A pilot evaluation of a novel immunohistochemical assay for topoisomerase II-alpha and minichromosome maintenance protein 2 expression (ProEx C) in cervical adenocarcinoma in situ, adenocarcinoma, and benign glandular mimics

MCM2 in human cancer: functions, mechanisms, and clinical significance

Background

Aberrant DNA replication is the main source of genomic instability that leads to tumorigenesis and progression. MCM2, a core subunit of eukaryotic helicase, plays a vital role in DNA replication. The dysfunction of MCM2 results in the occurrence and progression of multiple cancers through impairing DNA replication and cell proliferation.

Conclusions

MCM2 is a vital regulator in DNA replication. The overexpression of MCM2 was detected in multiple types of cancers, and the dysfunction of MCM2 was correlated with the progression and poor prognoses of malignant tumors. According to the altered expression of MCM2 and its correlation with clinicopathological features of cancer patients, MCM2 was thought to be a sensitive biomarker for cancer diagnosis, prognosis, and chemotherapy response. The anti-tumor effect induced by MCM2 inhibition implies the potential of MCM2 to be a novel therapeutic target for cancer treatment. Since DNA replication stress, which may stimulate anti-tumor immunity, frequently occurs in MCM2 deficient cells, it also proposes the possibility that MCM2 targeting improves the effect of tumor immunotherapy.

Surrogate markers for high-risk human papillomavirus infection in oral epithelial dysplasia: A comparison of p16, Ki-67, and ProExC

OBJECTIVE

The aim of this study was to determine the utility of surrogate markers of human papillomavirus (HPV) infection in the diagnosis of HPV-associated oral epithelial dysplasia (OED).

STUDY DESIGN

Twelve cases of oral dysplasia with histologic features of HPV infection were stained with surrogate markers for HPV (p16, Ki-67, and ProExC) on immunohistochemistry. A second group of 12 cases of oral dysplasia without histologic features of HPV infection was used for comparison. Reverse transcriptase polymerase chain reaction (RT-PCR) was used to confirm the presence of high-risk HPV (HR HPV) in p16-positive cases.

RESULTS

All of the surrogate markers showed a statistically significant association with HPV-positive OED (P < .001). The agreement between p16 and HPV positivity was the strongest (κ = 1.00), whereas Ki-67 showed very good association with HPV (κ = 0.83), and ProExC showed good association (κ = 0.75). In each case, the agreement was statistically significant (P < .001). Overall, each of the 3 markers showed good sensitivity; however, ProExC showed the lowest specificity.

CONCLUSIONS

The clinicopathologic features of 12 cases of HPV OED are reported. Diffuse p16 positivity is an accurate and reliable method for predicting HR HPV infection in both high and low grade cases of epithelial dysplasia with histopathologic features of HPV OED. The use of Ki-67 and ProExC did not demonstrate any additional diagnostic benefit in the diagnosis HPV OED.

ProEx C as Diagnostic Marker for Detection of Urothelial Carcinoma in Urinary Samples: A Review

The gold standard for the detection of urothelial carcinoma is represented by urethro-cystoscopy and biopsy. Both procedures are invasive and expensive and therefore cytology is often used as first approach to investigate on a possible neoplasia, being a safe and cost-effective diagnostic modality of evaluation. Because cytology alone is not highly sensitive for detection of low grade urothelial carcinoma and recurrence of the disease, several adjunct markers and urine based tests for urothelial carcinoma have been developed, which can help in the final diagnosis. In particular, ProEx C is an immunohistochemical cocktail containing antibodies direct against topoisomerase IIα (TOP2A) and minichromosome maintenance 2 (MCM2) proteins. It proved to be a valid biomarker especially in detecting squamous intraepithelial lesions in cervical liquid-based samples and in discerning these lesions from their mimickers, as well as in ovarian, endometrial, vulvar, primary and metastatic melanomas, breast, pancreatic and renal cell carcinomas. This brief review covers the effective utility of ProEx C as adjunct tool in assessing the urothelial lesions in urine cytology, also providing prognostic and therapeutic information to help in clinical decisions.

