High-grade ovarian serous carcinoma exhibits significantly higher p16 expression than low-grade serous carcinoma and serous borderline tumour

Low-Grade Serous Carcinoma of the Ovary: The Current Status

Low-grade serous carcinoma (LGSC) of the ovary is a rare histological subtype of epithelial ovarian carcinoma. It has distinct clinical behavior and a specific molecular profile. Compared with high-grade serous carcinoma, this tumor presents at a younger age, has an indolent course, and is associated with prolonged survival. LGSC can arise de novo or originate following a serous borderline tumor (SBT). Pathological differentiation between LGSC and other ovarian carcinoma histological subtypes is fundamental. Several factors might influence the overall outcome, such as the age at diagnosis, current smoking, elevated body mass index, mutational status, hormonal receptors’ expression, and Ki-67 proliferation index. Surgery is the main treatment option in LGSC, and efforts must be maximized to achieve a microscopic residual in metastatic disease. Despite being relatively chemo-resistant, adjuvant platinum-based chemotherapy remains the standard of care in LGSC. Hormonal maintenance therapy after adjuvant chemotherapy results in improved outcomes. Treatment options for disease recurrence include secondary cytoreductive surgery, chemotherapy, hormonal therapy, targeted therapy, and clinical trials. Advancements in genomic studies and targeted therapies are expected to change the treatment landscape in LGSC.

Development of a 3D functional assay and identification of biomarkers, predictive for response of high-grade serous ovarian cancer (HGSOC) patients to poly-ADP ribose polymerase inhibitors (PARPis): targeted therapy

Background

Poly(ADP-ribose) polymerase inhibitors (PARPis) specifically target homologous recombination deficiency (HRD) cells and display good therapeutic effect in women with advanced-stage BRCA1/2-mutated breast and epithelial ovarian cancer (EOC). However, about 50% of high grade serous ovarian cancers (HGSOC) present with HRD due to epigenetic BRCA1 inactivation, as well as genetic/epigenetic inactivation(s) of other HR genes, a feature known as “BRCAness”. Therefore, there is a potential for extending the use of PARPis to these patients if HR status can be identified.

Methods

We have developed a 3D (spheroid) functional assay to assess the sensitivity of two PARPis (niraparib and olaparib) in ascites-derived primary cell cultures (AsPCs) from HGSOC patients. A method for AsPCs preparation was established based on a matrix (agarose), allowing for easy isolation and successive propagation of monolayer and 3D AsPCs. Based on this method, we performed cytotoxicity assays on 42 AsPCs grown both as monolayers and spheroids.

Results

The response to PARPis treatment in monolayer AsPCs, was significantly higher, compared to 3D AsPCs, as 88% and 52% of the monolayer AsPCs displayed sensitivity to niraparib and olaparib respectively, while 66% of the 3D AsPCs were sensitive to niraparib and 38% to olaparib, the latter being more consistent with previous estimates of HRD (40%–60%) in EOC. Moreover, niraparib displayed a significantly stronger cytotoxic effect in both in 3D and monolayer AsPCs, which was confirmed by consecutive analyses of the HR pathway activity (γH2AX foci formation) in PARPis-sensitive and resistant AsPCs. Global gene expression comparison of 6 PARPi-resistant and 6 PARPi-sensitive 3D AsPCs was indicative for the predominant downregulation of numerous genes and networks with previously demonstrated roles in EOC chemoresistance, suggesting that the PARPis-sensitive AsPCs could display enhanced sensitivity to other chemotherapeutic drugs, commonly applied in cancer management. Microarray data validation identified 24 potential gene biomarkers associated with PARPis sensitivity. The differential expression of 7 selected biomarkers was consecutively confirmed by immunohistochemistry in matched EOC tumor samples.

Conclusion

The application of this assay and the potential biomarkers with possible predictive significance to PARPis therapy of EOC patients now need testing in the setting of a clinical trial.

P16 as a marker of carcinoma in effusions and peritoneal washing

BACKGROUND

Considering the potential of p16 as a marker for diagnosis, prognosis and therapeutic response, the aim of this study was to assess its presence, via immunocytochemistry, in metastatic carcinoma of different primary sites and histological types obtained from effusions and peritoneal washings. A total of 118 samples including 85 of metastatic carcinoma and 33 samples of benign effusion/peritoneal washing were prepared by the plasma/thromboplastin method. Immunocytochemistry reactions were performed on cell block sections using antibodies against p16, claudin-4, MOC-31, calretinin, HBME and CD68.

RESULTS

P16 overexpression was observed in 88.23% of all carcinoma samples. All cervix adenocarcinoma samples showed p16 overexpression. Overexpression in adenocarcinomas of ovary, lung and breast was observed in 93.75, 93.10 and 75% of the samples, respectively. Overexpression was observed in all different histological types analyzed: small cell carcinoma (lung), squamous cell carcinoma (cervical) and urothelial carcinoma (bladder). The specificity of p16 for carcinoma detection was of 96.96%.

CONCLUSION

Overexpression of p16 was observed in most metastatic carcinoma, from different primary sites and histological types, obtained from effusions and peritoneal washings. Due to its high frequency of overexpression in metastatic carcinoma, p16 may play a possible role in tumor progression and it may be considered as a complementary diagnostic marker depending on histological type and primary site of carcinoma.

Neoadjuvant therapy in gynaecological malignancies: What pathologists need to know

In recent times, there has been a growing tendency to treat advanced gynaecological malignancies with neoadjuvant chemotherapy (NACT), with the goal of reducing tumour volume and enhancing operability resulting in optimal cytoreduction. This approach is used in particular for patients with advanced high-grade serous carcinoma of the ovary, fallopian tube or peritoneum. Pathology plays a crucial role in the management of these patients, both before and after NACT. Prior to initiation of NACT, a biopsy should be performed, usually of the omental cake, to confirm that a malignancy is present, to identify the site of origin of the tumour and to type and grade the tumour. Histopathologists must be aware of the resultant morphological effects of NACT when examining specimens following interval cytoreduction surgery. Tumour typing and grading, and even the identification of residual neoplasia, are particular challenges. Immunohistochemistry, when used judiciously, can be a useful adjunct in certain scenarios. A pathological assessment of the response to chemotherapy, and the pathological stage should be provided in the pathology report, as these may inform prognosis and subsequent management. We present a comprehensive overview of the relevant clinical and pathological aspects pertaining to NACT for gynaecological malignancies for the practicing surgical pathologist.

Missing information in statewide and national cancer databases: Correlation with health risk factors, geographic disparities, and outcomes

OBJECTIVE

The objectives of this study were to analyze factors associated with outcomes and missing data in women with epithelial ovarian cancer using institutional, state and national databases.

METHODS

Data were abstracted from the University of Virginia cancer registry, Virginia Department of Health (VDH) database, and Surveillance, Epidemiology, and End Results (SEER) Program and analyzed for correlations with demographics, cancer characteristics, and outcomes. Statewide spatial associations between health risk factors such as smoking, obesity, and missing grade/stage were evaluated using bivariate LiSA in Geoda.

