Evaluating the Performance of p16INK4a Immunocytochemistry in Cervical Cancer Screening

The Expression of Testin, Ki-67 and p16 in Cervical Cancer Diagnostics

Testin is a protein expressed in normal human tissues, being responsible, with other cytoskeleton proteins, for the proper functioning of cell−cell junction areas and focal adhesion plaques. It takes part in the regulation of actin filament changes during cell spreading and motility. Loss of heterozygosity in the testin-encoding gene results in altered protein expression in many malignancies, as partly described for cervical cancer. The aim of our study was the assessment of the immunohistochemical (IHC) expression of testin in cervical cancer and its analysis in regard to clinical data as well the expression of the Ki-67 antigen and p16 protein. Moreover, testin expression was assessed by Western blot (WB) in commercially available cell lines. The IHC analysis disclosed that the expression of testin inversely correlated with p16 (r = −0.2104, p < 0.0465) and Ki-67 expression (r = −0.2359, p < 0.0278). Moreover, weaker testin expression was observed in cancer cases vs. control ones (p < 0.0113). The WB analysis of testin expression in the cervical cancer cell lines corresponded to the IHC results and showed a weaker expression compared to that in the control cell line. When we compared the expression of testin in cervical cancer cell lines, we found a weaker expression in HPV-negative cell lines. In summary, we found that the intensity of testin expression and the number of positive cells inversely correlated with the expression of Ki-67 (a marker of proliferation) and p16 (a marker of cell cycle dysregulation). This study shows that the combined assessment of testin, Ki-67 and p16 expression may improve cervical cancer diagnostics.

The Application of Liquid-Based Cytological Detection for P16, Cytologic Evaluation and High-Risk Human Papillomavirus Testing in Cervical Cancer Screening: A Clinical Evaluation

Objective

The aim of this study was to clinically evaluate the application of liquid-based cytology P16, cytologic evaluation, and high-risk human papillomavirus (HR-HPV) testing in cervical cancer screening.

Methods

This study screened 900 women, who attended the outpatient clinic, according to the exclusion criteria of study participants. The study participants’ screening results of liquid-based cytology P16, cytologic evaluation, and HR-HPV testing were analyzed. According to the pathological results of the biopsy, the efficacy of different screening strategies for the identification of high-grade lesions was evaluated.

Results

The positive rate of p16 expression increased with the severity of cervical lesions. P16 had the highest sensitivity and negative predictive value in identifying high-grade lesions (98.45% and 99.67%, respectively). Liquid-based Papanicolaou test (LBP), on the other hand, had the lowest sensitivity (85.27%) but the highest specificity (85.88%). HR-HPV’s positive predictive value and accuracy rate were the lowest (32.77% and 70.03%, respectively). The difference was statistically significant (P < 0.05). Dual combinations of certain tests were set up for this study; P16+LBP, HPV+LBP, and P16+HPV had sensitivities of 98.45%, 96.90%, and 99.22%, and specificities of 80.29%, 63.42%, and 64.33%, respectively. The P16 screening rates of histological and liquid-based cytology approaches were 75.74%.

Conclusion

Compared with traditional LBP+HPV, the application of a test that solely screen for P16 or the combined screening method that involves the screening of P16 is more effective in identifying high-grade lesions.

Evaluation of p16INK4a immunocytology and human papillomavirus (HPV) genotyping triage after primary HPV cervical cancer screening on self-samples in China

OBJECTIVE

Self-sampling for human papillomavirus (HPV) testing is an effective option to increase the cervical screening coverage. How to best triage HPV-positive self-samples remains controversial. Here, we evaluated the performance of a novel p16^INK4a immunocytology approach (p16) and HPV genotyping in triaging HPV-positive self-samples.

METHODS

A cohort of 73699 women were screened via SeqHPV assay on self-samples. HPV-positive women who met any sequential positive result of HPV16/18 or VIA or p16 were referred for colposcopy. A triage strategy was considered favorable if the NPV for CIN3+ was ≥98%, combined with an improvement of sensitivity and specificity in comparison to the comparator, being the 'ASC-US+' triage and the guideline strategy (HPV16/18+ or ASC-US+).

RESULTS

A total of 3510 HPV-positive women were included, 422 (12.0%) CIN2+ and 247 (7.0%) CIN3+ were identified. The positivity of p16 and ASC-US+ were 36.3% and 22.2%, respectively. p16 was more sensitive and less specific than ASC-US+ (P < 0.0001). However, when combined p16 with cytology or genotypes, two triage strategies were superior to the 'ASC-US+' strategy: p16 scored 3+; HPV16/33/58/31+ &p16+. Moreover, four strategies were favorable to the guideline strategy: ASC-US+ or p16+; LSIL+ or p16+; HPV16+ or p16+; HSIL+ or p16+ or HPV16+. These strategies achieved better balance between diseases detection and colposcopy referral.

CONCLUSIONS

Our findings indicate the promising utility of p16 immunocytology via adjusting the staining score or serving as an ancillary tool to liquid-based cytology or combining with genotyping for the triage of HPV-positive self-samples, which promotes the precise screening of cervical cancer.

Triaging HPV-positive, cytology-negative cervical cancer screening results with extended HPV genotyping and p16INK4a immunostaining in China

Background

Self-sampling for human papillomavirus (HPV) testing is a feasible option to improve the cervical screening coverage. However, an ideal triage method for HPV-positive self-samples does not yet exist. The aim of this study was to explore the utility of HPV genotyping and p16^INK4a immunostaining (p16) in triaging HPV-positive self-samples, focusing on HPV-positive, cytology-negative (HPCN) women.

