphatic vessels.	Lymphatic entry of neutrophils in inflammatory conditions.