Several signaling pathways, such as PI3K [23], FAK [24], NF-κB [25], JAK/STAT3 [26] and the HIF-1α/VEGF signaling pathway [27], have been implicated in the process of lymphangiogenesis during cancer metastasis, among which the HIF-1α/VEGF signaling pathway is considered one of the key pathways associated with lymphangiogenesis and metastasis. Here, PTK2 is linked to cancer.