SFRP1 and melanoma: To assess sFRP1 inhibition–induced dormancy, aged C57BL/6 mice were intradermally injected with melanoma cells. After three weeks, mice received intraperitoneal anti-sFRP1 antibody or IgG control for two weeks. Lung tissues were analyzed by H&E and IHC for MITF and Ki-67. Reduced Ki-67 and increased single MITF+ cells indicated dormancy induction.