Serous carcinogenesis in the fallopian tube: a descriptive classification

The immunomodulating roles of glycoproteins in epithelial ovarian cancer

The complexity of the immune system demands an intricate defense mechanism by tumors. Ovarian and other tumors employ specific glycoproteins and the associated glycan sequences to modulate immune responses. Glycoproteins enable tumor cells that express or secrete these molecules to evade immune cell attack and induce the immune system to promote tumor growth. This review focuses first on the immune environment in ovarian cancer, and the mechanisms of activation and inhibition that immune cells undergo in order to either attack or ignore a target cell. Next we illustrate the immunomodulatory roles of ovarian cancer-associated glycans and glycoproteins in 1. preventing immune synapse formation, 2. serving as ligands of immune cell receptors, 3. scavenging cytokines and chemokines, and 4. participating in the formation of autoantibodies against the tumor. The importance of these immunomodulating strategies from the view points of understanding the tumor immunology of ovarian tumors, potential origin of such mechanisms, and specific strategies to circumvent the glycoconjugate-mediated suppression of immune responses is discussed in this review.

p53 signature and serous tubal in-situ carcinoma in cases of primary tubal and peritoneal carcinomas and serous borderline tumors of the ovary

The objective of this study was to evaluate the role of the fimbriated end and nonfimbriated epithelium of fallopian tubes with regard to p53 signature, tubal intraepithelial lesions in transition (TILT), and serous tubal in-situ carcinoma (STIC) in cases of different kinds of serous pelvic cancer. This study immunohistochemically evaluated (by Ki-67 and p53 staining) the presence of p53 signature, TILT lesions, and STIC in 14 consecutive cases of prophylactic salpingo-oophorectomy in women with BRCA-1/2 mutation (bilateral salpingo-oophorectomy), 11 cases of macroscopically inconspicuous adnexae of patients with primary contralateral tubal cancer (TC), 9 cases of primary peritoneal cancer (PPC), and 10 cases of serous ovarian borderline tumors, evaluating the fallopian tubes (using the Sectioning and Extensively Examining the FIMbria protocol), ovarian surface epithelium, and ovarian cortical inclusion cysts. The frequencies of p53 signature, TILT, and STIC were 35.7%, 7.1%, and 0% in cases of prophylactic surgery, 18.2%, 9.1%, and 18.2% in TC, and 11.1%, 0%, and 33.3% in PPC. These precursor lesions were missed during the initial routine screening and were found in the fimbriated end of the fallopian tubes in 94%. In 1 case of PPC, staining for p53 was negative in STIC. The studied adnexal tissue of serous ovarian borderline tumor and ovarian cortical inclusion cysts of all cases showed no alterations according to p53 signature, TILT, or STIC. STIC and p53 signature as precursor lesions of pelvic serous cancer were seen in macroscopically inconspicuous contralateral fallopian tubes in unilateral TC, in patients with elective bilateral salpingo-oophorectomy, and in patients affected by PPC. Therefore, we propose the complete processing of adnexal tissue and the use of step sectioning to establish the correct diagnosis. Immunohistochemistry for p53 and ki-67 may aid in the diagnosis, but is not necessary for routine investigation.

Evaluating the progenitor cells of ovarian cancer: analysis of current animal models

Serous ovarian cancer is one of the most lethal gynecological malignancies. Progress on effective diagnostics and therapeutics for this disease are hampered by ambiguity as to the cellular origins of this histotype of ovarian cancer, as well as limited suitable animal models to analyze early stages of disease. In this report, we will review current animal models with respect to the two proposed progenitor cells for serous ovarian cancer, the ovarian surface epithelium and the fallopian tube epithelium.

Toward an integrative analysis of the tumor microenvironment in ovarian epithelial carcinoma

Ovarian epithelial carcinomas are heterogeneous malignancies exhibiting great diversity in histological phenotypes as well as genetic and epigenetic aberrations. A general early event in tumorigenesis is regional dissemination into the peritoneal cavity. Initial spread to the peritoneum is made possible by cooperative signaling between a wide array of molecules constituting the tissue microenvironment in the coelomic epithelium. Changes in the activity of key microenvironmental components not constitutively expressed in normal tissue, including several disclosed adhesion molecules, growth factors, proteases, and G-protein coupled receptors (GPCRs), coordinate the transition. Remodeling of the extracellular matrix (ECM) and subsequent cell surface interactions enable transformation by promoting chromosomal instability (CIN) and stimulating several common signal transduction cascades to prepare the tissue for harboring and facilitating growth, angiogenesis and metastasis of the developing tumor.