MCM7 expression is a promising predictor of recurrence in patients surgically resected for meningiomas

Patients with high risk of recurrence after meningioma resection might benefit from adjuvant radiation therapy and closer clinical follow-up. While the World Health Organization (WHO) classification and the MIB-1 biomarker are applied in the clinical practice to identify these patients, the reliability of these methods is questionable. To improve the prediction of tumor recurrence, this study evaluated and compared the prognostic usefulness of the biomarker MCM7 with the conventional mitotic index and the MIB-1 biomarker. One hundred sixty patients were retrospectively analyzed. The expression of MIB-1 and MCM7 was determined as proliferative indices (PI-percentage of positive immunoreactive cells among 1000 tumor cells) in tissue microarrays. MCM7 PI revealed significantly higher indices in recurrent meningiomas compared with non-recurrent meningiomas (p = 0.020), while mitotic index and MIB-1 PI did not reach statistical significance (p ≥ 0.547). The optimal cutoff values for recurrence prediction were 3% for MIB-1 PI and 8% for MCM7 PI. MCM7 PI was significantly associated with recurrence-free survival in COX multivariate survival analyses (p = 0.005), while no association was found with mitotic index or MIB-1 (p ≥ 0.153). MCM7 PI allowed for the most accurate prediction of recurrence, obtaining the highest sensitivity and the greatest area under the ROC curve. These results proved that MCM7 PI is a better method for identifying patients with risk of recurrence compared with the traditional methods used in the current clinical practice. MCM7 may thus improve diagnostics, prediction of prognosis and treatment decision making in patients suffering from meningiomas.

Expression of ProEx C in primary and metastatic urothelial carcinoma

BACKGROUND

ProEx C is an antibody cocktail targeting the expression of topoisomerase IIα and minichromosome maintenance protein-2. Both these proteins are over-expressed in the cell nucleus during aberrant S-phase induction of neoplastic cells, which leads to cell proliferation. The aim of this study was to determine whether ProEx C expression can detect primary and metastatic urothelial carcinoma (UC).

METHODS

Thirty one fine needle aspiration cell blocks (CB) with metastatic UC were identified. Immunohistochemical staining for ProEx C and thrombomodulin was performed. Additionally, staining for Pro Ex C was also performed in tissue microarrays (TMA) of 46 cases of primary UC and carcinomas from colon (80), stomach (31), pancreas (33), liver (92), ovary (24), endometrium (25), breast (60), lung (27), kidney (32), and prostate (44), as well as melanoma (22). Nuclear staining of ProEx C and membrane staining of thrombomodulin in at least 10% tumor cells was considered a positive result.

RESULTS

Both ProEx C and thrombomodulin have similar sensitivity for metastatic UC (84% vs. 77%, p=0.75; whereas ProEx C yielded a higher sensitivity of 93% for primary UC than thrombomodulin (72%, p=0.01). In addition to UC, ProEx C is also expressed in most of the malignant neoplasms tested in our TMA study, and has the highest sensitivity in colon and stomach carcinomas (94%).

CONCLUSION

ProEx C has high sensitivity for UC. However, it is also expressed in carcinomas of colon, stomach, breast, and lung carcinomas and may not be a useful marker for workup of metastatic UC.

The spectrum of cervical glandular neoplasia and issues in differential diagnosis

CONTEXT

Premalignant and malignant glandular lesions of the cervix are known to often cause diagnostic problems with a variety of benign (more common) as well as other malignant mimics, the latter setting often being represented by secondary involvement by endometrioid endometrial carcinoma especially in small samplings.

OBJECTIVE

To highlight key histologic features and immunohistochemical markers that may be helpful in the distinction of in situ endocervical carcinoma from benign glandular proliferations, and those that separate different subtypes of invasive endocervical carcinoma, as well as invasive carcinoma from other carcinomas secondarily involving the cervix and nonneoplastic proliferations of the cervix.