Methods

A total of 73,699 women were screened in a cervical screening project in China via SeqHPV assay on self-samples. HPV-positive women were called-back and collected cervical sample for p16 immunostaining and liquid-based cytology, those who met any result of HPV16/18+ or visual inspection with acetic acid (VIA) + or p16+ were referred for colposcopy, and HPCN women with adequate data on p16 and pathology were analyzed. A triage strategy was considered acceptable if the negative predictive value (NPV) for cervical intraepithelial neoplasia 3 or worse (CIN3+) was 98% or more, combined with an improvement of sensitivity and specificity for CIN2+/CIN3+ in reference to the comparator, being HPV16/18 + .

Results

A total of 2731 HPCN women aged 30–64 years were enrolled, 136 (5.0%) CIN2+ and 53 (1.9%) CIN3+ were detected. Five triage strategies met the criteria: p16+; HPV16/33+; ‘HPV16+ or HPV33/58/31/35+&p16+’; ‘HPV16/33+ or HPV58/31/35+&p16+’; HPV16/18/31/33/45/52/58 + & p16+. These strategies required less or similar colposcopy referrals, and less colposcopies to detected one case of CIN2+/CIN3+, achieving favorable false positive (negative) rates to the comparator. Among them, p16 staining detected 83.1% (79.2%) of underlying CIN2 + (CIN3+) in HPCN women. Moreover, three triage strategies were favorable in sensitivity and/or specificity to the ‘HPV16/33+’ strategy: p16+; ‘HPV16+ or HPV33/58/31/35 + &p16+’; HPV16/18/31/33/45/52/58 + &p16 + .

Conclusions

Genotyping for HPV16/33 could be utilized to optimize the management of HPCN women. Moreover, p16 immunostaining, either alone or combined with extended genotypes, is more effective than HPV genotypes alone in the triage of HPCN women.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06109-4.

Clinical evaluation of p16INK4a immunocytology in cervical cancer screening: A population-based cross-sectional study from rural China

BACKGROUND

Cervical cancer screening with cytology suffers from low sensitivity, whereas the efficiency of human papillomavirus (HPV)-based screening is limited by low specificity. The authors evaluated a novel p16^INK4a immunocytology approach in cervical cancer screening compared with HPV-based and cytology-based screening.

METHODS

In total, 2112 women aged 49 to 69 years from Shanxi, China were screened from March to July 2019. HPV testing, liquid-based cytology (LBC), and p16^INK4a immunocytology were performed on samples from all women. Any positive result triggered a referral to colposcopy with biopsy, if indicated. Screening performance for detecting cervical intraepithelial neoplasia grade 2 and 3 or worse (CIN2+/CIN3+) was evaluated using multiple algorithms.

RESULTS

p16^INK4a had a lower positive rate (10.0%) than LBC abnormality (vs 12.1%; P = .004) and a high-risk HPV positivity (21.4%; P < .001). For the detection of CIN3+, the relative sensitivity of p16^INK4a compared with HPV and LBC was 0.93 (95% CI, 0.82-1.07) and 1.12 (95% CI, 0.95-1.32), respectively. The specificity of p16^INK4a was significantly higher than that for HPV and LBC, with a relative specificity of 1.13 (95% CI, 1.11-1.16) and 1.02 (95% CI, 1.01-1.04), respectively. In addition, p16^INK4a alone yielded a clinical performance very similar to that of the current mainstream strategy of using HPV16/18 with reflex cytology (ASC-US+, atypical squamous cells of undetermined significance or worse). The immediate risk of CIN3+ was 14.6% if p16^INK4a results were positive and 0.2% if p16^INK4a results were negative.

CONCLUSIONS

With minimal colposcopy referrals, p16^INK4a screening demonstrated promising utility for risk stratification and yielded a better balance between sensitivity and specificity compared with HPV and LBC primary screening. Moreover, with accuracy and efficiency similar to what is achieved using mainstream cotest algorithms, p16 may simplify the screening practice. More evidence will be required before clinical recommendation.

In situ immunopathological events in human cervical intraepithelial neoplasia and cervical cancer: Review

Neoplasia of the cervix represents one of the most common cancers in women. Clinical and molecular research has identified immunological impairment in squamous intraepithelial cervical lesions and cervical cancer patients. The in-situ expression of several cytokines by uterine epithelial cells and by infiltrating leukocytes occurs during the cervical intraepithelial neoplasia and cervical cancer. Some of these cytokines can prevent and others can induce the progression of the neoplasm. The infiltrating leukocytes also produce cytokines and growth factors relate to angiogenesis, chemotaxis, and apoptosis capable of modulating the dysplasia progression. In this review we analyzed several interleukins with an inductive effect or blocking effect on the neoplastic progression. We also analyze the genetic polymorphism of some cytokines and their relationship with the risk of developing cervical neoplasia. In addition, we describe the leukocyte cells that infiltrate the cervical uterine tissue during the neoplasia and their effects on neoplasia progression.

Methodologies of Primary HPV Testing Currently Applied for Cervical Cancer Screening

The human papillomavirus is one of the most common sexually transmitted viruses, and an infection from this virus may become persistent, leading to diseases such as cervical cancer. In the past, cytology-based methods such as the Papanicolaou (Pap) test were imperative to identify the disease at a stage where it can be treated. However, since the 1980s where the etiological association of HPV and cervical cancer was identified, new tests began emerging directed towards identifying the virus. Furthermore, as the biology of HPV along with the relationships with its host are elucidated, these tests and treatments further advance. Recently in Europe, there is a movement towards the implementation of HPV testing methodologies in national screening programs to precede cytological testing. These screening strategies are recommended by the European guidelines and the World Health Organization. This review presents the current HPV testing methodologies, their application in organized population-based cervical cancer screening programs based on the most recent European guidelines, and their implementation status in countries in Europe.