Immunocytochemistry of p16^INK4ain liquid-based cervicovaginal specimens with modified Papanicolaou counterstaining

Abstract

INK4a and conventionally counterstained with haematoxylin. The intensity of immunostaining in cases of squamous intraepithelial lesion (SIL) was assessed using a 0-3 scoring system. Interobserver agreement was calculated by k statistics. Results: Expression of p16INK4a was detected in 3 of 23 cases of WNL, 4 of 6 cases of LSIL, all cases of HSIL, 5 of 16 cases of ASC-US and 13 of 16 cases of ASC-H. Excluding two cases with no residual dysplastic cells in the immunocytochemistry, all cases of cervical intraepithelial neoplasia (CIN)2 or CIN3 at follow-up expressed p16INK4a and none of the p16 INK4a -negative cases showed a high-grade lesion at follow-up. No evident differences in pattern or intensity of p16INK4a expression were observed between the specimens of the study and control groups. Interobserver agreement was significantly better in the study group than in the group with conventional immunostaining (combined k 0.773 v 0.549; p,0.05), and still better, albeit statistically not significant, than with conventional immunostaining and cervical smear test together (combined k 0.773 v 0.642). Conclusion: Immunocytochemistry with p16INK4a and modified Papanicolaou counterstain may add to the cervicovaginal cytology the full potentiality of p16INK4a without the need of a further slide and the risk of loss of dysplastic cells, yet maintaining the typical morphological features of the smear test.

p16INK4a immunocytochemistry in liquid-based cervical cytology: is it feasible for clinical use?

“…We can also evaluate the nature of immunoreactive cells by counterstaining with Papanicolaou. This is supported by another study (22), confirming our notion that transformed keratinocytes stain in the nucleus, as opposed to cytoplasmatic staining seen in metaplastic and glandular cells in inflammatory conditions, unrelated to a precancerous process. Wentzensen et al have approached the difficulty of staining interpretation by proposing a nuclear scoring system to identify transformed cells (19,23).…”

Antibody Anti-p16INK4a in Cervical Cytology

“…Considering the maximum positivity of 18% found among individuals without lesion, 32 the minimum positivity of 60% found among cases of CIN 1 47 and the minimum positivity of 80% found among cases of CIN 2 or 3, 33 the use of the statistical software package PEPI version 4.0 (Computer Programs for Epidemiologists, Sagebrush Press, Salt Lake City, Utah, U.S.A.) resulted in a minimum sample size of 31 cases of CIN 1, 15 cases of CIN 2 or 3 and 46 controls. The parameters used were 95% α, 10% β (90% study power) with 1:1 control to case ratio.…”

Role of p16INK4a Cytology Testing as an Adjunct to Enhance the Diagnostic Specificity and Accuracy in Human Papillomavirus-Positive Women within an Organized Cervical Cancer Screening Program

“…The immunocytochemical reaction was considered positive if at least one atypical stained cell was contained within the previously marked areas or if there were evident cytopathological atypias in conjunction with nuclear, cytoplasmic or nucleocytoplasmic p16 staining, even if outside the marked fields [25]. Papanicolaou restaining of immunocytochemically stained slides permits an easier global reevaluation of the slides compared to Harris Hematoxylin counterstain, because the overall features of the cytological slides are maintained in this way [24] (fig. 2, 3, 4).…”

“…The immunocytochemical staining was performed using an automated immunostainer (i6000 by Genomix). The slides were contrasted by the Papanicolaou stain [24] after the immunocytochemical staining.…”