Low-grade Serous Tumors Research Articles

Ovarian cancer: role of ultrasound in preoperative diagnosis and population screening

Ovarian cancer: role of ultrasound in preoperative diagnosis and population screening

Low-Grade Ovarian Serous Neoplasms (Low-Grade Serous Carcinoma and Serous Borderline Tumor) Associated With High-Grade Serous Carcinoma or Undifferentiated Carcinoma

Recent literature has suggested a dual pathway of ovarian serous carcinogenesis, with most serous carcinomas falling into 1 of 2 categories, low grade and high grade. These are considered to represent 2 distinct tumor types with a different underlying pathogenesis and associated with different molecular events, clinical behavior, and prognosis. Low-grade serous carcinoma is thought to evolve in many instances from a preexisting serous borderline tumor and cystadenoma. Given the distinct pathogenesis and different molecular events, it is expected that the coexistence of low-grade and high-grade serous carcinoma would be rare or may even be mutually exclusive; moreover, there are very few reported examples in the literature. We report a series of 7 cases in patients aged 34 to 78 years in whom ovarian low-grade serous carcinoma (4 cases, including 3 with associated serous borderline tumor), serous borderline tumor (2 cases), or seromucinous borderline tumor (1 case) was associated with a high-grade carcinoma, either high-grade serous (5 cases) or undifferentiated carcinoma (2 cases). The low-grade and high-grade components coexisted in the original neoplasm in 4 cases, and the high-grade component was present only in recurrence in 3 cases. In both instances, the undifferentiated carcinoma had a focal rhabdoid morphology, and alternative primary sites of tumor were excluded by a combination of clinical, radiologic, and pathologic parameters. We illustrate that low-grade serous carcinoma or serous borderline tumor ("low-grade" serous neoplasms) may rarely be associated with, and probably give rise to, a high-grade carcinoma, either high-grade serous or undifferentiated carcinoma. The coexistence of a low-grade serous neoplasm and undifferentiated carcinoma can be regarded as a form of dedifferentiation. p53 was diffusely positive in 4 of 6 high-grade carcinomas, which raises the possibility that secondary Tp53 mutation is important in high-grade transformation in some of these cases. WT1 was negative in the 2 undifferentiated carcinomas, and PAX8 was positive in 1, suggesting that the latter marker is more useful in helping to confirm a Mullerian origin in dedifferentiated low-grade serous neoplasms.

Low‐grade serous carcinomas of the ovary contain very few point mutations

It has been well established that ovarian low-grade and high-grade serous carcinomas are fundamentally different types of tumours. While the molecular genetic features of ovarian high-grade serous carcinomas are now well known, the pathogenesis of low-grade serous carcinomas, apart from the recognition of frequent somatic mutations involving KRAS and BRAF, is largely unknown. In order to comprehensively analyse somatic mutations in low-grade serous carcinomas, we applied exome sequencing to the DNA of eight samples of affinity-purified, low-grade, serous carcinomas. A remarkably small number of mutations were identified in seven of these tumours: a total of 70 somatic mutations in 64 genes. The eighth case displayed mixed serous and endometrioid features and a mutator phenotype with 783 somatic mutations, including a nonsense mutation in the mismatch repair gene, MSH2. We validated representative mutations in an additional nine low-grade serous carcinomas and 10 serous borderline tumours, the precursors of ovarian low-grade, serous carcinomas. Overall, the genes showing the most frequent mutations were BRAF and KRAS, occurring in 10 (38%) and 5 (19%) of 27 low-grade tumours, respectively. Except for a single case with a PIK3CA mutation, other mutations identified in the discovery set were not detected in the validation set of specimens. Our mutational analysis demonstrates that point mutations are much less common in low-grade serous tumours of the ovary than in other adult tumours, a finding with interesting scientific and clinical implications.

