[The immunohistochemical expression of cyclooxygenase 2 is inversely associated with (18)F-FDG-PET SUV values in non-small-cell lung cancers. Initial results].

OBJECTIVE

To study the expression of COX-2 and its possible relationship with the maximum standardized uptake value (SUV) in FDG-PET, and EGFR, p16 and MIB1 expression in patients with NSCLC.

MATERIAL AND METHOD

45 patients (12 adenocarcinomas and 33 squamous cell carcinomas) were included in this study; the immunohistochemical expression of COX-2, MIB-1, p16 and EGFR was determined using tissue-array. Each PET was performed 60 minutes after the i.v. administration of 350-518 MBq of FDG on an Advance system (GE) in 2D acquisition mode.

RESULTS

COX-2 expression was detected in 35 out of 45 cases, and was very significant (> ++) in 12 of them. SUV values were lower in the COX-2 > ++ cases that in the remaining cases (13.4 +/- 1.2 vs. 12.9 vs. 17.1 +/- 1.5; p = 0.059). COX-2 > ++ expression and maxSUV values were not correlated with the clinical stage. The expression of COX-2 > ++ was correlated positively with p16 (r = 0.36; p = 0.014) and negatively with MIB1 (r = -0.32; p = 0.041) expression, whereas the SUV was correlated positively with EGFR (r = 0.44; p = 0.004) and negatively with p16 (r = -0.29; p = 0.041) expression.

CONCLUSIONS

Our results suggest that: a) the expression of COX-2 > ++ is often found in this kind of lung cancer and is not associated with the clinical stage; b) the maxSUVs were not related to the stage and were lower in COX-2 > ++ tumours than in the other cases; and c) the different behaviour of both parameters can be explained by their correlation with cell proliferation (MIB1), EGFR and p16 expression.