RESULTS

There were 524 institutional, 3544 VDH, and 44,464 SEER cases of epithelial ovarian cancer. Institutional cases were younger, most often of white race, had increased grade 1, and decreased unknown grade and stage (all p < 0.001). Significant predictors of unknown grade were non-white race, older age, no surgery, unknown stage/stage IV, and unknown histology/adenocarcinoma. Unknown grade correlated with a significant survival disadvantage. Missing stage and grade correlated with county-level obesity and smoking, as rural regions in Southwest and Southside Virginia had high rates of health risk factors and missing stage/grade compared to urban, affluent regions in Northern Virginia.

CONCLUSIONS

Over a third of nationally reported cases have an unknown grade and 10-20% have an unknown stage which correlates with the worst survival. Predictors of unknown grade include insurance, age, race, smoking status, obesity, and rural setting. Missing data may represent geographical differences or disparities in cancer care available as significantly fewer cases had an unknown grade/stage at a tertiary academic medical center compared to VDH and SEER.

Serous ovarian tumors: Immunohistochemical profiling as an aid to grading and understanding tumorigenesis

Background

The aim of this study was to evaluate the expression of p53, p16, Wilms tumor gene (WT1), and Mindbomb E3 Ubiquitin Protein Ligase 1 (MIB-1) index by immunohistochemical (IHC) staining in benign, low-grade, and high-grade serous ovarian tumors.

Methods

Forty-one cases of ovarian serous tumors were included in the study (benign serous tumor [n = 10], low-grade ovarian serous carcinoma [n = 8], and high-grade ovarian serous carcinoma [n = 23]). Expression of p53, p16, WT1, and MIB-1 by IHC was evaluated statistically with the grade of tumor. Semiquantitative scoring system for percentage (0-5) and intensity (1-3) of staining pattern was used to bring about objectivity.

Results

p53, p16, and WT1 showed significantly higher staining scores in ovarian serous carcinoma group than in the benign group (p < 0.05). However, p16 score was not significant in benign versus low-grade tumors. In the carcinoma group, the high-grade serous tumors showed significantly higher staining scores of p53, p16, and WT1 than the low-grade serous tumors (p < 0.05). Papillary serous tumors had comparatively lower p53 and WT1 scores for the same grade of tumor. MIB-1 scores were not significant.

Conclusion

p53, p16, and WT1 are helpful for the subtyping of serous ovarian tumors as low grade and high grade. WT1 is helpful in establishing primary ovarian serous tumors. The combination of moderate-to-high p53 and WT1 scores provides a robust way of confirming high-grade tumors.

Immunohistochemical Characterization Improves the Reproducibility of the Histological Diagnosis of Ovarian Carcinoma

Background: Ovarian cancer is the leading cause of gynecologic cancer-related death. Histological assessment remains the standard clue for the diagnosis of ovarian carcinoma. Misinterpretation and inconsistent application of histological criteria may lead to significant interobserver variability and poor reproducibility of the diagnosis. In this study, we investigated the discrepancy in histological diagnosis and the significance of a designed panel of immunohistochemical markers for the improvement of the diagnostic reproducibility of ovarian carcinomas. Methods: We performed a retrospective study on 74 ovarian carcinomas. All tumor slides were independently reviewed by two pathologists. The results for seven available immunomarkers as p53, WT-1, p16INK4A, CK7, CK20, and estrogen and progesterone receptors were determined for all cases by immunohistochemistry. Results: The histological diagnosis review performed using standard histology showed a concordance of diagnoses in 86% of cases with Cohen’s kappa of 0.80. Immunohistochemical results increased significantly the diagnosis reproducibility with a concordance of 91% and a Cohen’s kappa of 0.86 (P = 0.001). Conclusion: Although the histological diagnosis remains reliable, the use of a designed panel of immunohistochemical markers improves significantly the interobserver concordance and the classification accuracy of ovarian carcinomas.

Can Stemness and Chemoresistance Be Therapeutically Targeted via Signaling Pathways in Ovarian Cancer?

Ovarian cancer is the most lethal gynecological malignancy. Poor overall survival, particularly for patients with high grade serous (HGS) ovarian cancer, is often attributed to late stage at diagnosis and relapse following chemotherapy. HGS ovarian cancer is a heterogenous disease in that few genes are consistently mutated between patients. Additionally, HGS ovarian cancer is characterized by high genomic instability. For these reasons, personalized approaches may be necessary for effective treatment and cure. Understanding the molecular mechanisms that contribute to tumor metastasis and chemoresistance are essential to improve survival rates. One favored model for tumor metastasis and chemoresistance is the cancer stem cell (CSC) model. CSCs are cells with enhanced self-renewal properties that are enriched following chemotherapy. Elimination of this cell population is thought to be a mechanism to increase therapeutic response. Therefore, accurate identification of stem cell populations that are most clinically relevant is necessary. While many CSC identifiers (ALDH, OCT4, CD133, and side population) have been established, it is still not clear which population(s) will be most beneficial to target in patients. Therefore, there is a critical need to characterize CSCs with reliable markers and find their weaknesses that will make the CSCs amenable to therapy. Many signaling pathways are implicated for their roles in CSC initiation and maintenance. Therapeutically targeting pathways needed for CSC initiation or maintenance may be an effective way of treating HGS ovarian cancer patients. In conclusion, the prognosis for HGS ovarian cancer may be improved by combining CSC phenotyping with targeted therapies for pathways involved in CSC maintenance.

Combination of TP53 and AGR3 to distinguish ovarian high-grade serous carcinoma from low-grade serous carcinoma

Ovarian high-grade serous carcinoma (HGSC) and low-grade serous carcinoma (LGSC) are distinct gynecologic neoplasms with diverse pathogenesis and characteristic features. They respond differently to same modalities of treatment protocol and have dissimilar prognosis. Thus, it is essential to obtain accurate differential diagnosis of HGSC and LGSC prior to clinical treatment. In the present study, mRNA expression profiles were generated from 5 HGSC and 6 LGSC specimen using HTSeq, and 699 differentially expressed genes (>2-fold difference) were identified using the DESeq R package. Dendrograms produced by unsupervised hierarchical clustering completely distinguished HGSC from LGSC. Among differentially expressed genes between HGSC and LGSC, anterior gradient homolog 3 (AGR3) was highly upregulated in LGSC compared to HGSC, which was validated by reverse transcription‑quantitative polymerase chain reaction and western blotting. Then, anti‑tumor protein 53 (TP53) and anti-AGR3 immunohistochemistry were performed on 145 HGSC and 30 LGSC samples. Consistent with previous studies, abnormal expression of TP53 (0 or ≥75% positive expression) was observed in 87.6% of HGSC and 13.3% of LGSC samples. Positive staining of AGR3 had a sensitivity of 80.0% and specificity of 89.7% for LGSC. TP53 and AGR3 were both efficient in distinguishing HGSC from LGSC (P<0.001). Receiver operating characteristic analysis revealed a similar area under the curve for AGR3 (0.848) and TP53 (0.871). Through combination of the two markers (TP53 wild‑type pattern and AGR3‑positive expression), the accuracy of differential diagnosis was up to 93.1%. These findings provide compelling evidence that differential diagnosis of HGSC and LGSC can be improved by combined application of these two markers on the basis of conventional histopathological diagnosis.

WT1, p53 and p16 expression in the diagnosis of low- and high-grade serous ovarian carcinomas and their relation to prognosis

Objective

To evaluate the diagnostic and prognostic value of the immunohistochemical expression of WT1, p53 and p16 in low- (LGSOCs) and high-grade serous ovarian carcinomas (HGSOCs).

