The COX-2 protein, encoded by the PTGS2 gene, is related to tumor progression in adult and pediatric cancer. In neuroblastoma (NB), COX-2 was associated with loss of heterozygosity on the long arm of chromosome 11 (Ch11q loss of heterozygosity, LOH), defining a subset of aggressive disease. The present study aimed to investigate the protein expression of COX-2 in a set of 82 pre-chemotherapy (CT) and 20 post-CT NB specimens and its correlation with clinical and genomic data. A systems biology approach elucidated the network interaction of PTGS2 and other inflammation-related genes with those codified in the Ch11q deleted regions. The results indicated a significantly higher expression of COX-2 in post-CT samples. In addition, a significant positive correlation between the presence of aberrations in Ch11q and COX-2 levels and an indirect connection between the COX-2 gene and extracellular matrix remodeling (ECM)-related proteins were observed. Our findings suggest that deregulation of ECM proteolysis in Ch11q–deleted NB could elicit stromal alterations, triggering inflammatory responses via COX-2 overexpression, ultimately supporting NB progression.