The lymph node microenvironment and its role in the progression of metastatic cancer

• Lymphatic endothelial cells and vessels participate in tumor cell metastasis.
• The immunosuppressive premetastatic lymph node assists in tumor colonization.
• The metastatic lymph node undergoes remodeling that impacts growth of cancer cells.
• Tumor lesions in the lymph node are polyclonal.
• Tumor lesions mostly represent the genetic composition of the primary tumor.
• The ability of tumor cells residing in the lymph node to colonize distant organs is controversial.

Lymph nodes are initial sites for cancer metastasis in many solid tumors. However, their role in cancer progression is still not completely understood. Emerging evidence suggests that the lymph node microenvironment provides hospitable soil for the seeding and proliferation of cancer cells. Resident immune and stromal cells in the lymph node express and secrete molecules that may facilitate the survival of cancer cells in this organ. More comprehensive studies are warranted to fully understand the importance of the lymph node in tumor progression. Here, we will review the current knowledge of the role of the lymph node microenvironment in metastatic progression.