Inverse modulation of intraepithelial Langerhans' cells and stromal macrophage/dendrocyte populations in human papillomavirus-associated squamous intraepithelial lesions of the cervix

Ninety-four cervical biopsies from normal tissue to high-grade squamous intraepithelial lesion (SILs) were examined for the presence of intraepithelial Langerhans' cells and subpopulations of stromal macrophages/dendrocytes by immunohistochemistry using anti-S100,-L1, -CD68 and -factor XIIIa antibodies. Human papillomavirus (HPV) detection was performed in all cases by using first a mixture of DNA probes for 14 HPV types commonly found in anogenital biopsies at low stringency conditions (T _m -40°C) and by reanalyzing the tissues at high stringency (T _m - 10°C) with HPV 6/11, 16/18 and 31/33/35 biotinylated probe cocktails and individual digoxigenin-labelled probes. SILs and metaplastic tissues were significantly associated with a depletion of S100-positive intraepithelial Langerhans' cells when compared with normal epithelium. In contrast, there was a significant increase in L1-positive stromal macrophages in SIL biopsies compared with normal or metaplastic cervix. A significantly higher density of CD68-positive macrophages was also observed in high-grade SILs compared with normal or metaplastic biopsies and with low-grade SILs. The density of factor XIIIa-positive dendrocytes was found to be higher in SILs compared with metaplastic tissues and in high-grade SILs when compared with normal cervical biopsies. No specific relationship was found between the densities of these cells and the HPV type detected in SILs separated into low grade and high grade. The significance of this inverse modulation of intraepithelial Langerhans' cells and stromal macrophages/dendrocytes in normal and SIL biopsies is discussed in relation to HPV infection and malignant transformation.     

Changing Roles of Cadherins and Catenins during Progression of Squamous Intraepithelial Lesions in the Uterine Cervix

Uterine cervix represents a convenient model for the study of the gradual transformation of normal squamous epithelium via low- to high-grade squamous intraepithelial lesions (SILs). Because SIL, on the basis of the cytokeratins expressed, are thought to originate from the reserve cells, we analyzed whether SILs also show a reserve cell phenotype with respect to intercellular interactions. The changes in expression and subcellular localization of the components of the adherens junction and desmosomal complexes were investigated in normal, metaplastic, and premalignant cervical epithelium, as well as in cell cultures derived from these tissues. The results suggest that 1) during progression of SILs, E-cadherin is suppressed, with its role in cell-cell connections diminishing; 2) P-cadherin, in contrast, becomes the predominant cadherin in high-grade SILs; 3) the level of cellular alpha-catenin is dramatically decreased in high-grade SILs; 4) the level of beta-catenin is decreased during progression of SILs, with plakoglobin suggestively becoming the predominant catenin mediating connection of cadherins to the cytoskeleton; 5) the assembly of desmosomes is affected during progression of SILs and is accompanied by a dramatically decreased expression for desmogleins and desmoplakins (I, II); and 6) expression of differentiation markers (involucrin, CK13) in high-grade SILs seems to be controlled by P-cadherin as opposed to E-cadherin in the normal tissue counterpart. We conclude that during development of cervical lesions substantial (both quantitative and qualitative) changes occur in cell-cell junctions, making the interactions of cells in lesions dissimilar from those of reserve cells, basal cells, or cells of immature squamous metaplasia, despite existing morphological similarity between all of these cell types and cells of high-grade lesions.     

Distinct T cell subsets and cytokine production in cultures derived from transformation zone and squamous intraepithelial lesion biopsies of the uterine cervix

PROBLEM: The characterization of lymphocytes issued from squamous intraepithelial lesions (SIL) and from the transformation zone (TZ), where the majority of SIL occur, is important to understand the role of immunity in SIL development. METHOD OF STUDY: We compared lymphocyte populations of the TZ and SIL with those of normal exocervix, using a technique allowing for the isolation of lymphocytes, either from the epithelium or from the underlying stroma of small biopsies. RESULTS: The majority of cells derived from the epithelium of all biopsies were CD8+ T cells. Some SIL-derived cultures were characterized by an increased proportion of activated TCRgammadelta+. The production of the immunosuppressive cytokine IL10 was significantly higher in lymphocyte cultures from the normal TZ in comparison with the exocervix. A decreased percentage of effector T cells was observed in cultures derived from the stroma of normal TZ (TCRgammadelta+) or SIL (CD8+) in comparison with the exocervix. CONCLUSIONS: Our results suggest that a low proportion of effector T cells and IL10 production could contribute to the predisposition of the TZ to the development of SIL and to the progression of SIL to cervical cancer.     