Ovarian cancer risk factors by histologic subtypes in the NIH-AARP Diet and Health Study

Data suggest that risk factors for ovarian carcinoma vary by histologic type, but findings are inconsistent. We prospectively evaluated risk factors by histological subtypes of incident ovarian cancer (n = 849) in a cohort of 169,391 women in the NIH-AARP Diet and Health Study. We constructed Cox models of individual exposures by comparing case subtypes to the entire non-case group and assessed p-heterogeneity in case-case comparisons using serous as the reference category. Substantial risk differences between histologic subtypes were observed for menopausal hormone therapy (MHT) use, oral contraceptive (OC) use, parity and body mass index (p-heterogeneity = 0.01, 0.03, 0.05, 0.03, respectively). MHT users were at increased risk for all histologic subtypes except for mucinous carcinomas, where risk was reduced (relative risk (RR) = 0.37; 95% confidence interval (CI): 0.18, 0.80). OC users were only at significantly decreased risk for serous cancers (RR = 0.69; 95% CI: 0.55, 0.85). Although parity was inversely associated with risk of all subtypes, the RRs ranged from 0.28 (clear cell) to 0.83 (serous). Obesity was a significant risk factor only for endometrioid cancers (RR = 1.64; 95% CI: 1.00, 2.70). Our findings support a link between etiological factors and histological heterogeneity in ovarian carcinoma.

Stathmin 1, a marker of PI3K pathway activation and regulator of microtubule dynamics, is expressed in early pelvic serous carcinomas

BACKGROUND

Most high-grade pelvic serous carcinomas (HGPSCs) arise from fallopian tube epithelium (FTE). To date, few markers have been shown to characterize FTE transformation. Stathmin 1 (STMN1) is a candidate oncogene whose activity is influenced by p53, p27Kip1 (p27), and PI3K/Akt pathway activation. As a microtubule destabilizing protein, STMN1 regulates cytoskeletal dynamics, cell cycle progression, mitosis, and cell migration. This study examines the expression of STMN1 and its negative regulator p27 along the morphologic continuum from normal FTE to invasive carcinoma.

METHODS

STMN1 and p27 expression were examined by immunohistochemistry (IHC) in benign (n=12) and malignant (n=13) fallopian tubes containing normal epithelium, morphologically benign putative precursor lesions ("p53 signatures"), potential transitional precursor lesions ("proliferative p53 signatures"), tubal intraepithelial carcinoma (TIC), and/or invasive serous carcinoma. STMN1 expression was further assessed in 131 late-stage HGPSCs diagnosed as primary ovarian and in 6 ovarian cancer cell lines by IHC and Western blot, respectively.

RESULTS

STMN1 expression was absent in benign FTE and infrequently detected in p53 signatures. However, it was weakly expressed in proliferative p53 signatures and robustly induced upon progression to TIC and invasive carcinoma, typically accompanied by decreased p27 levels. STMN1 was expressed in >80% of high-grade serous ovarian carcinomas and cell lines.

CONCLUSIONS

STMN1 is a novel marker of early serous carcinoma that may play a role in FTE tumor initiation. Our data are consistent with a model by which STMN1 overexpression, resulting from loss of p27-mediated regulation, may potentiate aberrant cell proliferation, migration, and/or loss of polarity during early tumorigenesis.

The impact of ovulation on fallopian tube epithelial cells: evaluating three hypotheses connecting ovulation and serous ovarian cancer

Ovarian cancer is the most lethal gynecological malignancy affecting American women. Current hypotheses concerning the etiology of ovarian cancer propose that a reduction in the lifetime number of ovulations decreases ovarian cancer risk. Advanced serous carcinoma shares several biomarkers with fallopian tube epithelial cells, suggesting that some forms of ovarian carcinoma may originate in the fallopian tube. Currently, the impact of ovulation on the tubal epithelium is unknown. In CD1 mice, ovulation did not increase tubal epithelial cell (TEC) proliferation as measured by bromodeoxyuridine incorporation and proliferating cell nuclear antigen staining as compared to unstimulated animals. In superovulated mice, an increase in the number of pro-inflammatory macrophages was detected in the oviduct. Ovulation also increased levels of phospho-γH2A.X in TEC, indicating that these cells were susceptible to double-strand DNA breakage following ovulation. To determine which components of ovulation contributed to DNA damage in the fallopian tube, an immortalized baboon TEC cell line and a three-dimensional organ culture system for mouse oviduct and baboon fallopian tubes were developed. TEC did not proliferate or display increased DNA damage in response to the gonadotropins or estradiol alone in vitro. Oxidative stress generated by treatment with hydrogen peroxide or macrophage-conditioned medium increased DNA damage in TEC in culture. Ovulation may impact the fallopian tube epithelium by generating DNA damage and stimulating macrophage infiltration but does not increase proliferation through gonadotropin signaling.

