title: Interobserver reproducibility of cytologic p16INK4a/Ki-67 dual immunostaining in human papillomavirus-positive women.
abstract: BACKGROUND
  The accumulation of cyclin-dependent kinase inhibitor 2A (p16ink4a) protein in a cell is associated with neoplastic progression in precancerous cervical lesions. Dual staining for p16ink4aand Ki-67 has been proposed as a triage test in cervical cancer screening for women who test positive for human papillomavirus DNA. In this study, interobserver reproducibility of the interpretation of this test was assessed.
  
  
  METHODS
  Forty-two immunostained, liquid-based cytology slides were divided into 2 sets and were interpreted by 17 to 21 readers from 9 different laboratories, yielding a total of 816 reports. Immunostaining results were classified as positive, negative, inconclusive, or inadequate. After evaluation of the first set of slides and before circulation of the second set, the results were discussed in a plenary meeting. The 10 slides with the most discordant results were evaluated again by selected expert cytopathologists.
  
  
  RESULTS
  The overall κ value was 0.612 (95% confidence interval [CI], 0.523-0.701), it was higher for the positive and negative categories (κ = 0.692 and κ = 0.641, respectively), and it was almost null for the inconclusive category (κ = 0.058). Considering only readers from laboratories with documented experience, the κ value was higher (κ = 0.747; 95% CI, 0.643-0.839) compared with nonexperienced centers (κ = 0.498; 95% CI, 0.388-0.616). The results were similar in both sets of slides (κ = 0.505 [95% CI, 0.358-0.642] and κ = 0.521 [95% CI, 0.240-0.698] for the first and second sets, respectively). Reinterpretation of the slides with the most discordant results did not provide any improvement (first evaluation, κ = 0.616 [95% CI, 0.384-0.866]; second evaluation, κ = 0.403 [95% CI, 0.182-0.643]).
  
