Mutation of FOXL2 in granulosa-cell tumors of the ovary.

BACKGROUND: Granulosa-cell tumors (GCTs) are the most common type of malignant ovarian sex cord-stromal tumor (SCST). The pathogenesis of these tumors is unknown. Moreover, their histopathological diagnosis can be challenging, and there is no curative treatment beyond surgery. METHODS: We analyzed four adult-type GCTs using whole-transcriptome paired-end RNA sequencing. We identified putative GCT-specific mutations that were present in at least three of these samples but were absent from the transcriptomes of 11 epithelial ovarian tumors, published human genomes, and databases of single-nucleotide polymorphisms. We confirmed these variants by direct sequencing of complementary DNA and genomic DNA. We then analyzed additional tumors and matched normal genomic DNA, using a combination of direct sequencing, analyses of restriction-fragment-length polymorphisms, and TaqMan assays. RESULTS: All four index GCTs had a missense point mutation, 402C-->G (C134W), in FOXL2, a gene encoding a transcription factor known to be critical for granulosa-cell development. The FOXL2 mutation was present in 86 of 89 additional adult-type GCTs (97%), in 3 of 14 thecomas (21%), and in 1 of 10 juvenile-type GCTs (10%). The mutation was absent in 49 SCSTs of other types and in 329 unrelated ovarian or breast tumors. CONCLUSIONS: Whole-transcriptome sequencing of four GCTs identified a single, recurrent somatic mutation (402C-->G) in FOXL2 that was present in almost all morphologically identified adult-type GCTs. Mutant FOXL2 is a potential driver in the pathogenesis of adult-type GCTs.

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.

Progesterone receptor is a significant factor associated with clinical outcomes and effect of adjuvant tamoxifen therapy in breast cancer patients.

Estrogen receptor status in breast cancer is associated with response to hormonal therapy and clinical outcome. The additional value of progesterone receptor (PR) has remained controversial. We examine the value of PR for prognosis and response to tamoxifen on a population-based series of 4,046 invasive early stage breast cancer patients. Clinical information for age at diagnosis, stage, pathology, treatment and outcome was assembled for the study cohort; the median follow-up was 12.4 years. PR status was determined by immunohistochemistry using a rabbit monoclonal antibody on tissue microarrays built from breast tumor surgical excisions. Survival analyses, Kaplan-Meier functions and Cox proportional hazards regression models were applied to assess the associations between PR and breast cancer specific survival. Progesterone receptor was positive in 51% of all cases and 67% of estrogen receptor positive (ER+) cases. Survival analyses for both the whole cohort and ER+ cases given tamoxifen therapy showed that patients with PR+ tumors had 24% higher relative probability for breast cancer specific survival as compared to PR- patients, adjusted for ER, HER2, age at diagnosis, grade, tumor size, lymph node status and lymphovascular invasion covariates. Higher PR expression showed stronger association with patient survival. Log-likelihood ratio tests of multivariate Cox proportional hazards regression models demonstrated that PR was an independent statistically significant factor for breast cancer specific survival in both the whole cohort and among ER+ cases treated with tamoxifen. PR adds significant prognostic value in breast cancer beyond that obtained with estrogen receptor alone.

Primary ovarian mucinous carcinoma of intestinal type: significance of pattern of invasion and immunohistochemical expression profile in a series of 31 cases.

Primary ovarian mucinous carcinomas of the intestinal type are uncommon and earlier reports have included cases diagnosed according to older, less stringent, criteria (which would now be considered borderline tumors) and variable numbers of cases of metastatic adenocarcinoma. This study was conducted to identify all cases of primary mucinous carcinoma of the ovary in a population-based registry, diagnosed according to WHO 2003 criteria, and to characterize their histologic features, immunohistochemical expression profile, and outcome. Thirty-one cases of primary ovarian mucinous carcinoma were included in this study. Immunostaining for 33 markers was performed. Mean age of the patients was 55.4+/-13.5 years. Thirty tumors were stage I or II at presentation. Twenty-six of 31 (83.9%) tumors had expansile stromal invasion, 4 of 31 (12.9%) showed destructive invasion, and 1 of 31 (3.2%) had anaplastic carcinoma in a mural nodule. All cases with destructive invasion showed grade 3 nuclear atypia whereas only 3 of 26 (11.5%) cases with expansile invasion had grade 3 nuclear atypia (P=0.0003). At follow-up, 6 of 26 patients (23.1%) with tumors showing expansile invasion experienced a recurrence, compared with 1 of 4 patients (25%) with destructive invasion and the single patient (100%) with anaplastic carcinoma. There was CK7 positivity in 26 of 31 cases (86.7%), and CK20 and Cdx-2 were each positive in 33.3% of cases. D2-40, calretinin, mesothelin, CA-125, Pax-8, TTF, and WT1 were completely negative in all cases. NHERF1 staining was present in 19 of 26 cases (73%) and its expression was associated with poor prognosis (P=0.05). Our findings support current diagnostic criteria for primary ovarian mucinous carcinoma, that is, the presence of expansile invasion, in the absence of destructive invasion, warrants a diagnosis of carcinoma. A large majority of mucinous carcinomas show only an expansile pattern of invasion and are confined to the pelvis at diagnosis.

