Since protracted inflammation with elevated COX-2 activity is a key factor underlying biopsy-associated pro-metastatic changes [13], we mimicked the clinically used biopsy-site marker to explore a novel preventive strategy in tumor-bearing mice to achieve sustained release of celecoxib into the biopsy cavity from PLA-gel loaded with Cx-NPs (Cx-NP/PLA-gel; Fig. 1b). Here, PTGS2 is linked to neoplasm.