Results

HGSOC had a significantly higher proportion of advanced stage disease, higher CA125 levels, higher proportion of post-surgery residual disease and higher recurrence or disease progression. WT1 was expressed in 71.4% of LGSOCs and in 57.1% of HGSOCs (p = 0.32). Focal and/or complete absence of p53 expression with negative p16 expression was found in 90.5% of LGSOCs, in contrast to the 88.1% of HGSOCs with diffuse or complete absence of p53 expression with positive p16 expression (<0.001). The IHC p53/p16 index and the morphological classification were closely matched (k = 0.68). In the univariate analysis, FIGO stage, post-surgery residual disease and histological grade were significantly associated with progression-free survival (PFS) and overall survival (OS). The IHC p53/p16 index was associated only with PFS. WT1 was not associated with PFS or OS. According to the multivariate analysis, advanced FIGO stage and presence of post-surgery residual disease remained independent prognostic factors for worst PFS, however these features had only a trend association with OS.

Methods

21 LGSOC and 85 HGSOC stage I-IV cases were included. The morphological classification was assessed according to the World Health Organization (WHO) criteria. Immunohistochemistry (IHC) was performed in tissue microarray slides. IHC p53/p16 index was compared with the morphological classification.

Conclusions

The IHC p53/p16 index was a good marker for the differentiation of LGSOC and HGSOC, but the morphologic classification showed a better association with survival. FIGO stage and post-surgery residual disease remained the only independent prognostic factors for survival.

Chlamydia trachomatis, Chlamydial Heat Shock Protein 60 and Anti-Chlamydial Antibodies in Women with Epithelial Ovarian Tumors

OBJECTIVE: Chlamydia trachomatis (C. trachomatis) infection has been suggested to promote epithelial ovarian cancer (EOC) development. This study sought to explore the presence of C. trachomatis DNA and chlamydial heat shock protein 60 (chsp60) in ovarian tissue, as well as anti-chlamydial IgG antibodies in plasma, in relation to subtypes of EOC. METHODS: This cross-sectional cohort consisted of 69 women who underwent surgery due to suspected ovarian pathology. Ovarian tissue and corresponding blood samples were collected at the time of diagnosis. In ovarian tumor tissue, p53, p16, Ki67 and chsp60 were analyzed immunohistochemically, and PCR was used to detect C. trachomatis DNA. Plasma C. trachomatis IgG and cHSP60 IgG were analyzed with a commercial MIF-test and ELISA, respectively. RESULTS: Eight out of 69 women had C. trachomatis DNA in their ovarian tissue, all were invasive ovarian cancer cases (16.7% of invasive EOC). The prevalence of the chsp60 protein, C. trachomatis IgG and cHSP60 IgG in HGSC, compared to other ovarian tumors, was 56.0% vs. 37.2% P = .13, 15.4% vs. 9.3% P = .46 and 63.6% vs. 45.5% P = .33 respectively. None of the markers of C. trachomatis infection were associated with p53, p16 or Ki67. CONCLUSIONS: C. trachomatis was detected in invasive ovarian cancer, supporting a possible role in carcinogenesis of EOC. However, there were no statistically significant associations of chsp60 in ovarian tissue, or plasma anti-chlamydial IgG antibodies, with any of the subtypes of ovarian tumors.

WT1, p53 and p16 expression in the diagnosis of low- and high-grade serous ovarian carcinomas and their relation to prognosis

Objective

To evaluate the diagnostic and prognostic value of the immunohistochemical expression of WT1, p53 and p16 in low- (LGSOCs) and high-grade serous ovarian carcinomas (HGSOCs).

Results

HGSOC had a significantly higher proportion of advanced stage disease, higher CA125 levels, higher proportion of post-surgery residual disease and higher recurrence or disease progression. WT1 was expressed in 71.4% of LGSOCs and in 57.1% of HGSOCs (p = 0.32). Focal and/or complete absence of p53 expression with negative p16 expression was found in 90.5% of LGSOCs, in contrast to the 88.1% of HGSOCs with diffuse or complete absence of p53 expression with positive p16 expression (<0.001). The IHC p53/p16 index and the morphological classification were closely matched (k = 0.68). In the univariate analysis, FIGO stage, post-surgery residual disease and histological grade were significantly associated with progression-free survival (PFS) and overall survival (OS). The IHC p53/p16 index was associated only with PFS. WT1 was not associated with PFS or OS. According to the multivariate analysis, advanced FIGO stage and presence of post-surgery residual disease remained independent prognostic factors for worst PFS, however these features had only a trend association with OS.

Methods

21 LGSOC and 85 HGSOC stage I–IV cases were included. The morphological classification was assessed according to the World Health Organization (WHO) criteria. Immunohistochemistry (IHC) was performed in tissue microarray slides. IHC p53/p16 index was compared with the morphological classification.

Conclusions

The IHC p53/p16 index was a good marker for the differentiation of LGSOC and HGSOC, but the morphologic classification showed a better association with survival. FIGO stage and post-surgery residual disease remained the only independent prognostic factors for survival.

[Grading of gynecological tumors : Current aspects]

Histopathological assessment of the tumor grade and cell type is central to the management and prognosis of various gynecological malignancies. Conventional grading systems for squamous carcinomas and adenocarcinomas of the vulva, vagina and cervix are poorly defined. For endometrioid tumors of the female genital tract as well as for mucinous endometrial, ovarian and seromucinous ovarian carcinomas, the 3‑tiered FIGO grading system is recommended. For uterine neuroendocrine tumors the grading system of the gastrointestinal counterparts has been adopted. Uterine leiomyosarcomas are not graded. Endometrial stromal sarcomas are divided into low and high grades, based on cellular morphology, immunohistochemical and molecular findings. A chemotherapy response score was established for chemotherapeutically treated high-grade serous pelvic cancer. For non-epithelial ovarian malignancies, only Sertoli-Leydig cell tumors and immature teratomas are graded. At this time molecular profiling has no impact on the grading of tumors of the female genital tract.

Molecular Alterations of TP53 are a Defining Feature of Ovarian High-Grade Serous Carcinoma: A Rereview of Cases Lacking TP53 Mutations in The Cancer Genome Atlas Ovarian Study

The Cancer Genome Atlas has reported that 96% of ovarian high-grade serous carcinomas (HGSCs) have TP53 somatic mutations suggesting that mutation of this gene is a defining feature of this neoplasm. In the current study, 5 gynecologic pathologists independently evaluated hematoxylin and eosin slides of 14 available cases from The Cancer Genome Atlas classified as HGSC that lacked a TP53 mutation. The histologic diagnoses rendered by these pathologists and the accompanying molecular genetic data are the subject of this report. Only 1 case (Case 5), which contained a homozygous deletion of TP53, had unanimous interobserver agreement for a diagnosis of pure HGSC. In 1 case (Case 3), all 5 observers (100%) rendered a diagnosis of HGSC; however, 3 observers (60%) noted that the histologic features were not classic for HGSC and suggested this case may have arisen from a low-grade serous carcinoma (arisen from an alternate pathway compared with the usual HGSC). In 2 cases (Cases 4 and 12), only 3 observers (60%) in each case, respectively, interpreted it as having a component of HGSC. In the remaining 10 (71%) of tumors (Cases 1, 2, 6-11, 13, and 14), the consensus diagnosis was not HGSC, with individual diagnoses including low-grade serous carcinoma, high-grade endometrioid carcinoma, HGSC, metastatic carcinoma, clear cell carcinoma, atypical proliferative (borderline) serous tumor, and adenocarcinoma, not otherwise specified. Therefore, 13 (93%) of the tumors (Cases 1-4 and 6-14) were either not a pure HGSC or represented a diagnosis other than HGSC, all with molecular results not characteristic of HGSC. Accordingly, our review of the TP53 wild-type HGSCs reported in The Cancer Genome Atlas suggests that 100% of de novo HGSCs contain TP53 somatic mutations or deletions, with the exception of the rare HGSCs that develop from a low-grade serous tumor precursor. We, therefore, propose that lack of molecular alterations of TP53 are essentially inconsistent with the diagnosis of ovarian HGSC and that tumors diagnosed as such should be rigorously reassessed to achieve correct classification.

