The difference in tumor uptake of [99mTc]Tc-C51 in the melanoma tumor model, at 1.44 ± 0.11%IA/g, compared to 4.96 ± 1.4%IA/g in the GBM model, can be attributed to differences in in vivo B7-H3 expression. The gene discussed is CD276; the disease is neoplasm.