KIF22 and gastric cancer: A growing number of studies have evidenced that KIF22 has significantly high expression in several tumor types, such as esophageal squamous cell carcinoma, gastric cancer, and bladder cancer.11, 12, 13 It is worth noting that KIF22 is required for the invasion of melanoma cells, and the knockdown of KIF22 inhibits the invasion of melanoma cells.14