Molecular pathogenesis and extraovarian origin of epithelial ovarian cancer--shifting the paradigm

Recent morphologic, immunohistochemical, and molecular genetic studies have led to the development of a new paradigm for the pathogenesis and origin of epithelial ovarian cancer based on a dualistic model of carcinogenesis that divides epithelial ovarian cancer into 2 broad categories designated types I and II. Type I tumors comprise low-grade serous, low-grade endometrioid, clear cell and mucinous carcinomas, and Brenner tumors. They are generally indolent, present in stage I (tumor confined to the ovary), and are characterized by specific mutations, including KRAS, BRAF, ERBB2, CTNNB1, PTEN, PIK3CA, ARID1A, and PPP2R1A, which target specific cell signaling pathways. Type I tumors rarely harbor TP53 mutations and are relatively stable genetically. Type II tumors comprise high-grade serous, high-grade endometrioid, malignant mixed mesodermal tumors (carcinosarcomas), and undifferentiated carcinomas. They are aggressive, present in advanced stage, and have a very high frequency of TP53 mutations but rarely harbor the mutations detected in type I tumors. In addition, type II tumors have molecular alterations that perturb expression of BRCA either by mutation of the gene or by promoter methylation. A hallmark of these tumors is that they are genetically highly unstable. Recent studies strongly suggest that fallopian tube epithelium (benign or malignant) that implants on the ovary is the source of low-grade and high-grade serous carcinoma rather than the ovarian surface epithelium as previously believed. Similarly, it is widely accepted that endometriosis is the precursor of endometrioid and clear cell carcinomas and, as endometriosis, is thought to develop from retrograde menstruation; these tumors can also be regarded as involving the ovary secondarily. The origin of mucinous and transitional cell (Brenner) tumors is still not well established, although recent data suggest a possible origin from transitional epithelial nests located in paraovarian locations at the tuboperitoneal junction. Thus, it now appears that type I and type II ovarian tumors develop independently along different molecular pathways and that both types develop outside the ovary and involve it secondarily. If this concept is confirmed, it leads to the conclusion that the only true primary ovarian neoplasms are gonadal stromal and germ cell tumors analogous to testicular tumors. This new paradigm of ovarian carcinogenesis has important clinical implications. By shifting the early events of ovarian carcinogenesis to the fallopian tube and endometrium instead of the ovary, prevention approaches, for example, salpingectomy with ovarian conservation, may play an important role in reducing the burden of ovarian cancer while preserving hormonal function and fertility.

Phenotypic heterogeneity and instability of human ovarian tumor-initiating cells

The cancer stem cell (CSC) model proposes that tumors have a hierarchical organization in which only some cells indefinitely self-renew and thereby sustain tumor growth. In addition, the CSC model requires that tumor-initiating cells (TICs) be prospectively isolatable on the basis of their phenotype. Previous studies have suggested that serous ovarian cancer (SOC) conforms to the CSC model, but these used arguably nonfidelitous immortalized cell lines, cultured primary cells, or passaged xenografts as the source of tumor cells. We developed a robust assay for quantifying TICs from primary SOC. Using this assay, we find that TICs are rare when assayed in either NOD/SCID or NOD/SCID/IL2Rγ(-/-) (NSG) mice. TIC frequency (TICf) varies substantially between patients, although it is similar in primary ovarian masses and omental metastases, suggesting that TICf is an intrinsic property of ovarian tumors. CD133 marks all TICs from several primary SOC cases. However, in other cases, substantial TIC activity is found in both the CD133(+) and CD133(-) fractions, whereas still other cases have exclusively CD133(-) TICs. Furthermore, the TIC phenotype can change in xenografts: primary tumors in which all TICs are CD133(+) can give rise to xenografts that contain substantial numbers of CD133(-) TICs. Our results highlight the need for quantitative rigor in the evaluation of TICs and for caution when using passaged xenografts for such studies. Furthermore, although our data suggest that SOC conforms to the CSC hypothesis, the heterogeneity of the TIC phenotype may complicate its clinical application.

