PTGS2 and cancer: Regarding COX-2 extent of labeling (Table 5), 6/77 (7.7%) tumors presented with more than 50% of labeled cells, corresponding to 6/38 (15.7%) malignant tumors; 26/77 (33.8%) tumors presented with between 21 and 50% of labeled cells, corresponding to 18/38 (47.4%) malignant tumors and 8/39 (20.5%) benign tumors; 11/77 (14.3%) tumors, presented with 6–20% of labeled cells, corresponding to 8/38 (21.1%) malignant tumors and 3/39 (7.7%) benign tumors; 1/77 tumors (1.3%) presented with 1–5% of labelled cells, corresponding to 1/38 (2.6%) malignant tumors.