Papillary Tubal Hyperplasia

In contrast to the controversy regarding the terminology and behavior of ovarian noninvasive low-grade serous tumors [atypical proliferative serous tumor (APST) and serous borderline tumor], little attention has been directed to their origin. Similarly, until recently, proliferative lesions in the fallopian tube had not been extensively studied. The recent proposal that ovarian high-grade serous carcinomas are derived from intraepithelial carcinoma in the fallopian tube prompted us to evaluate the possible role of fallopian tube in the genesis of low-grade serous tumors. We have identified a lesion, designated "papillary tubal hyperplasia (PTH)," characterized by small rounded clusters of tubal epithelial cells and small papillae, with or without associated psammoma bodies, that are present within the tubal lumen and which are frequently associated with APSTs. Twenty-two cases in this study were selected from a population-based study in Denmark of approximately 1000 patients with low-grade ovarian serous tumors in whom implants were identified on the fallopian tube. Seven additional cases were seen recently in consultation at The Johns Hopkins Hospital (JHH). These 7 cases were not associated with an ovarian tumor. PTH was found in 20 (91%) of the 22 cases in the Danish study. On the basis of this association of PTH with APSTs with implants and the close morphologic resemblance of PTH, not only to primary ovarian APSTs but also to noninvasive epithelial implants and endosalpingiosis, we speculate that the small papillae and clusters of cells from the fallopian tube implant on ovarian and peritoneal surfaces to produce these lesions. The 7 JHH cases of PTH that were not associated with an ovarian tumor support the view that PTH is the likely precursor lesion. We propose a model for the development of ovarian and extraovarian low-grade serous proliferations (APST, noninvasive epithelial implants, and endosalpingiosis) that postulates that all of these lesions are derived from PTH, which appears to be induced by chronic inflammation. If this hypothesis is confirmed, it can be concluded that low-grade and high-grade ovarian tumors develop from tubal epithelium and involve the ovary secondarily.

Abstract A11: Loss of LKB1 is an early event in high-grade serous carcinoma

Abstract Background: LKB1 is a ubiquitously expressed serine/threonine protein kinase recently ranked sixteenth on the list of top cancer genes. Inactivating germ-line mutations in LKB1 gene on chromosome 19p13.3 found in 60–70% of patients with Peutz-Jeghers syndrome (PJS), leading to increased risk of developing cancers of epithelial origin. Loss of LKB1 protein with underlying LKB1 gene methylation previously found in high-grade breast carcinoma – low expression associated with shorter relapse-free survival. Heterozygous mutations of LKB1 and p53 genes cooperate in the acceleration of tumorigenesis in mice. High-grade serous ovarian cancer (HGSC) is rarely diagnosed at an early and potentially curable stage, effective early detection and preventative strategies are few. In a previously published microarray study, we observed that LKB1 mRNA was significantly lower in Fallopian tube cancers and HGSC. Recently the discovery of occult invasive and intraepithelial tubal carcinomas in BRCA1 mutation carriers, who are at high risk of serous cancer, undergoing prophylactic surgery has focused attention on the fallopian tube epithelium as the cell of origin and has led to the reporting of putative serous cancer precursor lesions. We therefore, sought to determine the expression of LKB1 in different histological subtypes of ovarian cancer and in early lesions; and the effect of loss of LKB1 on fallopian tube epithelial cells in vitro. Methodology: Archived sections of ovarian tumors were reviewed, paraffin blocks selected, and tissue microarrays created using triplicate 0.6 mm cores. The major histological types included were: high grade serous (n=201), non-serous (n=87), and low grade (micropapillary) (n=12) carcinomas, serous tumors of low malignant potential (n=26) and STICS (n=15). Immunohistochemistry for LKB1 protein (Santa Cruz mouse mAb sc-32245) was performed using standard techniques. Percentage of tumor cells with positive cytoplasmic staining (0–3), staining intensity (0–3) and histoscores were determined by viewing digitalized images with Aperio ImageScope software. A combined score of > 4 was considered positive. Fishers exact test with 95% confidence intervals was used to determine the significance of results. Fallopian tube epithelial cells were established from freshly digested tissue and infected with shRNA targeting LKB1. In vitro assays to determine proliferation and malignant transformation were used. Results: Loss of cytoplasmic LKB1 protein expression is more frequently observed in sporadic and hereditary high-grade serous carcinomas compared to other histological types, including low-grade serous carcinoma and serous tumors of low malignant potential. LKB1 may be exclusively involved in the high-grade serous oncogenic pathway and not in the development of low-grade serous carcinoma. Loss of LKB1 in early lesions was observed in 15/15 cases and indicates a role for in sporadic HGSC tumorigenesis in corporation with previously identified oncogenes. The frequency of LKB1 loss in high-grade tumors (67–69%) is similar to frequency of p53 mutations previously observed (70%). Citation Information: Cancer Prev Res 2011;4(10 Suppl):A11.

