Evaluation of p16(INK4a) Immunohistochemical Reactivity in Endocervical Glandular Neoplasia

Objective. To determine the expression of p16(INK4a) by immunohistochemistry in endocervical neoplasms. Methods. Forty-nine cases of endocervical glandular neoplasia were identified by record review. On histopathologic review of the original and new slides, 16 cases were identified as endocervical adenocarcinoma in situ (AIS), 31 were identified as invasive adenocarcinoma, and 2 had no remaining tumor identified. A representative paraffin block was selected from each case with tumor and sections cut from each block. One section from each case was stained with hematoxylin and eosin, 1 was processed for immunohistochemical study for p16(INK4a), and 1 was a negative control. The nuclear immunoreactivity was graded positive, indeterminate, or negative. Results. Cases were classified AIS, adenocarcinoma, or no tumor. Of 16 cases of AIS, 15 (93.01%) cases were immunoreactive to p16(INK4a); 1 case was negative. All cases of invasive adenocarcinoma, 31 of 31 cases (100%), were immunoreactive to p16(INK4a). Conclusions. p16(INK4a) reactivity can be used to help identify and assess in situ and invasive endocervical glandular neoplasms