Increased tumor uptake of both B9-ABD tracers couldnot efficientlybe blocked by administration of unlabeled girentuximab, which bindsa similar epitope of CAIX, indicating that the uptake is partly CAIX-independent.Autoradiography analysis indeed confirmed tracer uptake of ABD-conjugatesin CAIX-negative keratinized tumor tissue, hypothetically due to increasedresidence of plasma proteins, possibly including albumin in this tissuetype. Here, CA9 is linked to neoplasm.