Several reports have highlighted the elevated expressionof CES2 in pathological tissues as compared to healthy tissues.211,212 Overexpressed CES levels in cancer cells are thought to abet invasion,migration, survival, and tumor growth.213,214 Comparedto normal cells (0.17 ± 0.09 U/L male; 0.12 ± 0.07 U/L female),about a 2–4-fold increase in CES activity in malignant colorectalcancer (0.45 ± 0.25 U/L male; 0.45 ± 0.35 U/L female) hasbeen reported.215 Hence, several esterase-responsivetheranostic agents have been developed to achieve tumor-specific imagingand improve therapeutic outcomes. This evidence concerns the gene CES2 and neoplasm.