Cyclo-oxygenase-2 (Cox-2) expression and resistance to platinum versus platinum/paclitaxel containing chemotherapy in advanced ovarian cancer.
BACKGROUND
Cyclo-oxygenase-2 (COX-2), the key enzyme in the conversion of arachidonic acid to prostaglandins, is involved in critical steps of tumor onset and progression, and is a strong predictor of chemotherapy resistance and poor outcome in advanced ovarian cancer. To our knowledge, no data has been reported until now about the association between COX-2 status and response to different chemotherapy regimens.


METHODS
A retrospective study was performed to investigate the association of COX-2 with outcome and response to platinum versus platinum/paclitaxel in 68 primary ovarian cancer. COX-2 immunoreaction was performed on paraffin-embedded sections by using rabbit polyclonal antiserum against COX-2.


RESULTS
In the overall series, COX-2 positivity was found in a statistically significant higher percentage of not responding cases than in patients responding to chemotherapy (n = 15/21; 71.4% versus n = 17/47; 36.1%; p value = 0.0072). A higher percentage of COX-2 positivity was found in patients unresponsive (n = 11/13; 84.6%) versus patients responsive to platinum-based chemotherapy (n = 9/26; 34.6%). In cases administered platinum/paclitaxel, COX-2 positivity was found in 4 out of 8 (50%) of un responsive versus 8 out of 21 (38.1%) of responsive cases. Logistic regression analysis of parameters likely to affect response to treatment resulted in a p value = 0.17 for the interaction COX-2/type of treatment.


CONCLUSIONS
Although these findings need to be confirmed in a larger series, our study suggests a possible indication that there is a difference in the influence of COX-2 on response depending on treatment regimen.
Ferrandina
Gabriella
G
Gynecologic Oncology Unit, Catholic University, L,go Gemelli 8, 00168, Rome, Italy. gabriella.ferrandina@libero.it
Ranelletti
Franco O
FO
Martinelli
Enrica
E
Paglia
Amelia
A
Zannoni
Gian Franco
GF
Scambia
Giovanni
G
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D051546:Cyclooxygenase 2 / Q000378:metabolism*; D018450:Disease Progression; D019008:Drug Resistance, Neoplasm; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D008875:Middle Aged; D009367:Neoplasm Staging; D010051:Ovarian Neoplasms / Q000188:drug therapy* / Q000201:enzymology* / Q000473:pathology; D017239:Paclitaxel / Q000627:therapeutic use*; D010984:Platinum / Q000627:therapeutic use*; D015996:Survival Rate
D010984:Platinum; D051546:Cyclooxygenase 2; D017239:Paclitaxel