Noncorrelating Pap tests and cervical biopsies: histological predictors of subsequent correlation

Lack of correlation between dysplastic cervicovaginal Papanicolaou (Pap) tests and subsequent cervical biopsies raises the concern that a significant squamous intraepithelial lesion (SIL) may go unconfirmed. Additional tissue sections of cervical biopsies may detect SILs after noncorrelation on initial sections. Complete step sectioning of paraffin blocks was undertaken on 111 noncorrelating biopsy specimens from 95 patients and selected slides were reviewed for the presence of SIL. The initial negative biopsy slides were evaluated for four histological features: chronic cervicitis, acute cervicitis, mucosal erosion, and squamous atypia. Twenty-seven biopsies (24.3%) demonstrated the presence of a SIL in deeper levels. The presence of squamous atypia was significantly associated with the presence of dysplasia deeper in the block (P < 0.002). Acute and chronic cervicitis was seen roughly equally. Additional tissue levels are a productive way of confirming SILs, and squamous atypia allows a refined selection of negative cervical biopsies most likely to reveal an SIL on review of deeper levels.     

Altered expression of desmosomal components in high-grade squamous intraepithelial lesions of the cervix

We have used immunohistochemistry to test the hypothesis that components of the desmosome are disrupted during neoplastic progression of squamous epithelial cells in the uterine cervix. Sections of normal cervix and squamous intraepithelial lesions (SILs) were immunostained for desmosomal proteins and glycoproteins, and results were assessed using a semi-quantitative grading system. No difference between normal cervix and low-grade SIL (LSIL) was found. A significant reduction in expression of desmogleins was seen between high-grade SIL (HSIL) and LSIL (P<0.01) and normal cervix (P<0.001). Desmocollin expression was not reduced significantly, although scores showed significantly greater variation in HSIL compared with LSIL (P<0.05) and normal cervix (P<0.05). There was no significant difference in desmoplakin expression among the three groups. The results suggest that there may be sequential disruption of desmosomal function during neoplastic progression of cervical squamous intraepithelial cells, with downregulation of desmogleins during the progression from LSIL to HSIL and loss of desmocollin expression occurring in some cases of established HSIL.     

E-cadherin-dependent adhesion of dendritic and Langerhans cells to keratinocytes is defective in cervical human papillomavirus-associated (pre)neoplastic lesions

Although human papillomavirus (HPV) DNA is detected in the majority of squamous intraepithelial lesions (SILs) and squamous cell carcinomas (SCCs) of the uterine cervix, the persistence and progression of cervical lesions suggest that viral antigens are not adequately presented to the immune system. This hypothesis is reinforced by the observation that most SILs show quantitative and functional alterations of Langerhans cells (LCs). The aim of this study was to determine whether modulation of E-cadherin-mediated homophilic and heterotypic interactions between keratinocytes and LCs is involved in these abnormalities of LCs in (pre)neoplastic cervical epithelium. Cell membrane expression of E-cadherin and the density of CD1a+ LCs were low in the epithelium of SILs and SCC biopsy specimens, compared with normal exocervical epithelium. Dendritic cells (DCs) and LCs generated in vitro were randomly distributed throughout the full thickness of organotypic cultures of E-cadherin- HPV-transformed cells. In contrast, these cells rapidly adhered to the keratinocyte cell layers when HPV-transformed cells transfected with E-cadherin were used. These data suggest that the E-cadherin-mediated contact between keratinocytes and LCs is potentially important for initiating or maintaining the immune response during chronic HPV infection.     

E-cadherin, CD44 and CD44v6 in squamous intraepithelial lesions and invasive carcinomas of the uterine cervix: an immunohistochemical study.