Molecular Pathology of Ovarian Carcinomas

This content presents a review of molecular pathology of ovarian cancer. The authors present key molecular features for high-grade and low-grade serous carcinomas, endometrioid carcinomas, clear cell carcinomas, and mucinous carcinomas. Cell lineage, mutation and gene expression, pathway alterations, risk factors, prognostic markers, and treatment targets are discussed.

The impact of tissue block sampling on the detection of p53 signatures in fallopian tubes from women with BRCA 1 or 2 mutations (BRCA+) and controls

The tubal p53 signature is a putative precursor to pelvic serous carcinoma, but its frequencies in women with inherited mutations in the BRCA1 or BRCA2 genes (BRCA+) and controls has been controversial. An initial section and two levels (100-200 μm) from every block in BRCA+ (24) and control tubes (40) were stained for p53. The frequency of p53 signatures was computed between the populations and across the three levels from each block, and analyzed by Fisher exact test. A total of 17 (71%) BRCA+ and 20 (50%) control tubes were p53 signature positive (P=0.12); 21 and 16% of all tissue blocks sectioned harbored signatures (P=0.29), and 76 and 67% were found in the fimbria. In 49 and 32% of p53 signature positive cases in the two groups, the p53 signatures were not discovered until the second or third round of sectioning. In all, 38 and 40% of BRCA+ and control subjects harbored p53 signatures in more than one focus in a single block. In one case (BRCA+), a highly atypical proliferation was identified in one serial section. The p53 signatures are more common than previously reported and the frequency of detection increases as a function of sectioning through the tissue block, both in absolute frequency and in numbers of p53 signatures detected in a given block. There is a trend for a higher absolute frequency of p53 signatures (71 vs 50%; P=0.12) in BRCA+ subjects, but this is not reflected in a greater average number of p53 signatures or positive blocks per case. This study underscores the importance of systematic immunohistochemical examination of fallopian tubes when conducting epidemiological studies that compare the frequency of p53 signatures in different populations. Attention to this detail is critical when exploring risk factors germane to early serous carcinogenesis.

Carcinomas of Distal Fallopian Tube and Their Association with Tubal Intraepithelial Carcinoma: Do They Share a Common "Precursor" Lesion? Loss of Heterozygosity and Immunohistochemical Analysis Using PAX 2, WT-1, and P53 Markers

As the role of distal fallopian tube as organ of serous carcinogenesis is emerging, additional literature on the role of tubal intraepithelial carcinoma (TIC) as a precursor lesion in a subset of primary peritoneal serous carcinomas (PPSC is emerging as well. TIC although fallopian tube in origin can be genetically related to ovarian/peritoneal carcinomas. The role of PAX2 in primary fallopian tube carcinomas (PFTC)/PPSC is yet to be defined. The aim of our study was to understand if the biologic properties of tumors arising in the distal fallopian tube that remain as PFTC are different when they seed on to the peritoneal surface (PPSC). A panel of 6 polymorphic microsatellite markers corresponding to p53, PAX2, and WT1 tumor suppressor genes were studied. Invasive carcinomas as well as TIC arising in the distal fallopian tube when remain as PFTC appears to exhibit different LOH patterns in comparison to PPSC. PAX 2 LOH patterns might represent a “hidden PAX 2 signature” analogous to p53 signatures. PAX 2 might be an emerging marker for detection of early serous carcinomas particularly in BRCA + women.

Are all pelvic (nonuterine) serous carcinomas of tubal origin?

