Immunostaining for p16INK4a Used as a Conjunctive Tool Improves Interobserver Agreement of the Histologic Diagnosis of Cervical Intraepithelial Neoplasia

Abstract

The quality of cervical histopathology is critical to cervical cancer prevention, cancer treatment, and research programs. On the basis of the histology results further patient management is determined. However, the diagnostic interpretation of histologic hematoxylin-eosin (H&E)-stained slides is affected by substantial rates of discordance among pathologists. Overexpression of the cyclin-dependent kinase inhibitor p16INK4a, a cell cycle regulating protein, has been shown to be strongly correlated with dysplastic lesions of the cervix uteri. In this study, we assessed whether p16INK4a immunohistochemistry may increase the performance of pathologists in diagnosing squamous lesions in cervical punch and cone biopsies. When using a consecutive p16INK4a-stained slide in conjunction to the H&E-stained slide, interobserver agreement between 6 pathologists improved significantly for both cervical punch and cone biopsies (P < 0.001). For punch biopsies (n = 247), kappa value increased from 0.49 (moderate agreement) to 0.64 indicating substantial agreement, and interobserver agreement for cone biopsies (n = 249) improved from 0.63 (conventional H&E slide reading) to 0.70 when H&E-stained slides were read conjunctively with p16INK4a-stained slides. In comparison to a common consensus diagnosis established by 3 independent experts, 4 pathologists reached an improvement with the conjunctive p16INK4a test, 2 of them showing significantly better agreement (P < 0.001 and P = 0.002, respectively), p16INK4a immunohistochemistry as an adjunct to conventional H&E-stained specimens thus contributes to a more reproducible diagnosis of cervical intraepithelial neoplasia and may be a valuable aid for the interpretation of cervical histology.

The Lower Anogenital Squamous Terminology Standardization Project for HPV-Associated Lesions: Background and Consensus Recommendations from the College of American Pathologists and the American Society for Colposcopy and Cervical Pathology

“…Additional studies have demonstrated a strong positive correlation between p16 block staining and precancerous disease [89,[164][165][166][167][168]. p16 immunostaining substantially reduces interobserver variability in the diagnosis of precancerous disease (see next paragraphs) [88][89][90][91]163]. Studies also show that diffuse strong p16 staining is highly associated with a positive test result for HPV-16 (or other high-risk HPVs) [169][170][171].…”

“…Further methods for more precise classification of identified lesions using biomarkers are discussed in the recommendations from WG4. There is evidence to show that using certain biomarkers significantly increases interobserver agreement [88][89][90][91].…”

“…3.-A number of studies address the issue of interobserver variability in interpretation of LAT squamous lesions [88][89][90][91]163]. These studies all show that there is substantial improvement in Figure 19.…”

Evaluation of cervical cone biopsies for coexpression of p16INK4a and Ki‐67 in epithelial cells

“…Its use in conjunction with hematoxylin and eosin (H&E)-stained sections has substantially improved the interobserver agreement and diagnostic accuracy in the histopathologic evaluation of cervical biopsies. [8][9][10] Furthermore, there is evidence that detection of p16…”

Polish recommendations regarding diagnostics and treatment of cervical squamous intraepithelial lesions according to the CAP/ASCCP guidelines

“…Genotypes of HPV were assigned into two groups depending on the risk for malignant transformation. The HPV subtypes of low oncogenic potential: 6 …”