OBJECTIVE: To evaluate the immunoexpression pattern of E-cadherin, CD44std and the variant isoform v6 in normal squamous epithelium, low and high squamous intraepithelial lesions (SILs) and invasive squamous cell carcinomas (ISCCs) of the uterine cervix. The purpose was to determine whether any distinctive change in antigenic expression could contribute to the recognition of the earliest commitment to neoplasia and/or the onset of the invasive phenotype. METHODS: Immunohistochemistry using the avidin-biotin indirect immunoperoxidase method was used to study the protein expression of epithelial cadherin (E-cadherin), cluster differentiation 44 (CD44), and the isoform v6 (CD44v6) in 124 human cervical samples (5 normal, 39 low-grade, 54 high-grade and 26 ISCCS) in formalin-fixed, paraffin-embedded tissue blocks. RESULTS: Membranous expression of E-cadherin, CD44 and CD44v6 was preserved in normal squamous epithelium and in low-grade squamous intraepithelial lesions. A significant association was observed with the histological grade of the SILs and the immunoreactivity (membranous versus cytoplasmic) pattern of E-cadherin (p < 0.001), CD44std (p = 0.027) and CD44v6 (p < 0.001). A loss of membranous staining and a progressive increase in cytoplasmic staining was observed from low to high grade SILs to ISCCs. CONCLUSIONS: Our study demonstrates that during the development of cervical lesions substantial qualitative (subcellular localization-membrane to cytoplasmic) and quantitative alterations (changes in expression) occur in the protein expression of E-cadherin, CD44, and CD44v6 in cervical cancer. The most striking observation was the decrease in membranous immunoreactivity and the progressive increase in cytoplasmic staining of E-cadherin, CD44 and CD44v6, relating to loss of differentiation as a consequence of neoplastic transformation.     

p53 Immunoreactivity in inflammatory and neoplastic diseases of the uterine cervix

Immunoreactivity for the tumour suppressor gene product p53 is commonly found in many different human malignancies and few premalignant lesions. Data on cervical neoplasms, however, are still lacking. We retrospectively investigated p53 immunoreactivity in 92 lesions of the uterine cervix, including 44 cases of chronic cervicitis, 29 squamous intraepithelial lesions (SILs), and 19 invasive carcinomas. p53 immunoreactivity confined to the basal cell layer, was detected in 74 per cent of cases showing chronic cervicitis and in all cases with low-grade SILs. Conversely, suprabasal and/or diffuse p53 immunoreactivity was exclusively demonstrated in 25 per cent of high-grade SILs and in 74 per cent of invasive carcinomas. The results of this investigation document a high prevalence of p53-immunoreactive malignant tumours of the uterine cervix. In high-grade SILs, p53-immunoreactive cells paralleled the height of involvement by dysplastic changes within the squamous epithelium. A prolonged half-life of the protein is the most likely explanation for the occurrence of p53 immunoreactivity in neoplastic cells. The unexpected finding of p53-immunoreactive cells in inflammatory lesions, though possibly related to an increased proliferation rate of the basal cell compartment, requires further study and underlines the need for a careful approach to p53 immunocytochemistry.     

The antigen-presenting environment in normal and human papillomavirus (HPV)-related premalignant cervical epithelium

The activation of HPV-specific T cells within the cervical microenvironment is likely to play an important part in the natural history of cervical intraepithelial neoplasia (CIN). The extent and the type of T cell activation will depend critically on the expression of MHC, costimulatory cell surface molecules and cytokines by keratinocytes and Langerhans cells within the cervical lesion. Expression of MHC class II (HLA-A-DR and -DQ), costimulatory/adhesion molecules (CD11a/18, CD50, CD54, CD58 and CD86) and cytokines (tumour necrosis factor-alpha (TNF-alpha) and IL-10) was therefore investigated by immunohistochemistry in normal squamous epithelium (n = 12), low-grade (n = 23) and high-grade (n = 18) squamous intraepithelial lesions of the cervix. CIN progression was associated with de novo expression of HLA-DR and CD54, and increased expression of CD58 by keratinocytes. However, significantly, there was no expression of any adhesion/costimulation molecule by epithelial Langerhans cells in any cervical biopsy studied. Furthermore, TNF-alpha, a potent activator of Langerhans cells, was expressed constitutively by basal keratinocytes in normal cervix (12+/12). but expression of this cytokine was absent in a number of CIN samples (20+/23 for low-grade, 12+/18 for high-grade CIN). Conversely, the suppressive cytokine IL-10 was absent in normal epithelium (0+/12), but was up-regulated in a number of CIN lesions (12+/23 for low-grade; 8+/18 for high-grade CIN). The restricted expression of costimulation/adhesion molecules and the nature of the cytokine microenvironment within the epithelium may act to limit effective immune responses in some CIN lesions.     

