HIF1A and neoplasm: As the expression of Ccl5 was mostly reduced (about 5‐folds) in HIF‐1α KO fibroblasts and up‐regulated (about 2.5‐folds) in HIF‐1α MOCK fibroblasts treated with hypoxia (Figure 5C), we speculated that CCL5 might play important roles in the promotion of tumour cell growth.