Abstract 5031: Insulin-like growth factor-1 (IGF-1) is upregulated in low-grade serous ovarian carcinoma

Abstract Introduction: Low-grade (LG) serous ovarian carcinomas are clinically and genetically distinct from high-grade serous ovarian carcinomas (HG), and emerging evidence supports that LG form a molecular continuum with serous borderline ovarian tumors (SBOT). Despite an improved survival, LG ovarian cancer is relatively chemoresistant, and difficult to treat when it recurs. We sought to identify and validate the upregulation of IGF-1 in low-grade serous ovarian carcinomas. Methods: Gene expression profiling was performed with Affymetrix U133 to identify genes over-expressed in LG tumors compared to SBOT. Over-expression of IGF-1 in 18 LG tumors was validated by quantitative real-time polymerase chain reaction (qRT-PCR) and compared to IGF-1 expression in 9 serous borderline ovarian tumors (SBOT) and 15 HG tumors. Immunohistochemistry (IHC) of IGF-1 was performed on SBOT, LG, and HG samples and graded according to staining intensity. A low-grade cell line (HOC-7) was used to generate IGF-1 receptor (IGF-1R) knockdown stable cell lines with shRNA. Similarly, an IGF-1 plasmid was transfected into HOC-7 cells with resultant IGF-1 over-expression. Cells were then treated with IGF-1 at a concentration of 100 ng/mL for 15 and 60 minutes with controls. Phospho-Akt, total Akt, IGF-1R, and β-actin expression was confirmed by Western Blot analysis. Cell migration assays were performed with an HOC-7 control and shRNA IGF-1R knockdown cell lines. Finally, expression of IGF-1R was performed on LG paraffin sections and graded according to staining intensity on 43 patients. Clinical data including survival status, overall survival, stage, and debulking status was gathered and Kaplan-Meier curves were generated according to staining intensity. Results: In the Affymetrix analysis, several genes were significantly differentially expressed in LG tumors, one of which was IGF-1. Based on qRT-PCR results, expression of IGF-1 was significantly higher in LG tumors than SBOT (p<0.0005) and HG carcinomas (p=0.033). LG tumors also exhibited more robust IGF-1 IHC staining than SBOT or HG specimens. Phospho-Akt expression increased with increasing time of exposure to IGF-1 and in the IGF-1 over-expressing cell line compared to controls; whereas phospho-Akt expression was decreased in the IGF-1R knockdown cell lines. Decreased cellular migration was noted in the IGF-1R knockdown compared to the control. In the IHC analysis, 92% of the 43 LG slides stained positive for IGF-1R expression; however, correlation between staining intensity and patient survival was not significant. Conclusions: IGF-1 is overexpressed in low-grade serous epithelial ovarian tumors, and activates the phospho-Akt pathway through the IGF-IR. Particularly in LG ovarian tumors, which are less sensitive to chemotherapy and difficult to cure upon recurrence, further clinical investigation into the utility of IGF-targeted therapy is warranted. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5031. doi:10.1158/1538-7445.AM2011-5031