Reporting of atypical squamous cells,cannot exclude a high‐grade squamous intraepithelial lesion (ASC‐H) on cervical samples: Is it significant?

"Atypical squamous cells, cannot exclude a high-grade squamous intraepithelial lesion (ASC-H)" is a new diagnostic category in the 2001 Bethesda nomenclature system for cervical cytology. The purpose of this 7-mo retrospective study (March 1, 2002-September 30, 2002) was to evaluate the significance of ASC-H on cervical Thin Prep Pap Tests. During this period, 25 (0.27%) of 9,214 Pap Tests were diagnosed as ASC-H, 22 of which resulted in either follow-up cervical biopsies and/or cervical cones, and which formed the basis of this study. Tissue specimens (22 cases) were negative in 5 cases (23%) and positive in 17 cases (77%). Of the positive specimens, there were 2 (12%) low-grade squamous intraepithelial lesions (LSIL) and 15 (88%) high-grade squamous intraepithelial lesions (HSIL). Of the 22 cases, ASC-H diagnoses included immature/atypical squamous metaplasia vs. a squamous intraepithelial lesion (SIL) in 19 (86%) cases, and tight clusters of small cells with a high nuclear to cytoplasmic ratio in 3 (14%) cases. The results of this study indicate that the reporting of ASC-H on cervical samples does lead to the detection of HSILs in a significant number of cases (68% in this study). Therefore, further evaluation of the patient is warranted.     

Extensively keratinized squamous intraepithelial lesions of the cervix are difficult to grade

We tested the hypothesis that extensively keratinized squamous intraepithelial lesions (SILs) are difficult to grade precisely by identifying 100 Papanicolaou smears with a keratinizing SIL that had been originally judged difficult to grade. Of these, 65 were confirmed as low-grade SIL (LSIL) or high-grade SIL (HSIL) on subsequent biopsy. The 65 smears were reviewed independently by 3 cytopathologists who graded each case as LSIL or HSIL (by Bethesda System criteria). The accuracy of the grade was determined by the subsequent biopsy results; accuracy was compared with that of a historic control group of SILs with biopsy follow-up. In the study group, biopsies showed LSIL in 41 cases and HSIL in 24. The mean accuracy for a smear diagnosis of LSIL was 60% for the study group and 92% for the control group. For a smear diagnosis of HSIL, the accuracy was 60% for the study group and 95% for the control group. The overall kappa value for the study group confirmed poor interobserver agreement. Some keratinizing SILs are difficult if not impossible to grade precisely using standard criteria. For such lesions, the diagnosis "SIL, grade cannot be determined due to extensive keratinization" is justified.     

The value of duplicate slides on atypical squamous cells, cannot exclude high-grade intraepithelial lesion

Atypical squamous cells, cannot exclude high-grade squamous intraepithelial lesion (ASC-H) category was added to the 2001 Bethesda System. ASC-H accounts for a small percentage (0.2-0.6%) of abnormal Pap smears and includes heterogenous group of lesions. There are more high-grade cervical lesions (30-50%) in ASC-H than ASC-US (10-15%). An accurate Pap diagnosis is crucial for appropriate patient follow-up and treatment. A total of 43 consecutive ASC-H cases were collected from October 2007 to March 2008, and all duplicate and the original slides were reviewed blindly at the end of the study. On review of the duplicate Pap slides, 18 cases had diagnostic SIL cells (15 HSIL, 2 LSIL with ASC-H, and 1 LSIL). The duplicate slides could have potentially changed 18 (41.9%) ASC-H diagnoses to a more definitive SIL diagnosis. On review of the original Pap slides, 8 of these 18 cases also had HSIL cells. Twenty-one follow-up cervical biopsies (21/43, 48.8%) showed 12 CIN 2/3, 4 CIN 1, 1 VAIN 1, 2 cervical polyps, 1 negative for dysplasia, and 1 insufficient for diagnosis. The CIN 2/3 rate was 57.1% (12/21) based on the original ASC-H Pap diagnosis. The CIN 2/3 rates were 80% (8/10) with SIL cells on duplicate slides and 36.4% (4/11) without SIL cases on duplicate slides. Our study suggested that duplicate slides were very useful for further classification of ASC-H, but other ancillary tests might be necessary for some cases. We propose a systematic approach using combined duplicate slides and reflex HPV testing to further classify ASC-H.     