CONCLUSIONS

Clinical and morphologic features as well as immunohistochemistry results should be used in conjunction in the differential diagnosis of glandular proliferations of the cervix, as correct interpretation has major clinical consequences for the patient in most instances (especially benign versus malignant). Immunohistochemical markers should be used as part of a panel of antibodies, as exceptions may occur to the usual pattern of staining, and if used singly, they may mislead the pathologist to establish a wrong diagnosis.

Molecular targets of HPV oncoproteins: potential biomarkers for cervical carcinogenesis

Cervical cancer is the second most common cancer among women worldwide and is responsible for 275,000 deaths each year. Persistent infection with high-risk human papillomavirus (HR-HPV) is an essential factor for the development of cervical cancer. Although the process is not fully understood, molecular mechanisms caused by HPV infection are necessary for its development and reveal a large number of potential biomarkers for diagnosis and prognosis. These molecules are host genes and/or proteins, and cellular microRNAs involved in cell cycle regulation that result from disturbed expression of HR-HPV E5, E6 and E7 oncoproteins. One of the current challenges in medicine is to discover potent biomarkers that can correctly diagnose cervical premalignant lesions and standardize clinical management. Currently, studies are showing that some of these molecules are potential biomarkers of cervical carcinogenesis, and it is possible to carry out a more accurate diagnosis and provide more appropriate follow-up treatment for women with cervical dysplasia. In this paper, we review recent research studies on cell cycle molecules deregulated by HPV infections, as well as their potential use for cervical cancer screening.

Evaluation of ProExC as a prognostic marker in oropharyngeal squamous cell carcinomas

ProExC expression has been shown to perform similarly to p16 as an aid in the diagnosis of cervical dysplasia but has not been well characterized in head and neck squamous cell carcinomas (SCC). The purpose of this study is to determine whether ProExC performs similarly to p16 as a prognostic marker in oropharyngeal SCC and to evaluate the threshold of ProExC and p16 staining that correlates with survival. ProExC, p16, and human papillomavirus DNA in situ hybridization were performed on tissue microarray (TMA) cores and whole sections from 62 patients with oropharyngeal SCC. Sensitivity and specificity for high-risk HPV and correlation with overall survival (OS), cancer-specific survival (CSS), and time to distant metastasis (TDM) were calculated for ProExC and p16 at different thresholds. ProExC did not prove to be a robust marker. It showed strong correlation with OS at a 66% threshold on TMA cores, but correlation with OS was lost on whole sections. It also exhibited low sensitivity (53.7%) on TMA cores and low specificity on whole sections (65%). ProExC at a 33% threshold exhibited unacceptably low specificity and did not correlate with OS, CSS, or TDM. Sensitivity and specificity of p16 varied predictably with threshold: higher sensitivity and lower specificity with lower thresholds and vice versa for higher thresholds. p16 at a 50% threshold offers a balance between sensitivity and specificity, and correlates with OS, CSS, and TDM on whole sections; correlation with TDM is lost on TMA cores. These findings indicate that ProExC does not perform well enough to be used as a prognostic marker in oropharyngeal SCC. p16 should be used and scored as positive when at least half the tumor is strongly stained.

Expression of minichromosome maintenance MCM6 protein in meningiomas is strongly correlated with histologic grade and clinical outcome

