Since the presence of lymph node metastasis can worsen the prognosis of a malignancy, it could be concerning that certain cancer cells upregulate their CCR7 and detach from the primary tumor, perhaps in response to the CCL21 gradient, which promotes directed migration (chemotaxis) to and through lymphatic vessels. The gene discussed is CCL21; the disease is metastatic malignant neoplasm in the lymph nodes.