Abnormal vaginal cytology in HIV-infected and at-risk women after hysterectomy

OBJECTIVE: To determine the frequency of and risk factors for abnormal vaginal Papanicolaou smears in HIV-infected women after hysterectomy. METHODS: Data were from the HIV Epidemiology Research (HER) study, a prospective multisite study of HIV-infected and uninfected women. Semiannual vaginal Papanicolaou smears and colposcopy data were obtained from 102 HIV-infected and 46 at-risk women who had hysterectomy either before or during the study. Analytic models used include Cox proportional hazards (women with hysterectomy during the study) and multiple logistic regressions, which corrected for repeated measures (all women). RESULTS: Among the HIV-infected women, evidence of cervical intraepithelial neoplasia before or at hysterectomy was associated with abnormal cytology during follow-up; 63% had squamous intraepithelial lesions (SIL) on vaginal Papanicolaou smears following hysterectomy. CD4 counts of <200 cells/microL at hysterectomy and HIV viral load of >10,000 copies/mL at hysterectomy were predictive of SIL vaginal cytology. Prevalent SIL vaginal cytology was associated with low CD4 count and human papillomavirus risk type. Of the 102 HIV-infected women, 16 (16%) had vaginal intraepithelial neoplasia on biopsy. CONCLUSIONS: The high rate of SIL on vaginal Papanicolaou smears and the presence of high-grade vaginal intraepithelial neoplasia among HIV-infected women after hysterectomy demonstrate the need for continued follow-up for lower genital tract lesions.     

The clinical significance of "squamous intraepithelial lesion of indeterminate grade" as a distinct cytologic category

The histologic and/or cytologic follow-up of 127 cases of cervical lesions termed "squamous intraepithelial lesion of indeterminate grade" (SIL) on Papanicolaou (Pap) smears by the 2001 Bethesda System was compared with 150 control cases of low-grade SIL (LSIL), high-grade SIL (HSIL), and atypical squamous cells, cannot exclude HSIL (ASC-H). A follow-up diagnosis of cervical intraepithelial neoplasia (CIN) 2 or higher was identified in 22.8% of SIL cases, which was 2.6 times higher than LSIL, 3 times lower than HSIL, and 1.5 times lower than ASC-H. A follow-up diagnosis of CIN 1 was identified in 31.5% of SIL cases, which was 2 times lower than the LSIL group, 1.5 times higher than the ASC-H cases, and 1.8 times higher than the HSIL group. We found that 22.0% of cases diagnosed as SIL were followed up by Pap smears rather than colposcopy and biopsy, compared with about 1% of LSIL and HSIL cases. Because SIL cases have a significant risk of harboring CIN 2 or greater, we recommend follow-up by colposcopy and biopsy.     

Cathepsin E expression by normal and premalignant cervical epithelium.

We have investigated the expression of the aspartic proteinase cathepsin E and HLA-DR and the presence of HPV16 in normal squamous epithelium (n = 8) and low-grade (n = 21) and high-grade (n = 14) intraepithelial squamous lesions of the uterine cervix. Immunohistochemistry of cervical biopsies revealed that up-regulation of cathepsin E expression was related to increasing severity of the cervical intraepithelial neoplasia (CIN). Up-regulation of protein was associated with increased message as assessed by in situ hybridization. Langerhans cells and the majority of koilocytes did not express detectable cathepsin E levels. Although there was also an up-regulation of HLA-DR expression by cervical keratinocytes in cervical intraepithelial neoplasia lesions, as determined by immunohistochemistry, no significant correlation was found between HLA-DR and cathepsin E expression in these lesions; neither was expression of cathepsin E correlated to the presence of HPV16, detected by polymerase chain reaction. The expression of cathepsin E, an aspartic proteinase that is reported to play a role in antigen processing for presentation by class II major histocompatibility complex molecules, is associated with cellular dedifferentiation in cervical intraepithelial neoplasia.     