IGF2BP3 (IMP3) expression is a marker of unfavorable prognosis in ovarian carcinoma of clear cell subtype.

Clear cell carcinoma is an uncommon subtype of ovarian carcinoma, accounting for 10% of cases. Clear cell carcinoma typically presents with stage I or II disease, and in this setting prognostic markers could aid in management decisions, in particular the decision to treat with adjuvant chemotherapy. We tested whether expression of insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3, also known as IMP3) can serve as a new biomarker to predict outcome for patients with clear cell carcinoma and other subtypes of ovarian carcinoma. The expression of IGF2BP3 was evaluated by immunohistochemistry in 475 ovarian carcinomas of different subtypes and correlated with disease-specific survival. IGF2BP3 antibody specificity was validated by correlation of IGF2BP3 protein with mRNA expression level in a series of 35 ovarian carcinomas (r=0.849, P<0.0001). IGF2BP3 protein expression was an independent marker of reduced disease-specific survival (risk ratio 2.9, 95% confidence interval 1.4-5.8) in the clear cell subtype (N=128), but not in high-grade serous (N=198) or endometrioid (N=121) carcinomas. The prognostic significance of IGF2BP3 expression for reduced disease-specific survival (risk ratio 2.6, 95% confidence interval 1.3-5.0) was confirmed in an independent series of cases (N=150) from three different centers in North America. We conclude that IGF2BP3 is the first biomarker of prognostic significance in ovarian clear cell carcinoma that has been validated in an independent case series.

Ovarian carcinoma subtypes are different diseases: implications for biomarker studies.

BACKGROUND: Although it has long been appreciated that ovarian carcinoma subtypes (serous, clear cell, endometrioid, and mucinous) are associated with different natural histories, most ovarian carcinoma biomarker studies and current treatment protocols for women with this disease are not subtype specific. With the emergence of high-throughput molecular techniques, distinct pathogenetic pathways have been identified in these subtypes. We examined variation in biomarker expression rates between subtypes, and how this influences correlations between biomarker expression and stage at diagnosis or prognosis. METHODS AND FINDINGS: In this retrospective study we assessed the protein expression of 21 candidate tissue-based biomarkers (CA125, CRABP-II, EpCam, ER, F-Spondin, HE4, IGF2, K-Cadherin, Ki-67, KISS1, Matriptase, Mesothelin, MIF, MMP7, p21, p53, PAX8, PR, SLPI, TROP2, WT1) in a population-based cohort of 500 ovarian carcinomas that was collected over the period from 1984 to 2000. The expression of 20 of the 21 biomarkers differs significantly between subtypes, but does not vary across stage within each subtype. Survival analyses show that nine of the 21 biomarkers are prognostic indicators in the entire cohort but when analyzed by subtype only three remain prognostic indicators in the high-grade serous and none in the clear cell subtype. For example, tumor proliferation, as assessed by Ki-67 staining, varies markedly between different subtypes and is an unfavourable prognostic marker in the entire cohort (risk ratio [RR] 1.7, 95% confidence interval [CI] 1.2%-2.4%) but is not of prognostic significance within any subtype. Prognostic associations can even show an inverse correlation within the entire cohort, when compared to a specific subtype. For example, WT1 is more frequently expressed in high-grade serous carcinomas, an aggressive subtype, and is an unfavourable prognostic marker within the entire cohort of ovarian carcinomas (RR 1.7, 95% CI 1.2%-2.3%), but is a favourable prognostic marker within the high-grade serous subtype (RR 0.5, 95% CI 0.3%-0.8%). CONCLUSIONS: The association of biomarker expression with survival varies substantially between subtypes, and can easily be overlooked in whole cohort analyses. To avoid this effect, each subtype within a cohort should be analyzed discretely. Ovarian carcinoma subtypes are different diseases, and these differences should be reflected in clinical research study design and ultimately in the management of ovarian carcinoma.

Kisspeptin and GPR54 immunoreactivity in a cohort of 518 patients defines favourable prognosis and clear cell subtype in ovarian carcinoma.

