Although an in vivo murine study using systemic administration of the PAI‐1 inhibitor SK‐216 for lung cancer and melanoma indicated that PAI‐1 generated by host rather than tumor cells plays a determinant role in the anticancer effect,31 further accumulation of biomarker data in patients with mRCC treated with axitinib is warranted to verify the results. This evidence concerns the gene SERPINE1 and neoplasm.