PTGS2 and cancer: Rank correlation analysis to assess whether the enhanced COX-2/iNOS expression in cervical cancer cells was associated with GM-CSF unexpectedly showed that the expression of GM-CSF in cancer tissues had a significantly negative correlation with COX-2 (r = −0.500, p < 0.05) and iNOS (r = −0.473, p < 0.01) (Table 3).