Utility of p16(ink4a) immunocytochemistry in liquid-based cytology specimens from women treated for high-grade squamous intraepithelial lesions.
OBJECTIVE
To examine whether p16(ink4a) immunocytochemical (ICC) expression detected intraepithelial disease in liquid-based cytology (LBC) specimens from women with high-grade squamous intraepithelial lesions (HSIL), whose specimen was labeled negative for intraepithelial lesion or malignany (NILM).


METHODS
Residual LBC specimens from women treated for HSIL (n = 21), whose LBC test was interpreted as NILM including marked benign inflammatory changes (BCC) were used. The control (n = 25) consisted of residual LBC specimens from women with documented HSIL. ICC for p16p(16k4a) was performed on a second ThinPrep (ThinPrep 2000, Cylyl Corporation, Boxborough, Massachusetts, U.S.A.) preparation; the percentage ofpositive cells and intensity of immunostaining were recorded. Standard LBC preparations for p16(ink4a) ICC-positive and ICC-negative control cases were reviewed.


RESULTS
Twenty-four of 25 (96%) of the HSIL control group were ICC p16(ink4a) positive. In the NILM/BCC group, 2 of 21 with adequate LBC residua were ICC p16(ink4a) positive; on review both were reclassified as epithelial abnormality--1 HSIL and 1 atypical squamous cells cannot exclude HSIL. In both, subsequent colposcopic biopsy yielded HSIL.


CONCLUSIONS
p16(ink4a) ICC positivity on NILM/BCC LBC residua from patients with HSIL may identify cases that merit cytologic review and possible reclassification. The utility of p16(ink4a) ICC in this situation requires further study.
Carydis
Vasiliki Bessie
VB
Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, Ontario, Canada. bcarydis@mtsinai.on.ca
Walker
Todd
T
Wing
Anthony
A
Colgan
Terence J
TJ
D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000378:metabolism*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D018307:Neoplasms, Squamous Cell / Q000378:metabolism* / Q000473:pathology; D002583:Uterine Cervical Neoplasms / Q000378:metabolism* / Q000473:pathology; D014626:Vaginal Smears; D002578:Uterine Cervical Dysplasia / Q000378:metabolism* / Q000473:pathology
D019941:Cyclin-Dependent Kinase Inhibitor p16