Immunohistochemical Expression of the Tumor Suppressor Protein p16 ^INK4a in Cervical Adenocarcinoma

Expressão imunhistoquímica da proteína de supressão tumoral p16 ^INK4a em adenocarcinoma cervical

ABSTRACT

Objective:

To evaluate the diagnostic utility of the p16^ink4a protein expression as a marker for adenocarcinoma of the cervix.

Methods:

In a cross-sectional study, p16^ink4a expression was evaluated in 30 cervical biopsies from patients diagnosed with invasive adenocarcinoma from 2 reference clinics in Brazil, and compared with 18 biopsies of endocervical polyps (control cases). The performance of the tests for p16^ink4a was evaluated using a conventional contingency table, and the Kappa (k) index was used to evaluate the agreement of the marker with the tissue diagnosis.

Results:

In total, 66% of the invasive adenocarcinoma cases were positive for p16^ink4a. All of the adenomatous polyps cases used as negative controls were shown to be negative for p16^ink4a. The marker showed a high sensitivity and a high negative predictive value. The Kappa index was good for p16^ink4a (k 1/4 0.6).

Conclusion:

Considering the strong association between the p16^ink4a marker and the cervical adenocarcinoma, its use represents an important tool for reducing incorrect diagnoses of adenocarcinoma and thereby avoiding overtreatment.

Keywords:
16^INK4a; adenocarcinoma; cervix; immunohisto-chemistry