p14 expression differences in ovarian benign, borderline and malignant epithelial tumors

BACKGROUND

Abnormalities in tumor suppressors p14, p16 and p53 are reported in several human cancers. In ovarian epithelial carcinogenesis, p16 and p53 show higher immunohistochemical staining frequencies in malignant tumors and are associated with poor prognoses. p14 was only analyzed in carcinomas, with conflicting results. There are no reports on its expression in benign and borderline tumors. This study aims to determine p14, p16 and p53 expression frequencies in ovarian benign, borderline and malignant tumors and their associations with clinical parameters.

METHODS

A cross-sectional study utilizing immunohistochemistry was performed on paraffin-embedded ovarian epithelial tumor samples. Clinical data were collected from medical records. Fisher's exact test and the Bonferroni correction were performed for frequency associations. Survival comparisons utilized Kaplan-Meier and log rank testing. Associations were considered significant when p < 0.05.

RESULTS

p14 absent expression was associated with malignant tumors (60 % positive) (p = 0.000), while 93 % and 94 % of benign and borderline tumors, respectively, were positive. p16 was positive in 94.6 % of carcinomas, 75 % of borderline and 45.7 % of benign tumors (p = 0.000). p53 negative staining was associated with benign tumors (2.9 % positive) (p = 0.016) but no difference was observed between borderline (16.7 %) and malignant tumors (29.7 %) (p = 0.560). No associations were found between expression rates, disease-free survival times or clinical variables. Carcinoma subtypes showed no difference in expression.

CONCLUSIONS

This is the first description of p14 expression in benign and borderline tumors. It remains stable in benign and borderline tumors, while carcinomas show a significant absence of staining. This may indicate that p14 abnormalities occur later in carcinogenesis. p16 and p53 frequencies increase from benign to borderline and malignant tumors, similarly to previous reports, possibly reflecting the accumulation of inactive mutant protein. The small sample size may have prevented statistically significant survival analyses and clinical correlations. Future studies should investigate genetic abnormalities in p14 coding sequences and include all types of ovarian epithelial tumors. Bigger sample sizes may be needed for significant associations.

DEF6 expression in ovarian carcinoma correlates with poor patient survival

BACKGROUND

Increased expression of DEF6 is correlated with the malignant behavior of various cancers. Both DEF6 and p16 contribute to the regulation of cell cycle progression, and p53 plays important role in the cell cycle checkpoints. This study was designed to elucidate the prognostic significance of DEF6, p53 and p16 immunoexpressions in different histology subtypes of ovarian carcinoma.

METHODS

Immunohistochemistry results of DEF6, p53 and p16 on ovarian carcinoma were compared with histology subtypes, clinical data, overall survival (OS) and disease-free survival (DFS) by Cox regression and Kaplan-Meier analysis.

RESULTS

We studied 180 cases of ovarian carcinomas (75 high-grade serous, 41 clear cell, 36 mucinous and 28 endometrioid), including 109 FIGO stage I-II cases and 71 FIGO stage III-IV cases. Ovarian carcinomas positive for both DEF6 and p16 expression were associated with the worst OS (P = 0.027) and DFS (P = 0.023), whereas those negative for both DEF6 and p16 had the best OS and DFS. Aberrant p53 expression combined with positive DEF6 was associated with worst OS (P = 0.031) and DFS (P = 0.028). Kaplan-Meier analysis showed that significantly shorter survival rates were seen in patients with high expressions of DEF6 (P = 0.008) and p16 (P = 0.022). Patients with aberrant p53 expression in high-grade serous carcinoma (P = 0.012) and patients with high DEF6 expression in clear cell carcinoma (P = 0.001) were also associated with shorter overall survival. In univariate analysis, FIGO stage, DEF6 and p16 were associated with poor prognosis. DEF6 expression was the only independent prognostic factor correlated with shorted OS (HR 2.115; P = 0.025) and DFS (HR 2.248; P = 0.016) upon multivariate analysis.

CONCLUSIONS

DEF6 expression may serve as an independent prognostic factor, and interacted positively with p16 toward high tumor stage and shorter survival.

Data set for reporting of ovary, fallopian tube and primary peritoneal carcinoma: recommendations from the International Collaboration on Cancer Reporting (ICCR)

A comprehensive pathological report is essential for optimal patient management, cancer staging and prognostication. In many countries, proforma reports are used but these vary in their content. The International Collaboration on Cancer Reporting (ICCR) is an alliance formed by the Royal College of Pathologists of Australasia, the Royal College of Pathologists of the United Kingdom, the College of American Pathologists, the Canadian Partnership Against Cancer and the European Society of Pathology, with the aim of developing an evidence-based reporting data set for each cancer site. This will reduce the global burden of cancer data set development and reduplication of effort by different international institutions that commission, publish and maintain standardised cancer reporting data sets. The resultant standardisation of cancer reporting will benefit not only those countries directly involved in the collaboration but also others not in a position to develop their own data sets. We describe the development of a cancer data set by the ICCR expert panel for the reporting of primary ovarian, fallopian tube and peritoneal carcinoma and present the 'required' and 'recommended' elements to be included in the report with an explanatory commentary. This data set encompasses the recent International Federation of Obstetricians and Gynaecologists staging system for these neoplasms and the updated World Health Organisation Classification of Tumours of the Female Reproductive Organs. The data set also addresses issues about site assignment of the primary tumour in high-grade serous carcinomas and proposes a scoring system for the assessment of tumour response to neoadjuvant chemotherapy. The widespread implementation of this data set will facilitate consistent and accurate data collection, comparison of epidemiological and pathological parameters between different populations, facilitate research and hopefully will result in improved patient management.

Stathmin 1 and p16(INK4A) are sensitive adjunct biomarkers for serous tubal intraepithelial carcinoma

OBJECTIVE

To credential Stathmin 1 (STMN1) and p16(INK4A) (p16) as adjunct markers for the diagnosis of serous tubal intraepithelial carcinoma (STIC), and to compare STMN1 and p16 expression in p53-positive and p53-negative STIC and invasive high-grade serous carcinoma (HGSC).

METHODS

Immunohistochemistry (IHC) was used to examine STMN1 and p16 expression in fallopian tube specimens (n=31) containing p53-positive and p53-negative STICs, invasive HGSCs, and morphologically normal FTE (fallopian tube epithelium). STMN1 and p16 expression was scored semiquantitatively by four individuals. The semiquantitative scores were dichotomized, and reported as positive or negative. Pooled siRNA was used to knockdown p53 in a panel of cell lines derived from immortalized FTE and HGSC.

