title: Immunocytochemical colocalization of P16(INK4a) and Ki-67 predicts CIN2/3 and AIS/adenocarcinoma.
abstract: BACKGROUND
  Although previous studies have shown that p16(INK4a) and Ki-67 are sensitive and specific markers for high-grade lesions (≥CIN2) on cervical biopsies, limited information is available regarding the performance of a dual-staining approach as a diagnostic adjunct in cervical cytology. We evaluated a dual p16(INK4a)/Ki-67 immunocytochemistry (ICC) assay to determine its sensitivity and specificity versus that of high-risk HPV (HR-HPV) in a US-based pilot cytology study.
  
  
  METHODS
  ThinPrep specimens from 122 cervical cytology specimens encompassing 23 negative (NILM), 20 ASC-US, 22 LSIL, 17 ASCH, 22 HSIL, and 18AGC cases were processed for multiplexed ICC staining using a CINtec Plus Kit. Dual-positive assay results were defined based on the detection of 1 or more epithelial cells that were stained for both p16INK4a and Ki-67 without regard to cellular morphology. HR-HPV testing was performed by multiplex PCR with capillary electrophoresis genotyping.
  
  
  RESULTS
  Dual staining for p16(INK4a) and Ki-67 was frequently detected in HSIL and AGC but was rarely detected in NILM cases. The HR-HPV assay showed a sensitivity of 76.2% and a specificity of 55.8% for the detection of clinically significant cervical squamous or endometrial lesions. In contrast, the colocalization of p16(INK4a) plus Ki-67 maintained a high sensitivity of 81.8% and improved specificity to 81.8% for biopsy-confirmed CIN2/3, endocervical adenocarcinoma, or endometrial adenocarcinoma.
  
  
  CONCLUSIONS
  Dual staining for p16(INK4a)/Ki-67 immunocytochemistry dramatically increased specificity and maintained high-level sensitivity for the diagnosis of CIN2/3 or glandular lesions compared with PCR-based testing for HR-HPV.
authors.affiliation: State University of New York at Stony Brook, Stony Brook, New York, USA.
authors.forename: Meenakshi
authors.initials: M
authors.lastname: Singh
authors.forename: Daniel
authors.initials: D
authors.lastname: Mockler
authors.forename: Ali
authors.initials: A
authors.lastname: Akalin
authors.forename: Stephanie
authors.initials: S
authors.lastname: Burke
authors.forename: A  Laurie
authors.initials: A
authors.lastname: Shroyer
authors.forename: Kenneth R
authors.initials: KR
authors.lastname: Shroyer
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis*; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000032:analysis*; D003581:Cytodiagnosis; D055088:Early Detection of Cancer / Q000379:methods; D005260:Female; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods*; D019394:Ki-67 Antigen / Q000032:analysis*; D060885:Multiplex Polymerase Chain Reaction; D030361:Papillomavirus Infections / Q000175:diagnosis; D010865:Pilot Projects; D012680:Sensitivity and Specificity; D002583:Uterine Cervical Neoplasms / Q000175:diagnosis* / Q000821:virology; D002578:Uterine Cervical Dysplasia / Q000175:diagnosis*
chemical_list: D019941:Cyclin-Dependent Kinase Inhibitor p16; D019394:Ki-67 Antigen