The 2007 World Health Organization histologic grading of meningiomas is associated with recurrence and clinical outcome. However, distinction of grade I from grade II (atypical) meningiomas can be challenging. In the World Health Organization classification, there are 4 parameters on the basis of which grade II status can be determined: mitotic rate, cytoarchitectural features, brain invasion, and/or histologic subtype. Furthermore, this classification fails to detect grade I recurrent meningiomas, for which other prognostic criteria would be needed. The aim of this study was to evaluate the respective value of several markers involved in cell cycle as effective tools to predict recurrence. This retrospective study was based on a series of 59 meningiomas (grade I: 32 of 59, grade II: 27 of 59, all harboring ≥4 mitoses/1.6 mm), analyzed with the following immunohistochemical markers: MCM6, Ki-67, PHH3, cyclin D1, and p53. We found a significant correlation between histologic grade and mean labeling index for MCM6 (grade I: 21.8% vs. grade II: 65.8%; P<0.001), Ki-67 (3.2% vs. 16.9%; P<0.001), PHH3 (0.7‰ vs. 2.8‰; P<0.001), cyclin D1 (50.4% vs. 70.0%; P=0.005), and p53 (17.3% vs. 32.4%; P=0.017). Histologic grading and mitotic index were correlated with progression-free survival (P=0.010 and P=0.020, respectively). A nearly linear correlation was found between progression-free survival and staining for MCM6 (P<0.001), Ki-67 (P=0.003), and PHH3 (P=0.037) but not for cyclin D1 (P=0.400) and p53 (P=0.758). The interobserver agreement coefficients for MCM6, Ki-67, PHH3, cyclin D1, and p53 were, respectively, 0.97 (95% confidence interval, 0.95-0.98), 0.93 (0.89-0.96), 0.81 (0.70-0.88), 0.90 (0.83-0.94), and 0.84 (0.73-0.90). In conclusion, because of its strong level of expression and sharp difference in labeling index between indolent and recurrent tumors, MCM6 is the most efficient marker to identify tumors with a high risk of recurrence.

Role of protein biomarkers in the detection of high-grade disease in cervical cancer screening programs

Since the Pap test was introduced in the 1940s, there has been an approximately 70% reduction in the incidence of squamous cell cervical cancers in many developed countries by the application of organized and opportunistic screening programs. The efficacy of the Pap test, however, is hampered by high interobserver variability and high false-negative and false-positive rates. The use of biomarkers has demonstrated the ability to overcome these issues, leading to improved positive predictive value of cervical screening results. In addition, the introduction of HPV primary screening programs will necessitate the use of a follow-up test with high specificity to triage the high number of HPV-positive tests. This paper will focus on protein biomarkers currently available for use in cervical cancer screening, which appear to improve the detection of women at greatest risk for developing cervical cancer, including Ki-67, p16^INK4a, BD ProEx C, and Cytoactiv HPV L1.

Neoplastic Lesions of the Cervix

This review presents a discussion of the gross and microscopic features, diagnosis, differential diagnosis, and prognosis of neoplastic lesions of the cervix. Biomarkers are discussed for each entity presented - cervical intraepithelial neoplasia, squamous carcinoma, glandular neoplasms, adenocarcinoma in situ, adenosquamous carcinoma, and others.

A panel of 3 markers including p16, ProExC, or HPV ISH is optimal for distinguishing between primary endometrial and endocervical adenocarcinomas

Endometrial and endocervical adenocarcinomas may seem histologically identical and it can be difficult to determine primary site of origin based on morphology alone. As the distinction is significant and cannot always be made on the basis of clinical findings, various immunohistochemical panels have been proposed to aid in determining site of origin. Stains for vimentin, estrogen receptor (ER), progesterone receptor (PR), monoclonal carcinoembryonic antigen, p16 and ProExC, and HPV in situ hybridization (ISH), were performed on 283 tissue microarray (TMA) cores and 38 whole sections. The TMA consisted of 214 endometrial carcinomas, 33 endocervical adenocarcinomas, and 36 problematic cases. The endometrial and endocervical carcinomas represented usual endometrioid and mucinous types, and special variants (uterine serous carcinoma, uterine clear cell carcinoma, minimal deviation endocervical adenocarcinoma, cervical small cell carcinoma, adenoid basal cell carcinoma, mesonephric carcinoma). Univariate analysis showed that 6 markers (vimentin, ER, PR, p16, ProExC, and HPV ISH) performed well in distinguishing between endocervical and endometrial origin for the usual endometrioid and mucinous types. Multivariate analysis showed that vimentin, p16, and HPV ISH are the strongest predictors of site. Using a script written in R, the diagnostic accuracy of all possible combinations of markers was evaluated and it was shown that a 3 marker panel including vimentin, ER, or PR, and an HPV marker (p16, ProExC, or HPV ISH) is optimal for determining site of origin for usual endometrial and endocervical adenocarcinomas. However, these panels do not perform well with special variant carcinomas.