RESULTS

STMN1 and p16 were expressed in the majority of p53-positive and p53-negative STICs and concomitant invasive HGSCs, but only scattered positive cells were present in morphologically normal FTE. Both proteins were expressed consistently across multiple STICs from the same patient and in concomitant invasive HGSC. Knockdown of p53 in immortalized FTE cells and in four HGSC-derived cell lines expressing different missense p53 mutations did not affect STMN1 protein levels.

CONCLUSIONS

This study demonstrates that STMN1 and p16 are sensitive and specific adjunct biomarkers that, when used with p53 and Ki-67, improve the diagnostic accuracy of STIC. The addition of STMN1 and p16 helps to compensate for practical limitations of p53 and Ki-67 that complicate the diagnosis in up to one third of STICs.

P16(INK⁴a) overexpression is associated with CDKN2A mutation and worse prognosis in HPV-negative laryngeal squamous cell carcinomas

We studied the expression of p16(INK4a) in a series of HPV-negative laryngeal squamous cell carcinomas and assessed its association with prognosis. Forty-five patients with laryngeal carcinoma were included in the study. Clinicopathological features and prognosis were reviewed. p16(INK4a) protein expression was analysed through immunohistochemistry. We analysed messenger RNA (mRNA) in 25 cases through quantitative reverse transcription polymerase chain reaction. HPV status was assessed by PCR using three different protocols based on MY09/11 and GP5/6 primers. Four out of 45 (9 %) cases overexpressed p16(INK4a) protein and showed a tendency to worse survival that was significant for stages I-III (log-rank p value = 0.001). Expression of p16(INK4a) mRNA was high in 12 out of 25 (48 %) cases using an arbitrary cut-off level. All tumours were HPV negative with all three detection methods. A CDKN2A mutation was found in eight cases. One case with a missense and one with a frameshift mutation showed p16(INK4a) protein expression by immunohistochemistry. Six out of seven (86 %) mutated but only 6 out of 18 (33 %) non-mutated cases presented p16(INK4a) mRNA overexpression (p = 0.03). Our findings suggest that p16(INK4a) overexpression, both at protein and mRNA levels, may reflect CDKN2A genetic alterations in HPV-negative laryngeal squamous cell carcinomas.

Retinoblastoma pathway deregulatory mechanisms determine clinical outcome in high-grade serous ovarian carcinoma

Alterations in the retinoblastoma pathway are frequent in ovarian/tubal high-grade serous cancers, but the mechanism of deregulation and the impact on patient outcome are poorly understood. A cohort of 334 high-grade serous carcinomas was studied by immunohistochemical analysis of RB1, p16, cyclin D1, cyclin E1, and Ki67. Additional detailed analyses including RB1 allelic deletion (n=42), mutation (n=75), methylation (n=31), and SNP array analyses (n=75) were performed on cases with clinical parameters, including age, debulking status, treatment, and clinical outcome. p16/RB1 expression results yielded three distinct clinically relevant subgroups upon multivariable analysis controlling for stage, debulking status, and treatment types: p16 homogeneous/RB1+ with the shortest progression-free survival (median 15 months (95% CI: 13-18); P=0.016) compared with the p16 heterogeneous/RB1+ subgroup (median 22 months (95% CI: 16-32)) and the p16 homogeneous/RB1- subgroup (median 20 months (95% CI: 15-24)). Patients in the p16 homo/RB1- subgroup showed a significant increase in overall survival (>60 months; P=0.013), which suggests an increase in sensitivity to cytotoxic agents. Analyses of Rb pathway mechanistic differences among these groups revealed frequent RB1 genomic alterations such as RB1 allelic loss and/or large spanning deletions (83%) in the p16 homo/RB1- subgroups, also indicating that RB1 deletions are frequent in high-grade serous carcinoma. CCNE1 gene gains/amplifications were frequent in the p16 homogeneous/RB1+ subgroup (68%) and cyclin D1 protein overexpression was predominantly characteristic of the p16 heterogeneous/RB1+ subgroup. These subcategories occur early in tumor progression and are seen with similar frequency in the cancer precursor lesion, serous tubal intra-epithelial carcinoma. Overall, this study uniquely identifies multiple non-synonymous mechanisms of retinoblastoma pathway deregulation that correlate with significantly different clinical outcomes. Furthermore, deregulations identified in precursor lesions suggest a key role of this pathway in serous tumor development. Recognition of these categories may identify patients with increased sensitivity to chemotherapy and new opportunities for novel therapeutics.

Genetic alteration and immunohistochemical staining patterns of ovarian high-grade serous adenocarcinoma with special emphasis on p53 immnnostaining pattern

We evaluated p53, KRAS, BRAF and CTNNB1 mutation and p53, WT1, p16 and beta-catenin expression in 31 ovarian high-grade serous adenocarcinoma. Twenty-five (80.6%) tumors contained functional mutations of p53; three frameshift, four nonsense and 19 missense mutations. None of the tumors showed KRAS, BRAF or CTNNB1 mutation. In all 18 tumors with missense mutations, ≥60% of tumor cells were strongly positive for p53 immunostaining whereas all tumors with frameshift or nonsense mutations were completely negative. Missense mutation was correlated with diffuse and strong imunoreaction and frameshift/nonsense mutation was correlated with completely negative immunoreaction (P = 0.000). Tumors with wild-type p53 revealed a wide range of immunostaining patterns. In 27 (87.1%) and 18 (58.1%) tumors, ≥50% of tumor cells were moderate to strongly positive for WT1 and p16, respectively. A considerable intratumoral heterogeneity for p16 expression was present. None of the tumors demonstrated nuclear beta-catenin expression. p53 mutations appear to be a powerful molecular marker for ovarian high-grade serous adenocarcinoma. Using p53 with an appropriate interpretation criteria together with WT1, p16 and beta-catenin, most of the high-grade serous adenocarcinoma could be distinguished from other ovarian tumors.

Ovarian carcinoma histotype determination is highly reproducible, and is improved through the use of immunohistochemistry

AIMS

To assess the variation in ovarian carcinoma type diagnosis among gynaecological pathologists from Nordic countries, and whether a rationally designed panel of immunohistochemical markers could improve diagnostic reproducibility.

METHODS AND RESULTS

Eight pathologists from four countries (Sweden, Denmark, Norway, and Finland) received an educational lecture on the diagnosis of ovarian carcinoma type. All tumour-containing slides from 54 ovarian carcinoma cases were independently reviewed by the participants, who: (i) determined type purely on the basis of histology; (ii) indicated whether they would apply immunohistochemistry in their routine practice; and (iii) determined type after reviewing the staining results. The results for six markers (WT1, p53, p16, HNF-1β, ARID1A, and progesterone receptor) were determined for all 54 cases, by staining of a tissue microarray. The median concordance with central review diagnosis was 86%, and significantly improved to 90% with the incorporation of immunostaining results (P = 0.0002). The median interobserver agreement was 78%, and significantly improved to 85% with the incorporation of immunostaining results (P = 0.0002).

CONCLUSIONS

Use of the immunostaining results significantly improved both diagnostic accuracy and interobserver agreement. These results indicate that ovarian carcinoma type can be reliably diagnosed by pathologists from different countries, and also demonstrate that immunohistochemistry has an important role in improving diagnostic accuracy and agreement between pathologists.

