Immunoexpression of cyclooxygenase-2 and p53 in oral squamous cell carcinoma.
OBJECTIVE
Cyclooxygenase-2 (COX-2) is an induced proinflammatory enzyme involved in various steps of carcinogenesis such as cell proliferation, reduction in apoptosis rates, and promotion of tumor angiogenesis. Mutation or inactivation of the tumor suppressor gene p53 is frequently observed in malignant neoplasms and is known to be involved in the early stages of carcinogenesis. Recent studies reveal a possible correlation between COX-2 and p53 expression in several malignant neoplasms. The present study analyzed the correlation between the expression of COX-2 and p53 in oral squamous cell carcinoma (OSCC) and evaluated the differences in the expression of these 2 proteins according to the histologic grade of malignancy of the tumor.


METHODS
Thirty-four cases of OSCC were graded according to the histologic grading system proposed by Bryne [Oral Dis 4(2) (1998) 70-77]. Immunoexpression of COX-2 and p53 was analyzed by counting 1000 neoplastic cells in 5 different fields at the deep invasive front of the tumor under a light microscope. On the basis of the number of immunopositive cells, the labeling index expressed as the percentage of positively stained cells was established for each marker.


RESULTS
Increased COX-2 expression in most specimens was observed, although no significant correlation was observed between COX-2 and p53 labeling indices (P > .05). Moreover, there were no significant differences in the expression of these proteins between high- and low-grade tumors (P > .05).


CONCLUSIONS
The increased expression of COX-2 in OSCC suggests a role for this protein in the pathogenesis and progression of oral cancer.
Goulart Filho
João Augusto Vianna
JA
Postgraduate Program in Oral Pathology, Federal University of Rio Grande do Norte, RN, Brazil.
Nonaka
Cassiano Francisco Weege
CF
da Costa Miguel
Márcia Cristina
MC
de Almeida Freitas
Roseana
R
Galvão
Hébel Cavalcanti
HC
D015415:Biomarkers / Q000378:metabolism; D002294:Carcinoma, Squamous Cell / Q000378:metabolism* / Q000473:pathology* / Q000601:surgery; D051546:Cyclooxygenase 2 / Q000378:metabolism*; D006801:Humans; D009062:Mouth Neoplasms / Q000378:metabolism* / Q000473:pathology* / Q000601:surgery; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D012307:Risk Factors; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
D015415:Biomarkers; D016159:Tumor Suppressor Protein p53; D051546:Cyclooxygenase 2