High-Grade and Low-Grade Pelvic Serous Neoplasms Demonstrate Differential p53 Immunoreactivity in Peritoneal Washings

Objective: Serous neoplasms of the female pelvis share a müllerian phenotype. Unlike low-grade serous neoplasms (LGSNs), high-grade serous carcinomas (HGSCs) commonly display p53 mutations. The current study correlates p53 immunoreactivity in peritoneal washings with the cytologic interpretation and histology of the corresponding serous neoplasm. Study Design: Peritoneal washings from consecutive cases of pelvic serous neoplasms were identified (n = 45, 31 HGSCs and 14 LGSNs), with a control population selected from benign resections. Immunoreactivity for p53 was scored as a percentage of positive epithelioid cells by blinded manual cell count. Results: Washings from LGSNs and HGSCs were cytomorphologically positive with similar frequency (57 vs. 77%, respectively, p = 0.15, Fisher’s exact test). Immunoreactivity for p53 was not predictive of morphologic positivity. The percentage of p53-positive cells was higher in HGSCs (47 ± 42%), compared to LGSNs (9 ± 9%) and negative controls (2 ± 2%, n = 10). The difference in p53 immunoreactivity was statistically significant (p < 0.00009, ANOVA). Conclusions: The proportion of p53 immunoreactive cells was higher in cases of HGSCs, reflecting the importance of p53 mutations in high-grade serous tumorigenesis. The presence of p53 staining is not diagnostic for neoplastic cells; however, peritoneal washings are potential specimens in the investigation of serous neoplasia.

Distinct DNA methylation profiles in ovarian serous neoplasms and their implications in ovarian carcinogenesis

The purpose of this study was to analyze DNA methylation profiles among different types of ovarian serous neoplasm, which is a task that has not been performed. The Illumina beads array (Illumina Inc, San Diego, CA) was used to profile DNA methylation in enriched tumor cells that had been isolated from 75 benign and malignant serous tumor tissues and 6 tumor-associated stromal cell cultures. We found significantly fewer hypermethylated genes in high-grade serous carcinomas than in low-grade serous carcinoma and borderline tumors, which in turn had fewer hypermethylated genes than serous cystadenoma. Unsupervised analysis identified that serous cystadenoma, serous borderline tumor, and low-grade serous carcinomas tightly clustered together and were clearly different from high-grade serous carcinomas. We also performed supervised analysis to identify differentially methylated genes that may contribute to group separation. The findings support the view that low-grade and high-grade serous carcinomas are distinctly different with low-grade, but not high-grade, serous carcinomas that are related to serous borderline tumor and cystadenoma.

PAX8 Reliably Distinguishes Ovarian Serous Tumors From Malignant Mesothelioma

Ovarian serous neoplasms can have morphologic overlap with malignant mesothelioma. The distinction is clinically important, yet most studies have failed to identify immunostains that reliably distinguish these 2 tumor types. Recently, transcription factor PAX8 was shown to be a sensitive and relatively specific marker for Müllerian tumors. In addition, some studies suggest that h-caldesmon is sensitive and specific for mesothelioma when compared with serous ovarian tumors. The goal of this study was to evaluate whether PAX8 and h-caldesmon expression can successfully distinguish mesothelioma from serous ovarian tumors. Immunohistochemistry was carried out using PAX8 and h-caldesmon antibodies on archival tissue from 254 ovarian serous tumors and 50 mesothelial tumors. Nuclear and cytoplasmic immunoreactivity were considered positive for PAX8 and h-caldesmon, respectively. PAX8 staining was present in 99% of high-grade serous ovarian carcinomas and all (100%) low-grade ovarian carcinomas and serous borderline tumors; however, only 74% of these cases (188/254) were diffusely positive in more than 50% of tumors cells, and intensity ranged from strong to weak. None of the pleural malignant mesotheliomas were reactive with PAX8. However, 2/23 (9%) peritoneal malignant mesotheliomas showed focal and/or weak staining for PAX8; the remaining cases were negative. Two well-differentiated papillary mesotheliomas and 1 multicystic mesothelioma each showed some staining for PAX8. h-caldesmon was negative in all serous neoplasms and all mesothelial neoplasms, except 1 pleural malignant mesothelioma which showed patchy immunoreactivity. Strong PAX8 staining is highly specific (P<0.00001) for ovarian serous tumors when compared with malignant mesotheliomas of the peritoneum and pleura. The presence of weak staining for PAX8 in the 3 "noninvasive" mesotheliomas questions the use for PAX8 in this differential diagnosis. On the basis of this study, h-caldesmon is not a useful marker for mesothelioma.