The diagnostic utility of TP53 and CDKN2A to distinguish ovarian high-grade serous carcinoma from low-grade serous ovarian tumors

Low-grade serous carcinomas and serous borderline tumors, combined herein and referred to as low-grade serous tumors, show distinct molecular alterations and clinical behaviors compared with high-grade serous carcinomas. The discrimination between low-grade serous tumors and high-grade serous carcinomas can be challenging on small tissue samples, such as cell blocks of paracentesis fluid or biopsies from omental disease. The purpose of this study was to test the ability of TP53 and CDKN2A immunohistochemistry to distinguish between high-grade serous carcinomas and low-grade serous tumors on small tissue samples. Tissue microarrays containing 582 high-grade serous carcinomas, 45 low-grade serous carcinomas, and 49 serous borderline tumors, confirmed by contemporary histopathological review, were stained for TP53 and CDKN2A (DO7 and E6H4 antibody clones, respectively). TP53 was scored as completely absent, wild-type pattern or overexpressed (>60%), and CDKN2A was scored as either negative/patchy (<90%) or block expression (>90%). The combination of the two markers, ie, the TP53 wild-type pattern and CDKN2A patchy expression, had sensitivity for low-grade serous tumors of 89%, a specificity of 93%, a positive predictive value of 68%, and a negative predictive value of 98%. These markers can, therefore, be used on small biopsies/cell blocks to refute a diagnosis of low-grade serous tumors. These findings may inform emerging neoadjuvant therapeutic strategies in advanced ovarian cancers and may be crucial for future clinical trials on molecular-based therapies.

Differentiating rectal carcinoma by an immunohistological analysis of carcinomas of pelvic organs based on the NCBI Literature Survey and the Human Protein Atlas database

The treatments and prognoses of pelvic organ carcinomas differ, depending on whether the primary tumor originated in the rectum, urinary bladder, prostate, ovary, or uterus; therefore, it is essential to diagnose pathologically the primary origin and stages of these tumors. To establish the panels of immunohistochemical markers for differential diagnosis, we reviewed 91 of the NCBI articles on these topics and found that the results correlated closely with those of the public protein database, the Human Protein Atlas. The results revealed the panels of immunohistochemical markers for the differential diagnosis of rectal adenocarcinoma, in which [+] designates positivity in rectal adenocarcinoma and [-] designates negativity in rectal adenocarcinoma: from bladder adenocarcinoma, CDX2[+], VIL1[+], KRT7[-], THBD[-] and UPK3A[-]; from prostate adenocarcinoma, CDX2[+], VIL1[+], CEACAM5[+], KLK3(PSA)[-], ACPP(PAP)[-] and SLC45A3(prostein)[-]; and from ovarian mucinous adenocarcinoma, CEACAM5[+], VIL1[+], CDX2[+], KRT7[-] and MUC5AC[-]. The panels of markers distinguishing ovarian serous adenocarcinoma, cervical carcinoma, and endometrial adenocarcinoma were also represented. Such a comprehensive review on the differential diagnosis of carcinomas of pelvic organs has not been reported before. Thus, much information has been accumulated in public databases to provide an invaluable resource for clinicians and researchers.

Morphological subtypes of ovarian carcinoma: a review with emphasis on new developments and pathogenesis

Ovarian carcinomas comprise a heterogeneous group of neoplasms, the four most common subtypes being serous, endometrioid, clear cell and mucinous. In recent years, our understanding of the underlying pathogenesis and initiating molecular events in the different tumour subtypes has greatly increased, and although ovarian carcinoma is often considered clinically as one disease, there is now a much greater realisation that the various subtypes have a different natural behaviour and prognosis. At present, adjuvant therapy is mainly dependent upon tumour stage and grade rather than type; however, this is likely to change in the future with the development of new chemotherapeutic agents and targeted therapies and clinical trials are necessary to evaluate the efficacy of different agents in clear cell, mucinous and low grade serous carcinomas, neoplasms which are considered relatively resistant to traditional chemotherapeutic regimes. In this review, the major subtypes of ovarian carcinoma are discussed. It is now firmly established that there are two distinct types of ovarian serous carcinoma, low grade and high grade, the former being much less common and arising in many cases from a serous borderline tumour. Low grade and high grade serous carcinoma represent two distinct tumour types with a different underlying pathogenesis rather than low grade and high grade variants of the same neoplasm. Both are usually advanced stage (stage III or IV) at diagnosis. B-raf and k-ras mutations are important molecular events in low grade serous carcinomas while high grade serous carcinomas are almost always associated with TP53 mutation. There is now emerging and compelling evidence that many high grade serous carcinomas (by far the most common subtype of ovarian carcinoma) actually arise from the epithelium of the distal fallopian tube. Future studies regarding the initiating molecular events in the development of this aggressive neoplasm should concentrate on this site. Primary ovarian mucinous carcinomas are uncommon, almost always unilateral and stage I, and largely of so-called intestinal or enteric type. Most arise in a stepwise manner from a pre-existing mucinous cystadenoma and mucinous borderline tumour. Endometrioid and clear cell carcinomas typically present as low stage neoplasms and in many, or most, cases arise from endometriosis; the former are usually well differentiated and there is now evidence that the majority of neoplasms reported in the past as high grade endometrioid carcinoma are of serous type. WT1 is useful in this regard since it is a relatively specific marker of a serous phenotype. It is recommended that different subtypes of ovarian carcinoma are graded using different systems rather than employing a universal grading system.

WT1 expression in the female genital tract

The Wilms tumor gene 1 (WT1) has been reported in normal tissues and many neoplasms of the female genital tract. This review discusses WT1 expression in the female genital tract and its potential utility in the differential diagnosis of neoplasms that occur at this location. WT1 is of value in the differential diagnosis of synchronous serous carcinomas arising in the ovary/fallopian tube/peritoneum and endometrium, as strong WT1 positivity in both tumors points toward an extrauterine origin. In addition, WT1 can be used to distinguish sex cord stromal tumors (WT1 positive) from endometrioid carcinomas (OECs). WT1 expression is not helpful in the differential diagnosis of ovarian serous carcinomas (OSCs) and transitional carcinomas, as both are typically positive and has limited value in the distinction of serous tumors arising in the ovary/fallopian tube/peritoneum from mesotheliomas. WT1 is also not helpful to differentiate small cell carcinoma of hypercalcemic type from juvenile granulosa cell tumor, a common diagnostic problem. Intra-abdominal desmoplastic round cell tumor reacts to WT1 (C-terminal) in contrast to all other tumors discussed which helps to separate this rare tumor from most other small round cell tumors that may involve, primarily or secondarily, the ovary with the exception of small cell carcinoma of hypercalcemic type that typically reacts with the N-terminal of WT1.

