In addition, Zalutsky and coworkers recently labeled an anti-HER2 nanobody with 211At, using this similar residualizing agent, referred to as N-succinimidyl-3-[211At]astato-4-guanidinomethylbenzoate (SAGMB).[114] Paired-label biodistribution studies directly compared the in vivo behavior of 211At-SAGMB-nanobody to that of its 131I analog SGMIB-nanobody in athymic mice, showing excellent preservation of HER2 binding after 211At labeling in combination with high internalization and optimal tumor uptake. The gene discussed is ERBB2; the disease is neoplasm.