Newly diagnosed and relapsed epithelial ovarian carcinoma: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up

Newly diagnosed and relapsed epithelial ovarian carcinoma: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up

Driver mutations in TP53 are ubiquitous in high grade serous carcinoma of the ovary

Numerous studies have tested the association between TP53 mutations in ovarian cancer and prognosis but these have been consistently confounded by limitations in study design, methodology, and/or heterogeneity in the sample cohort. High-grade serous (HGS) carcinoma is the most clinically important histological subtype of ovarian cancer. As these tumours may arise from the ovary, Fallopian tube or peritoneum, they are collectively referred to as high-grade pelvic serous carcinoma (HGPSC). To identify the true prevalence of TP53 mutations in HGPSC, we sequenced exons 2–11 and intron–exon boundaries in tumour DNA from 145 patients. HGPSC cases were defined as having histological grade 2 or 3 and FIGO stage III or IV. Surprisingly, pathogenic TP53 mutations were identified in 96.7% (n = 119/123) of HGPSC cases. Molecular and pathological review of mutation-negative cases showed evidence of p53 dysfunction associated with copy number gain of MDM2 or MDM4, or indicated the exclusion of samples as being low-grade serous tumours or carcinoma of uncertain primary site. Overall, p53 dysfunction rate approached 100% of confirmed HGPSCs. No association between TP53 mutation and progression-free or overall survival was found. From this first comprehensive mapping of TP53 mutation rate in a homogeneous group of HGPSC patients, we conclude that mutant TP53 is a driver mutation in the pathogenesis of HGPSC cancers. Because TP53 mutation is almost invariably present in HGPSC, it is not of substantial prognostic or predictive significance. Copyright © 2010 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Epidemiologic correlates of ovarian cortical inclusion cysts (CICs) support a dual precursor pathway to pelvic epithelial cancer

ObjectiveMany ovarian carcinomas are presumed to arise within ovarian cortical inclusion cysts (CICs). This study examined the frequency of ovarian CICs in relation to epidemiologic risk factors in women with BRCA1 and BRCA2 (BRCA+) mutations. MethodsBRCA+ women who underwent risk-reducing bilateral salpingo-oophorectomy were studied (n = 74). Fifteen demographic variables (e.g., age at time of surgery, age at first birth, age at menopause, body mass index (BMI), gravidity) from a review of the medical records and three pathologic variables (cystic and atretic follicles, corpora lutea) were recorded. Statistical associations were made using T-test or Chi Square analysis and logistic regression analysis for p-trend. ResultsWomen whose ovaries contained 7 for more CICs were older at first birth (p = 0.034), surgery (p = 0.059), menopause (p = 0.046) and had a higher BMI (p = 0.034) than those with <7 CICs. Regression analysis revealed a significant association between CICs and increasing BMI (p = 0.01). ConclusionsCICs correlate with greater body mass index, similar to low-grade serous and endometrioid tumors and in contrast to high-grade serous carcinoma and its putative precursor in the fallopian tube. A model is presented for ovarian and tubal pathways to pelvic cancer that are linked to different microscopic precursors with distinct epidemiologic correlates.