Loss of p16INK4A expression in low-grade ovarian serous carcinomas

According to a tumor progression model, low-grade ovarian serous carcinomas may evolve from serous borderline tumors or micropapillary tumors. We sought to investigate the role of and associations between BRAF mutational status, extracellular signal regulated kinase activation, and p16(INK4A) expression in various types of ovarian serous tumors. We analyzed 29 typical ovarian serous borderline tumors, 8 micropapillary tumors, 4 low-grade invasive ovarian serous carcinomas, and 24 high-grade invasive ovarian serous carcinomas for the BRAF mutational status at codon 600; in addition, expression levels of the downstream signaling protein extracellular signal regulated kinase and the p16(INK4A) tumor suppressor protein were assessed by immunohistochemistry. There was a decline in p16(INK4A) expression from serous borderline tumors to micropapillary tumors with almost complete loss in low-grade invasive carcinomas. High-grade carcinomas had a variable p16(INK4A) expression pattern. We found a T1799A BRAF mutation in 12 typical serous borderline tumors (41%) and 1 micropapillary tumor (12.5%). No mutations were found in the low-grade and high-grade invasive carcinomas (0%). Among the typical borderline tumors, cases with BRAF mutations tended to have stronger p16(INK4A) expression compared with cases with wild-type BRAF. No other correlations were identified between the BRAF mutational status and expression levels of the analyzed proteins. Loss of p16(INK4A) expression may be a pathogenetic factor in the progression from serous borderline tumors to low-grade invasive carcinomas. The divergent molecular profiles support the theory that high-grade carcinomas are unrelated to serous borderline tumors or low-grade carcinomas.

Calculator for ovarian carcinoma subtype prediction

With the emerging evidence that the five major ovarian carcinoma subtypes (high-grade serous, clear cell, endometrioid, mucinous, and low-grade serous) are distinct disease entities, management of ovarian carcinoma will become subtype specific in the future. In an effort to improve diagnostic accuracy, we set out to determine if an immunohistochemical panel of molecular markers could reproduce consensus subtype assignment. Immunohistochemical expression of 22 biomarkers were examined on tissue microarrays constructed from 322 archival ovarian carcinoma samples from the British Columbia Cancer Agency archives, for the period between 1984 and 2000, and an independent set of 242 cases of ovarian carcinoma from the Gynaecologic Tissue Bank at Vancouver General Hospital from 2001 to 2008. Nominal logistic regression was used to produce a subtype prediction model for each of these sets of cases. These models were then cross-validated against the other cohort, and then both models were further validated in an independent cohort of 81 ovarian carcinoma samples from five different centers. Starting with data for 22 markers, full model fit, backwards, nominal logistic regression identified the same nine markers (CDKN2A, DKK1, HNF1B, MDM2, PGR, TFF3, TP53, VIM, WT1) as being most predictive of ovarian carcinoma subtype in both the archival and tumor bank cohorts. These models were able to predict subtype in the respective cohort in which they were developed with a high degree of sensitivity and specificity (κ statistics of 0.88±0.02 and 0.86±0.04, respectively). When the models were cross-validated (ie using the model developed in one case series to predict subtype in the other series), the prediction equation's performances were reduced (κ statistics of 0.70±0.04 and 0.61±0.04, respectively) due to differences in frequency of expression of some biomarkers in the two case series. Both models were then validated on the independent series of 81 cases, with very good to excellent ability to predict subtype (κ=0.85±0.06 and 0.78±0.07, respectively). A nine-marker immunohistochemical maker panel can be used to objectively support classification into one of the five major subtypes of ovarian carcinoma.

Metastatic Neoplasms Involving the Ovary

In this review, ovarian metastatic carcinomas from various sites, as well as other neoplasms secondarily involving the ovary, are discussed. As well as describing the morphology, the value of immunohistochemistry in distinguishing between primary and metastatic neoplasms in the ovary is discussed. While immunohistochemistry has a valuable role to play and is paramount in some cases, the results should be interpreted with caution and with regard to the clinical picture and gross and microscopic pathologic findings.

High-Grade Serous Carcinoma Involving Fallopian Tube, Ovary and Peritoneum

The focus of this review is high-grade serous carcinoma (HGSC); for the purposes of this review, the term "pelvic SC" is used for HGSC that could be considered, based on historical definitions, to have arisen from ovary, fallopian tube, or peritoneum. These assignments of primary site are arbitrary and there is evidence that the distal fallopian tube is the site of origin of many pelvic HGSCs. The diagnosis of HGSC can be made readily based on routine histomorphologic examination in most cases; however, a variety of neoplasms can resemble HGSC. Thus, we review the key features of pelvic SC, current concepts of its pathogenesis, histopathological diagnostic criteria, discuss differential diagnosis, and review diagnostic ancillary studies that can be used in practice.

p16 Immunoreactivity in unusual types of cervical adenocarcinoma does not reflect human papillomavirus infection

AIMS

The association between human papillomavirus (HPV) and cervical carcinoma is well known, with HPV being identifiable in almost all cervical squamous carcinomas and most adenocarcinomas. However, the prevalence of HPV in unusual morphological types of cervical adenocarcinoma has not been investigated extensively. The aim was to determine HPV status in a series of primary cervical adenocarcinomas, enriched for unusual morphological types. The relationship between HPV and p16 immunoreactivity in these neoplasms was also investigated, as it is generally assumed that in cervical neoplasms diffuse p16 expression is predictive of the presence of high-risk HPV.

METHODS AND RESULTS

Sixty-three cervical adenocarcinomas, comprising those of usual type (n = 43), minimal deviation type (n = 4), gastric type (n = 3), intestinal type (n = 3), mesonephric type (n = 3), clear cell type (n = 4), serous type (n = 2) and hepatoid type (n = 1) underwent linear array HPV genotyping and immunohistochemistry for p16. Overall, HPV was identified in 32 of 56 cases (57%) in which sufficient DNA was present for analysis. The most common HPV types were 16 and 18, with these being identified in 20 and 18 cases, respectively, either alone or in combination. Seventy-eight per cent of usual-type adenocarcinomas were HPV-positive, as was the single serous carcinoma in which there was sufficient DNA for analysis. In contrast, all minimal deviation adenocarcinomas and those of gastric, intestinal, mesonephric and clear cell types were HPV-negative, as was the single hepatoid carcinoma. All usual-type adenocarcinomas exhibited p16 immunoreactivity (diffuse staining in all but one case), as did 11 of 20 of those of unusual morphological type (five focal, six diffuse).

CONCLUSIONS

Most, but not all, cervical adenocarcinomas of usual type contain HPV, but those of unusual morphological type are almost always HPV-negative. This has implications for the efficacy of HPV vaccination in the prevention of cervical adenocarcinoma. A significant proportion of cervical adenocarcinomas are p16-positive in the absence of HPV, illustrating that in these neoplasms diffuse p16 immunoreactivity is not a reliable surrogate marker of the presence of high-risk HPV.