Evaluation of a cervical cytology device (cell-sweep) based on comparison to colposcopic findings.

A new cytology sampling device, the CellSweep, identifies squamous intraepithelial lesions with a sensitivity of 75%. The purpose of this study was to evaluate the accuracy of cervical cytology using a new sampling device combining an endocervical brush and ectocervical spatula into one unit (CellSweep, patented by R. Mohajer, Troy, Michigan). From April 1995 to July 1995, 71 patients referred to the Allegheny University Hospitals Colposcopy Clinic had cervical cytology obtained with the CellSweep and underwent colposcopic evaluation of the cervix. The ability of the CellSweep to detect an abnormality confirmed by colposcopic evaluation was studied. Colposcopically directed ectocervical biopsies were obtained only in patients with identifiable lesions (n = 32). No random biopsies were obtained. The cytology smear was unsatisfactory for interpretation in one case. The remaining 70 Papanicolaou smears were read as normal in 17 (24%) cases and atypical squamous cells in 19 (27%). A squamous intraepithelial lesion (SIL) was detected in 34 (48%) smears. The colposcopic evaluation was normal in 50 patients who had satisfactory Papanicolaou smears, whereas SIL was detected in 20 cases. In 31 patients, SIL was not present in either colposcopy or cytology. In this preliminary study, the CellSweep identified SIL with a sensitivity of 75% and a specificity of 62%. The CellSweep, which combines an endocervical brush and an ectocervical spatula into a single unit, seems to be an acceptable device for obtaining cervical cells for cytologic screening.     

Increased secretion patterns of interleukin-10 and tumor necrosis factor-alpha in cervical squamous intraepithelial lesions

Cytokines are released in response to infection of the uterine cervix by high-risk HPV. By using enzyme-linked immunosorbent assay, we measured the levels of tumor necrosis factor-alpha (TNF-alpha), interferon-gamma (INF-gamma), interleukin-6 (IL-6), and interleukin-10 (IL-10) in the cervical secretions of 120 cytologically normal or equivocal and 91 abnormal Japanese women. HPV infection of the cervical cells was typed by the LCR-E7 PCR method. The HPV DNA-negative samples were classified as either normal or inflamed, and the HPV DNA-positive samples were classified as HPV positive(+) n-ormal and as low- or high-grade squamous intraepithelial lesions (SILs). Compared with the normal cervices, all of the cytokines tested were elevated in inflamed, HPV+ normal, low-grade SILs (LSIL), and high-grade SILs (HSIL). The level of IL-10 was statistically higher in LSIL, and the level of TNF-alpha was higher in HSIL, relative to the cytokine levels in the inflamed and HPV+ normal samples (P <0.05; Mann-Whitney test). Multivariate analyses confirmed that increased levels of IL-10 were associated with LSIL (relative risk [RR]=3.9, 95% confidence interval [CI]=1.7-8.8) and that increased levels of TNF-alpha (RR=4.6, 95% CI=1.4-15) and age older than 40 years (RR=8.5, 95% CI=1.3-56) were associated with HSIL. The levels of INF-gamma and TNF-alpha (Th1-cytokines) correlated negatively with those of IL-6 and IL-10 (Th2-cytokines) in HPV+ normal and LSIL subjects, whereas no such correlation was observed for HSIL. The up-regulated secretion of IL-10 may inhibit immune responses against HPV infection in early cervical lesions, whereas up-regulated TNF-alpha and uncoordinated cytokine secretion (elevated both Th1 and Th2 cytokines) may reflect impaired or invalid responses in advanced stage lesions. The detection of IL-10 and TNF-alpha in cervical secretions may be a useful indicator of local immune responses and of the stage of the cervical lesions induced by HPV infection.     

Immunocytochemical staining of p16INK4a protein from conventional Pap test and its association with human papillomavirus infection

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.