A petefészek serosus „borderline” tumorainak diagnosztikai nehézségei

About 15-20% of all ovarian neoplasms are of borderline type (or atypical proliferative or carcinoma of low malignant potential). They represent a common diagnostic and treatment problem both for the pathologist and for clinicians. The borderline tumors occur most commonly in childbearing age, show an indolent course and have good prognosis but are resistant to the traditional chemotherapies. The serous borderline tumors are the most common types of borderline ovarian tumors and they can cause differential diagnostic problems even for the experienced pathologist. We studied 30 cases which were diagnosed in our institute from 2000 to 2008. Thirteen were typical serous borderline tumors, in 7 cases the pattern was micropapillary, in 2 cases with microinvasion and in the remaining 8 cases the borderline tumors were associated with low-grade serous carcinomas. Seventeen of the 22 borderline cases were stage I tumors. There were noninvasive implants in the remaining 5 cases and in the cases of the low-grade carcinomas we could find, besides the noninvasive implants (in 3 cases), invasive implants or metastasis too. The main diagnostic problems in serous ovarian borderline tumors are the presence of micropapillary pattern, to detect microinvasion, or to differentiate the pseudo-borderline pattern of the low-grade serous tumors from a real borderline tumor and especially to diagnose the extraovarian diseases (types of implants). We discuss these diagnostic problems and criteria according to recent literature and our experience.

A Case of Ovarian Psammocarcinoma Associated with Endometrioid Cysts: A Morphological and Immunohistochemical Study

Psammocarcinoma of the ovary is an uncommon neoplasm, currently classified among the low-grade epithelial serous tumors. Little is known about its pathogenesis and biological behavior. A 35-year-old woman underwent laparotomic myomectomy and surgical removal of the right gonad after the incidental discovery of an adnexal mass. The pathological findings were consistent with serous psammocarcinoma and multiple endometrioid cysts of the ovary. Tissue specimens from the neoplasm were tested by immunohistochemistry for the p53, HER-2/neu and bcl-2 cancer-related proteins; diffuse overexpression for bcl-2 was detected, while tumor cells were negative for p53 and HER-2/neu. Although the pathogenesis and clinical course of ovarian psammocarcinoma are still to be determined, the molecular profile of this case highlights the similarities with ovarian tumors of the serous borderline group.

Low-grade serous ovarian cancer: a unique disease

Low-grade serous carcinomas represent approximately 10% of all serous ovarian carcinomas. A growing body of research has demonstrated several important differences between the clinical and molecular characteristics of these tumors and those of high-grade serous ovarian carcinomas. Patients with low-grade serous ovarian tumors are diagnosed at a younger age, have a longer overall survival, and have lower response rates to conventional chemotherapy. In addition, low-grade serous ovarian carcinomas have pathologic and molecular characteristics distinct from high-grade serous carcinomas, yet similar to serous tumors of low malignant potential. This suggests a common pathogenesis and a continuum of disease from serous tumors of low malignant potential to low-grade serous carcinomas. Further study, focusing specifically on low-grade serous carcinomas, is needed to determine the role of other chemotherapeutic agents, hormonal therapy, or targeted biologic agents in the treatment of this disease.

Assessment of TP53 mutation using purified tissue samples of ovarian serous carcinomas reveals a higher mutation rate than previously reported and does not correlate with drug resistance