An immunohistochemical study of cervical neuroendocrine carcinomas: Neoplasms that are commonly TTF1 positive and which may express CK20 and P63

Cervical small cell neuroendocrine carcinoma (SCNEC) and large cell neuroendocrine carcinoma (LCNEC) are uncommon but highly aggressive neoplasms. From a diagnostic point of view, there may be problems both in distinguishing these from other neoplasms and in confirming a cervical origin. This is important as management is critically dependent on the correct histologic diagnosis. We undertook a detailed immunohistochemical analysis of a relatively large series of primary cervical SCNEC (n=13) and LCNEC (n=8). Cases were stained with AE1/3, chromogranin, CD56, synaptophysin, PGP9.5, TTF1, p16, p63, CK7, CK20, neurofilament, and CD99. CK20 and neurofilament staining was undertaken to investigate whether some of these neoplasms might exhibit a Merkel cell immunophenotype and CD99 staining to assess whether there is immunohistochemical overlap with neoplasms in the Ewing family of tumors (EFT). For all markers, staining was classified as negative, 1+ (<10% cells immunoreactive), 2+ (10 to 50% cells immunoreactive), or 3+ (>50% cells immunoreactive). Eleven and 6 SCNEC and LCNEC, respectively were positive with AE1/3. Chromogranin, CD56, synaptophysin, and PGP9.5 were positive in 11, 19, 19, and 9 cases, respectively. Altogether 15 cases (71%) (11 SCNEC, 4 LCNEC) exhibited nuclear positivity, often diffuse, with TTF1. All but 1 case was diffusely positive with p16. p63 was positive in 9 cases, including 5 with diffuse nuclear immunoreactivity. Ten and 4 neoplasms were positive with CK7 and CK20, respectively. Neurofilament was positive in 7 tumors. The 4 neoplasms that were CK20 positive were stained with the monoclonal antibody CM2B4, generated against an antigenic epitope on the Merkel cell polyomavirus T antigen; all were negative. CD99 was positive in 6 cases. In 2 cases, adjacent foci of adenocarcinoma in situ (AIS) contained scattered individual chromogranin positive cells, raising the possibility that some cervical neuroendocrine carcinomas arise from neuroendocrine cells in AIS. Four of 13 cases of pure AIS also contained scattered chromogranin positive cells. Our results illustrate that a proportion of cervical neuroendocrine carcinomas are negative with broad spectrum cytokeratins and some of the commonly used neuroendocrine markers. TTF1 positivity is extremely common and may be a useful marker of a neuroendocrine carcinoma. It is of no value in exclusion of a pulmonary primary. p16 is almost always positive in cervical neuroendocrine carcinomas, possibly owing to an association with oncogenic human papillomavirus, although other mechanisms of expression are also possible. Cervical neuroendocrine carcinomas may be p63 positive, illustrating that this marker is not specific for squamous differentiation. CK20 and neurofilament positivity in some cervical neuroendocrine carcinomas is in keeping with a Merkel cell immunophenotype, similar to that described in SCNECs in other organs. However, the absence of staining with CM2B4 argues against a true Merkel cell tumor. CD99 staining in a cervical neuroendocrine carcinoma should not result in misdiagnosis as a neoplasm in the Ewing family of tumors.

Protease inhibitor SERPINA1 expression in epithelial ovarian cancer

Epithelial ovarian cancer is the most lethal gynecologic cancer with a 5 years survival rate of 30-40% in patients diagnosed with high-grade invasive disease (TOV). This is in stark contrast to the 95% 5 years survival rate in ovarian cancer patients diagnosed with low malignant potential (LMP) disease. The progression from localized tumor to invasive metastasis involves matrix proteolysis. Protease inhibitors are thought to play a key role by limiting this process. Using the Affymetrix HG-U133A GeneChip array, we have studied all serine protease inhibitors and found several serpin family members that are differentially expressed between LMP and TOV serous tumors. SERPINA1 was selected for further study due to its high expression in the majority of LMP tumors and its low expression in TOV tumors; observations that were also validated by quantitative-PCR (Q-PCR). To study the effects of its over expression on different tumorigenic parameters, SERPINA1 was cloned in the pcDNA3.1+ plasmid which was subsequently used to derive stable clones from two invasive ovarian cancer cell lines, TOV-112D and TOV-1946. We found no effect of SERPINA1 over expression on tumor growth in SCID mice although cell migration and invasion were affected in in vitro assays. There was also no association between patient survival and SERPINA1 immunostaining, however, SERPINA1 localization was different in LMP (nuclear) and TOV (cytoplasmic) tumors. SERPINA1 remains an interesting candidate since protein homeostasis, regulated by proteases and their inhibitors, should be studied holistically in order to assess their full impact in tumor progression.

PAX2 expression in low malignant potential ovarian tumors and low-grade ovarian serous carcinomas

Ovarian tumors of low malignant potential and low-grade ovarian serous carcinomas are thought to represent different stages on a tumorigenic continuum and to develop along pathways distinct from high-grade ovarian serous carcinoma. We performed gene expression profiling on three normal human ovarian surface epithelia samples, and 10 low-grade and 10 high-grade ovarian serous carcinomas. Analysis of gene expression profiles of these samples has identified 80 genes upregulated and 232 genes downregulated in low-grade ovarian serous carcinomas. PAX2 was found to be one of the most upregulated genes in low-grade ovarian serous carcinoma. The upregulation of PAX2 was validated by real-time quantitative RT-PCR, western blot and immunohistochemical analyses. Real-time RT-PCR showed a statistically significant difference in PAX2 mRNA expression (expressed as fold change in comparison to normal human ovarian surface epithelia) among ovarian tumors of low malignant potential (1837.38, N=8), low-grade (183.12, N=17), and high-grade (3.72, N=23) carcinoma samples (P=0.015). Western blot analysis revealed strong PAX2 expression in ovarian tumors of low malignant potential (67%, N=3) and low-grade carcinoma samples (50%, N=10) but no PAX2 protein expression in high-grade carcinomas (0%, N=10). Using immunohistochemistry, tumors of low malignant potential (59%, N=17) and low-grade carcinoma (63%, N=16) samples expressed significantly stronger nuclear staining than high-grade ovarian carcinoma samples (9.1%, N=263). Furthermore, consistent with earlier immunohistochemical findings, PAX2 expression was expressed in the epithelial cells of fallopian tubes but not in normal ovarian surface epithelial cells. Our findings further support the two-tiered hypothesis that tumors of low malignant potential and low-grade ovarian serous carcinoma are on a continuum and are distinct from high-grade ovarian carcinomas. In addition, the absence of PAX2 expression in normal ovarian epithelia but expression in fallopian tube fimbria and ciliated epithelial inclusions would suggest the potential development of tumors of low malignant potential and of low-grade ovarian serous carcinomas from secondary Müllerian structures.

Ovarian low-grade and high-grade serous carcinoma: pathogenesis, clinicopathologic and molecular biologic features, and diagnostic problems

Ovarian serous carcinomas have been graded using various systems. Recently, a 2-tier system in which tumors are subdivided into low grade and high grade has been proposed. This approach is simplistic, reproducible, and based on biologic evidence indicating that both tumors develop via different pathways. Low-grade serous carcinomas exhibit low-grade nuclei with infrequent mitotic figures. They evolve from adenofibromas or borderline tumors, have frequent mutations of the KRAS, BRAF, or ERBB2 genes, and lack TP53 mutations (Type I pathway). The progression to invasive carcinoma is a slow step-wise process. Low-grade tumors are indolent and have better outcome than high-grade tumors. In contrast, high-grade serous carcinomas have high-grade nuclei and numerous mitotic figures. Identification of a precursor lesion in the ovary has been elusive and therefore the origin of ovarian carcinoma has been described as de novo. More recently, studies have suggested that a proportion seem to originate from intraepithelial carcinoma in the fallopian tube. The development of these tumors is rapid (Type II pathway). Most are characterized by TP53 mutations and lack mutations of KRAS, BRAF, or ERBB2. Although both types of serous carcinomas evolve along different pathways, rare high-grade serous carcinomas seem to arise through the Type I pathway. Immunohistochemical stains for p53, p16, and Ki-67 for distinction of low-grade from high-grade tumors are of limited value but can be helpful in selected instances. This review provides an update on the pathogenesis and clinicopathologic features of these 2 types of serous carcinomas and addresses some of the diagnostic problems that are encountered in routine practice.