Immunocytochemical staining of p16^INK4a protein from conventional Pap test and its association with human papillomavirus infection

Abstract

The p16INK4a protein is immunocytochemically detected in liquid-based (LB) specimens as a diagnostic marker of cervical dysplasia and neoplasia. Its up-regulation is promoted by high-risk human papillomavirus (HR-HPV) infection. We aimed to detect p16INK4a on conventional Papanicolaou (Pap) test (CPT) slides and to determine the relationship between its overexpression and HR-HPV infection. CPT and LB Pap test (LBPT) slides (165 samples of each) were examined by immunocytochemical staining for p16INK4a. After polymerase chain reaction (PCR), HPV-DNA was genotyped by dot blot hybridization. The CPT slides displayed more numerous dispersed squamous cells and LBPT slides had a clearer background. Positive p16INK4a on CPT occurred in 0% (0/30), 52.5% (21/40), 54.3% (19/35), 100% (30/30), and 100% (30/30) in normal, atypical squamous cells of undetermined significance (ASCUS), low-grade squamous intraepithelial lesions (LSILs), high-grade SILs (HSILs), and squamous cell carcinomas (SCCs) cases, respectively. LBPT slides showed comparable results but were less sensitive. HPV-DNA was detected in 86.7, 70, 45, 57.14, and 10% in SCCs, HSILs, ASCUS, LSILs, and normal cervical cells, respectively. Because HR-HPV was identified in all HPV+ samples of high-grade dysplasia (HSILs and SCCs) and all positive p16INK4a samples infected with HR-HPV, the association of p16INK4a overexpression with HR-HPV infection was confirmed. This study suggests that immunocytochemical staining of p16INK4a on CPT slides is convenient and cost-effective for cervical cancer screening by the detection of dysplastic cells infected with HR-HPV.

Antibody Anti-p16INK4a in Cervical Cytology

“…Such results reproduce the findings of the literature in the antibody proposed. [32][33][34]47 On precursory cervical lesions, when examined together (CIN 1, 2 or 3), the study reproduces literature findings with sensitivity ranging from 75.4% 34 to 92.3%. 47 For CIN 1, sensitivity of the diagnostic test was 77.8% and 58.3% between P1 and P2, respectively, partially following the literature findings, in which there is a variation from 54.3% 34 to 74.1%.…”

Utility of p16ink4a Immunocytochemistry in Liquid-Based Cytology Specimens from Women Treated for High-Grade Squamous Intraepithelial Lesions

“…In the current study we demonstrated a 96% (24 of 25 cases) overexpression of p16 ink4a protein in known HSIL cases in the control group (Table I), similar to results reported by Pientong et al 20 The single HSIL case lacking ICC positivity was reclassified as NILM on microscopic review. Our findings also concur with (24) < 10% (3) Weak (3) > 10% < 50% (18) Strong (12) Weak (6) > 50% (3) Strong (3) Study group (21) NILM (19) None None HSIL/ASC-H (2) < 10% (1) Weak (1) > 10% < 50% (1) Strong (1) Figure 2 Immunocytochemical stain for p16 ink4a of a cell cluster from the study cohort.…”

“…1,4,[6][7][8][9][13][14][15][16][17][18][20][21][22]24 Furthermore, the ICC demonstration of p16 ink4a overexpression is simple and reproducible and suitable to a variety of preparation methods; including histologic sections, cytologic cell blocks, conventional Papanicolaou smears and LBC of ThinPrep and SurePath (SurePath Medical Industries, Richmond, Illinois, U.S.A.) types. 1,4,6-9,12-18, [20][21][22]24 This study sought to identify the utility of ICC staining for p16 ink4a in a specific clinical laboratory situation. The study group was well defined and corresponded to a common and meaningful clinical challenge-the identification of persistent HSIL post treatment.…”

Comparison of p16INK4a and ProEx™ C immunostaining on cervical ThinPrep® cytology and biopsy specimens

“…A study by Duncan et al 2 recently reported p16 staining of benign atrophic squamous cells in 88% of atrophic specimens. Other authors have identified p16 staining in tubal metaplasia, [16][17][18] benign endometrial cells, 16,18,19 and trichomonas. 20 Benevolo et al 1 suggested that p16 staining of cervical ThinPrep cytology specimens offered no additional benefit to currently used strategies (conventional morphology with HPV testing).…”