The TP53 mutation frequency in ovarian serous carcinomas has been reported to range between 50% and 80%, but a stringent analysis of TP53 using purified epithelial samples has not yet been performed to accurately assess the mutation frequency and to correlate it with the histologic grade. The purpose of this study was to assess the TP53 mutational profile in a relatively large series of high-grade (53 primary and 18 recurrent) and 13 low-grade ovarian serous tumors using DNA isolated from affinity-purified tumor cells and to correlate it with in vitro drug resistance. All samples were affinity purified, and the tumor DNA was analyzed for TP53 mutations in exons 4-9. In vitro drug resistance assays to carboplatin, cisplatin, paclitaxel, and taxotere were performed on the same tumor samples and correlated with the TP53 mutation status. TP53 mutations were detected in 57 (80.3%) of 71 high-grade carcinomas and in one (7.8%) of 13 low-grade serous tumors (an invasive low-grade serous carcinoma). The mutations were predominantly missense mutations (59.6%). TP53 mutations were associated with high-grade serous carcinomas and recurrent disease (P < 0.0001). There was no statistically significant correlation between TP53 mutation status and drug resistance assays or clinical stage (P > 0.25). The frequency of TP53 mutations using purified tumor DNA from ovarian serous carcinomas was 80.3%, which is much higher than previously reported. Furthermore, we found that TP53 is not directly involved in the development of drug resistance in high-grade ovarian serous carcinomas.

Anti-tumor activity of letrozole in patients with recurrent advanced low malignant potential or low-grade serous ovarian tumors

5582 Purpose: To evaluate the clinical activity of oral Letrozole in patients with recurrent and advanced low malignant potential or low grade serous ovarian tumors and to determine the impact of steroid receptor expression on this observed activity. Methods: In a phase II design, we recruited patients with confirmed recurrent advanced stage low malignant potential tumors and recurrent low-grade serous carcinomas. Measurable disease was required. Steroid hormone expression (ER and PR), EGFR, and Her2/neu expression were determined on available pathological material by IHC from the initial surgery or at documentation of recurrent disease and blood was obtained before enrollment and every other month while on therapy. Letrozole was administered orally at a dose of 2.5 mg once a day. The endpoints were objective response rate assessed by Response Evaluation Criteria in Solid Tumor. Adverse events were graded using the National Cancer Institute Common Toxicity Criteria. Results: Thirteen patients meeting eligibility have been enrolled are evaluable for response and toxicity. From objective clinical parameters (RECIST) no patients had a CR or PR; five patients (38%) had disease stabilizations, eight patients had progressive disease. However, using criteria for CA 125 response, we obtained a complete serologic response in 2 of 13 patients (15%), and a partial serologic response in 2 additional patients (15%); marker stabilization was seen in 5 other patients (38%). CA125 increased in four patients (31%). We also detected the presence of ER, PR, EGFR, Her-2/Neu by IHC, and estradiol in the plasma by ELISA. No significant correlation was observed between tumor marker response and ER expression alone. However, when we evaluated the co-expression of ER/PR we found 3 of 5 (60%) patients had a serologic response compared to just 1 of 8 patients with ER+/PR- tumors (P=0.07). We observed no severe adverse events. Conclusion: Our preliminary data suggests that oral Letrozole has some antitumor activity in recurrent advanced low grade or borderline ovarian tumors and is well tolerated. The analysis of correlation between objective response and combined prediction markers including phosphorylated ER, PR, AKT, and IGFR is ongoing (Supported by CTRF). No significant financial relationships to disclose.

Amplicon profiles in ovarian serous carcinomas

Ovarian serous carcinoma is the most common and lethal type of ovarian cancer and its molecular etiology remains poorly understood. As an ongoing effort to elucidate the pathogenesis of ovarian serous carcinomas, we assessed the DNA copy number changes in 33 high-grade serous carcinomas and 10 low-grade serous tumors by using a genome-wide technique, single nucleotide polymorphism array, performed on affinity-purified tumor cells from fresh surgical specimens. Compared to low-grade tumors, high-grade serous carcinomas showed widespread DNA copy number changes. The most frequent alterations were in loci harboring candidate oncogenes: cyclin E1 (CCNE1), AKT2, Notch3 and PIK3CA as well as in novel loci, including 12p13, 8q24, 12p13 and 12q15. Seven amplicons were selected for dual color fluorescence in situ hybridization analysis in approximately 90 high-grade serous carcinomas and 26 low-grade serous tumors, and a high level of DNA copy number gain (amplification) was found in CCNE1, Notch3, HBXAP/Rsf-1, AKT2, PIK3CA and chr12p13 occurring in 36.1%, 7.8%, 15.7%, 13.6%, 10.8% and 7.3% of high-grade serous carcinomas. In contrast, we did not observe high level of ERBB2 amplification in any of the samples. Low-grade tumors did not show DNA copy number gain in any of the loci, except in 2 (8%) of 24 low-grade tumors showing low copy number gain in the Notch3 locus. Taken together, our results provide the first comprehensive analysis of DNA copy number changes in highly pure ovarian serous carcinoma. These findings may have important biological and clinical implications.

