KDR and carcinoma: In support of our findings, it has already been determined that some TKIs suppress HIF‐1α synthesis under hypoxic conditions and inhibit tumor infiltrating Tregs in several carcinomas of humans, suggesting that it might be a principal mechanism of action.10, 11, 12, 13 In clinical research in humans, an increase in tumor‐infiltrating Tregs and high expression of HIF‐1α and VEGFR have been reported to be correlated with tumor recurrence or distant metastasis.6, 7, 8