BACKGROUND: Kisspeptins and their G-protein coupled receptor, GPR54 are required for GnRH release and have been associated with anti-metastatic tumour cell behaviour in model systems. The latter might suggest that their overexpression would be associated with a better prognosis in cancer. However, kisspeptin/GPR54 interactions (autocrine, paracrine, and/or endocrine) could also impact tumour behaviour in a negative manner. Here, for the first time, we associate the immunoreactivity of the kisspeptin/GPR54 ligand-receptor pair with favourable prognosis in a large cohort of ovarian carcinomas. METHODS: Immunohistochemical analysis for kisspeptin and GPR54 was performed on a tissue microarray (TMA) consisting of 518 early stage ovarian carcinomas, all with linked clinical outcome data. The TMA was scored using a staining intensity scale of 0 (negative), +1 (mild-moderate), and +2 (strong). Strong staining cases were considered either kisspeptin or GPR54 positive and designated as 1, while all other cases were considered negative and designated 0. All statistical analysis was conducted using two-sided tests and a p value equal to or less than 0.05 was considered significant. RESULTS: Kisspeptin and GPR54 immunoreactive cases show a favourable prognosis in univariable disease specific survival (p = 0.0023, p = 0.0092), as well as in overall survival (p = 0.0006, p = 0.0002). Furthermore, kisspeptin is an independent marker for favourable prognosis as determined by multivariable disease specific (p = 0.0046) and overall survival analysis (p = 0.0170), while GPR54 is an independent marker for overall survival only (p = 0.0303). Both kisspeptin positive and GPR54 positive cases are strongly associated with the ovarian carcinoma clear cell subtype (p < 0.0001, p < 0.0001), and GPR54 is significantly associated with favourable prognosis in overall survival within the clear cell subtype (p = 0.0102). CONCLUSION: Kisspeptin and GPR54 immunoreactivity are significantly associated with favourable prognosis in both disease specific and overall survival, as well as being significantly associated with the clear cell ovarian carcinoma subtype, thereby creating the first independent prognostic biomarkers specific for ovarian clear cell carcinomas.

An international Ki67 reproducibility study.

BACKGROUND: In breast cancer, immunohistochemical assessment of proliferation using the marker Ki67 has potential use in both research and clinical management. However, lack of consistency across laboratories has limited Ki67's value. A working group was assembled to devise a strategy to harmonize Ki67 analysis and increase scoring concordance. Toward that goal, we conducted a Ki67 reproducibility study. METHODS: Eight laboratories received 100 breast cancer cases arranged into 1-mm core tissue microarrays-one set stained by the participating laboratory and one set stained by the central laboratory, both using antibody MIB-1. Each laboratory scored Ki67 as percentage of positively stained invasive tumor cells using its own method. Six laboratories repeated scoring of 50 locally stained cases on 3 different days. Sources of variation were analyzed using random effects models with log2-transformed measurements. Reproducibility was quantified by intraclass correlation coefficient (ICC), and the approximate two-sided 95% confidence intervals (CIs) for the true intraclass correlation coefficients in these experiments were provided. RESULTS: Intralaboratory reproducibility was high (ICC = 0.94; 95% CI = 0.93 to 0.97). Interlaboratory reproducibility was only moderate (central staining: ICC = 0.71, 95% CI = 0.47 to 0.78; local staining: ICC = 0.59, 95% CI = 0.37 to 0.68). Geometric mean of Ki67 values for each laboratory across the 100 cases ranged 7.1% to 23.9% with central staining and 6.1% to 30.1% with local staining. Factors contributing to interlaboratory discordance included tumor region selection, counting method, and subjective assessment of staining positivity. Formal counting methods gave more consistent results than visual estimation. CONCLUSIONS: Substantial variability in Ki67 scoring was observed among some of the world's most experienced laboratories. Ki67 values and cutoffs for clinical decision-making cannot be transferred between laboratories without standardizing scoring methodology because analytical validity is limited.

Validation of immature adipogenic status and identification of prognostic biomarkers in myxoid liposarcoma using tissue microarrays.

Myxoid liposarcoma displays variably aggressive behavior and responds poorly to available systemic therapies. Expression profiling followed by tissue microarray validation linked to patient outcome is a powerful approach for validating biological mechanisms and identifying prognostic biomarkers. We applied these techniques to independent series of primary myxoid liposarcomas in an effort to assess markers of adipose differentiation in myxoid liposarcoma and to identify prognostic markers that can be efficiently assessed by immunohistochemistry. Candidate genes were selected based on analysis of expression profiles from 9 primary myxoid/round liposarcomas and 45 other soft tissue tumors, and by reference to publicly available data sets. Protein products were validated on an adipose neoplasm tissue microarray, including 32 myxoid liposarcomas linked to patient outcome. Results were scored visually and correlated with clinical outcome by Kaplan-Meier and Cox regression analyses. In the study, by examining expression patterns of several lipogenic regulatory gene products, an immature adipogenic status was verified in myxoid liposarcomas. We also found that expression levels of the ret proto-oncogene, insulin-like growth factor 1 receptor, and insulin-like growth factor 2 correlate with poor metastasis-free survival, supporting a role for ERK/MAPK and PI3K/AKT pathways in clinically aggressive myxoid liposarcomas.