CCL21 and posterior cortical atrophy: The authors of the research, Maolake et al., revealed that the tumor necrosis factor-α (TNF-α) provides a huge contribution towards metastasizing PCa lymph nodes using LNCaP, DU145, LNCaP-SF, and PC3 cell lines of PCa can be seen through the activation of chemokine (C-C motif) ligand 21/CC chemokine receptor 7 (CCL21/CCR7) axis and this discovery may mediate the influence that extracellular vesicles have on metastasis through the lymphatic pathway[112].