  
  CONCLUSIONS
  Dual staining for p16ink4aand Ki-67 demonstrated good reproducibility, confirming its robustness, which is a necessary prerequisite for its adoption as a triage test in cervical cancer screening programs that use human papillomavirus DNA as a primary test. Cancer Cytopathol 2017;125:212-220. © 2016 American Cancer Society.
authors.affiliation: Regina Elena National Cancer Institute, Rome, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Benevolo
authors.affiliation: Central Cervicovaginal Screening Unit and Center for Cancer Epidemiology and Prevention, Turin, Italy.
authors.forename: Elena
authors.identifier: http://orcid.org/0000-0002-4448-0443
authors.initials: E
authors.lastname: Allia
authors.affiliation: Laboratory Screening Unit, Local Health Authority-Umbria 1, Perugia, Italy.
authors.forename: Daniela
authors.initials: D
authors.lastname: Gustinucci
authors.affiliation: Regina Elena National Cancer Institute, Rome, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Rollo
authors.affiliation: Laboratory Screening Unit, Local Health Authority-Umbria 1, Perugia, Italy.
authors.forename: Simonetta
authors.initials: S
authors.lastname: Bulletti
authors.affiliation: Laboratory Screening Unit, Local Health Authority-Umbria 1, Perugia, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Cesarini
authors.affiliation: Laboratory Screening Unit, Local Health Authority-Umbria 1, Perugia, Italy.
authors.forename: Basilio
authors.initials: B
authors.lastname: Passamonti
authors.affiliation: Cytopathology Unit, St Andrea Hospital, "Sapienza" University, Rome, Italy.
authors.forename: Maria Rosaria
authors.initials: MR
authors.lastname: Giovagnoli
authors.affiliation: Cytopathology Unit, St Andrea Hospital, "Sapienza" University, Rome, Italy.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Carico
authors.affiliation: Human Papillomavirus Laboratory and Molecular Oncology Unit, Regional Cancer Prevention Laboratory, Institute for Cancer Study and Prevention, Florence, Italy.
authors.forename: Francesca M
authors.initials: FM
authors.lastname: Carozzi
authors.affiliation: Human Papillomavirus Laboratory and Molecular Oncology Unit, Regional Cancer Prevention Laboratory, Institute for Cancer Study and Prevention, Florence, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Mongia
authors.affiliation: Human Papillomavirus Laboratory and Molecular Oncology Unit, Regional Cancer Prevention Laboratory, Institute for Cancer Study and Prevention, Florence, Italy.
authors.forename: Giulia
authors.initials: G
authors.lastname: Fantacci
authors.affiliation: Human Papillomavirus Laboratory and Molecular Oncology Unit, Regional Cancer Prevention Laboratory, Institute for Cancer Study and Prevention, Florence, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Confortini
authors.affiliation: Institute for Research and Health Care (IRCCS), "Arcispedale S. Maria Nuova" Hospital, Reggio Emilia, Italy.
authors.forename: Teresa
authors.initials: T
authors.lastname: Rubino
authors.affiliation: Institute for Research and Health Care (IRCCS), "Arcispedale S. Maria Nuova" Hospital, Reggio Emilia, Italy.
authors.forename: Cristina
authors.initials: C
authors.lastname: Fodero
authors.affiliation: Institute for Research and Health Care (IRCCS), "Arcispedale S. Maria Nuova" Hospital, Reggio Emilia, Italy.
authors.forename: Sonia
authors.initials: S
authors.lastname: Prandi
authors.affiliation: Unit 17, Local Health and Social Care Facility, Este Monselice, Italy.
authors.forename: Natalina
authors.initials: N
authors.lastname: Marchi
authors.affiliation: Unit 17, Local Health and Social Care Facility, Este Monselice, Italy.
authors.forename: Angelo
authors.initials: A
authors.lastname: Farruggio
authors.affiliation: Central Cervicovaginal Screening Unit and Center for Cancer Epidemiology and Prevention, Turin, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Coccia
authors.affiliation: Central Cervicovaginal Screening Unit and Center for Cancer Epidemiology and Prevention, Turin, Italy.
authors.forename: Luigia
authors.initials: L
authors.lastname: Macrì
authors.affiliation: Central Cervicovaginal Screening Unit and Center for Cancer Epidemiology and Prevention, Turin, Italy.
authors.forename: Bruno
authors.initials: B
authors.lastname: Ghiringhello
authors.affiliation: Central Cervicovaginal Screening Unit and Center for Cancer Epidemiology and Prevention, Turin, Italy.
authors.forename: Guglielmo
authors.initials: G
authors.lastname: Ronco
authors.affiliation: Provincial Health Care Service, Trento, Italy.
authors.forename: Emma
authors.initials: E
authors.lastname: Bragantini
authors.affiliation: Provincial Health Care Service, Trento, Italy.
authors.forename: Enzo
authors.initials: E
authors.lastname: Polla
authors.affiliation: Department of Pathology, Avezzano, Sulmona, and L'Aquila Local Health Trust-Abruzzo, Avezzano, Italy.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Maccallini
authors.affiliation: Department of Pathology, Bolzano Central Hospital, Bolzano, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Negri
authors.affiliation: Institute for Research and Health Care (IRCCS), "Arcispedale S. Maria Nuova" Hospital, Reggio Emilia, Italy.|Interinstitutional Epidemiology Unit, Reggio Emilia Local Health Trust, Reggio Emilia, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Giorgi Rossi
mesh_terms: D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000032:analysis*; D005260:Female; D006801:Humans; D019394:Ki-67 Antigen / Q000032:analysis*; D015588:Observer Variation; D030361:Papillomavirus Infections / Q000175:diagnosis*; D011230:Precancerous Conditions / Q000175:diagnosis*; D015203:Reproducibility of Results; D002583:Uterine Cervical Neoplasms / Q000175:diagnosis*
chemical_list: D019941:Cyclin-Dependent Kinase Inhibitor p16; D019394:Ki-67 Antigen
keywords: cervical cancer; cyclin-dependent kinase inhibitor 2A (p16ink4a)/Ki-67; dual immunostaining; human papillomavirus; inter-rater agreement