CTSS and neoplasm: This 2.8-fold change between cancerous and background healthy tissue stands in line with other fluorescent Turn-ON probes, that were clinically evaluated, such as ratiometric protease-activatable AVB-620 15 and higher than that of LUM015, a cathepsin-activatable polymeric probe that showed a 1.8 tumor-to-skin ratio on murine colorectal cancer model 71.