Expression of Extracellular Matrix Proteins in Ovarian Serous Tumors

The aims of this study were to perform a comprehensive expression analysis of the genes encoding extracellular matrix proteins and to investigate the expression pattern in one of these proteins, syndecan 1, in normal ovarian epithelium as well as benign and malignant ovarian serous tumors. Gene expression of 16 different extracellular matrix proteins was analyzed in ovarian serous tumors based on serial analysis of gene expression database. Semiquantitative reverse transcription-polymerase chain reaction was used to validate the serial analysis of gene expression result from each gene. As compared with normal ovarian surface epithelium, we found overexpression of syndecan 1, collagen type IV alpha 2, elastin microfibril interfase located protein 1, and laminin 5 in ovarian serous carcinomas. Syndecan 1 was selected for further study as it has not been well characterized in ovarian cancer and the syndecan 1 antibody was available for immunohistochemistry. Using a syndecan 1-specific monoclonal antibody, we demonstrated that syndecan 1 was expressed in 30.4% of high-grade serous carcinomas, 29.7% of low-grade carcinomas and serous borderline tumors, but none of benign serous cystadenomas and ovarian surface epithelium. Although both high-grade and low-grade serous carcinomas had a similar percentage of syndecan 1-positive cases, the immunointensity in high-grade carcinoma was significantly higher than that in low-grade carcinomas and serous borderline tumors (P = 0.007). In summary, ovarian carcinomas exhibit up-regulated expression of several extracellular matrix proteins, and syndecan 1 represents a novel tumor-associated marker in ovarian serous carcinomas.

Diffuse Mesothelin Expression Correlates with Prolonged Patient Survival in Ovarian Serous Carcinoma

Mesothelin is an emerging marker for cancer diagnosis and target-based therapy, yet relatively little is known about the clinical significance of mesothelin expression in tumors. In this study, we correlate mesothelin immunoreactivity to clinicopathologic features in ovarian serous carcinoma. Mesothelin expression levels were compared among 81 publicly available serial analysis of gene expression (SAGE) libraries of various carcinoma and normal tissue types. Immunohistochemistry using a well-characterized mesothelin monoclonal antibody (5B2) was done to evaluate mesothelin expression in 167 high-grade and 31 low-grade ovarian serous carcinomas. Immunohistochemistry staining scores were correlated with patient survival, tumor site, tumor grade, in vitro drug resistance, and differentiation status of tumor cells. SAGE analysis showed that mesothelin was overexpressed in 50% of ovarian and pancreatic carcinomas but rarely in other cancer types, including liver, colon, kidney, prostate, and breast. Mesothelin immunoreactivity (>5% of tumor cells) was present in 55% of ovarian serous carcinomas with no difference in expression between high-grade and low-grade serous tumors (P = 0.82). Based on Kaplan-Meier analysis, we found that a diffuse mesothelin staining (>50% of tumor cells) in primary high-grade ovarian carcinomas correlated significantly with prolonged survival in patients who had advanced-stage disease and had received optimal debulking surgery followed by chemotherapy (P = 0.023). Mesothelin expression did not correlate significantly with patient age, tumor site, in vitro drug resistance, or tumor differentiation status (P > 0.10). Our results provided new evidence that mesothelin expression is associated with prolonged survival in patients with high-grade ovarian serous carcinoma.