It has been proposed that the presence of tubal intraepithelial carcinoma (TIC), in association with one-third to nearly half of pelvic serous carcinomas, is evidence of fallopian tube origin for high-grade serous carcinomas that would have been otherwise classified as primary ovarian or peritoneal. To address this hypothesis, we evaluated a series of 114 consecutive pelvic (nonuterine) gynecologic carcinomas at our institution (2006 to 2008) to determine the frequency of TIC in 52 cases in which all the resected fallopian tube tissue was examined microscopically. These 52 cases were classified as ovarian (n=37), peritoneal (n=8), or fallopian tube (n=7) in origin as per conventional criteria based on disease distribution. The presence of TIC and its location and relationship to invasive carcinoma in the fallopian tubes and ovaries were assessed. Among the 45 cases of ovarian/peritoneal origin, carcinoma subtypes included 41 high-grade serous, 1 endometrioid, 1 mucinous, 1 high-grade, not otherwise specified, and 1 malignant mesodermal mixed tumor. TIC was identified in 24 cases (59%) of high-grade serous carcinoma but not among any of the other subtypes; therefore, the term serous TIC (STIC) is a more specific appellation. STICs were located in the fimbriated end of the tube in 22 cases (92%) and in the ampulla in 2 (8%); they were unilateral in 21 (88%) and bilateral in 3 (13%). STICs in the absence of an associated invasive carcinoma in the same tube were detected in 7 cases (30%) and with invasive carcinoma in the same tube in 17 (71%). Unilateral STICs were associated with bilateral ovarian involvement in 15 cases and unilateral (ipsilateral) ovarian involvement in 5 (the remaining case with a unilateral STIC had a primary peritoneal tumor with no ovarian involvement); the bilateral STICs were all associated with bilateral ovarian involvement. Six of the 7 primary tubal tumors were high-grade serous carcinomas, and 4 of these 6 (67%) had STICs. Based on conventional criteria, 70%, 17%, and 13% of high-grade serous carcinomas qualified for classification as ovarian, peritoneal, and tubal in origin, respectively; however, using STIC as a supplemental criterion to define a case as tubal in origin, the distribution was modified to 28%, 8%, and 64%, respectively. Features of tumors in the ovary that generally suggest metastatic disease (bilaterality, small size, nodular growth pattern, and surface plaques) were identified with similar frequency in cases with and without STIC and were, therefore, not predictive of tubal origin. The findings, showing that nearly 60% of high-grade pelvic (nonuterine) serous carcinomas are associated with STICs, are consistent with the proposal that the fallopian tube is the source of a majority of these tumors. If these findings can be validated by molecular studies that definitively establish that STIC is the earliest form of carcinoma rather than intraepithelial spread from adjacent invasive serous carcinoma of ovarian or peritoneal origin, they will have important clinical implications for screening, treatment, and prevention.

Serous tubal intraepithelial carcinoma: diagnostic reproducibility and its implications

Serous tubal intraepithelial carcinoma (STIC) is detected in between 5% and 7% of women undergoing risk-reduction salpingooophorectomy for mutations in the BRCA1 or 2 genes (BRCA+), and seems to play a role in the pathogenesis of many ovarian and "primary peritoneal" serous carcinomas. The recognition of STIC is germane to the management of BRCA+ women; however, the diagnostic reproducibility of STIC is unknown. Twenty-one cases were selected and classified as STIC or benign, using both hematoxylin and eosin and immunohistochemical stains for p53 and MIB-1. Digital images of 30 hematoxylin and eosin-stained STICs (n=14) or benign tubal epithelium (n=16) were photographed and randomized for blind digital review in a Powerpoint format by 6 experienced gynecologic pathologists and 6 pathology trainees. A generalized kappa statistic for multiple raters was calculated for all groups. For all reviewers, the kappa was 0.333, indicating poor reproducibility; kappa was 0.453 for the experienced gynecologic pathologists (fair-to-good reproducibility), and kappa=0.253 for the pathology residents (poor reproducibility). In the experienced group, 3 of 14 STICs were diagnosed by all 6 reviewers, and 9 of 14 by a majority of the reviewers. These results show that interobserver concordance in the recognition of STIC in high-quality digital images is at best fair-to-good for even experienced gynecologic pathologists, and a proportion cannot be consistently identified even among experienced observers. In view of these findings, a diagnosis of STIC should be corroborated by a second pathologist, if feasible.

Drug development for cancer chemoprevention: focus on molecular targets

With biomolecular evidence accumulating at an exponential rate, there will be a surge in the development of targeted cancer prevention drugs and interventions in the next decade. Promising results from clinical treatment trials identify a spectrum of targeted cancer therapies in several broad categories. These include both small molecule inhibitors of either key receptors or enzyme binding sites, as well as intravenously delivered monoclonal antibodies that block a specific binding interaction between ligands and their receptors. These targeted interventions conform to a basic translational algorithm: biomarker present, biomarker modulated, and biomarker clinically relevant. A review of solid tumor targets provides a manageable list of factors that are critical to cancer cell survival. As such, these targets represent factors that are not only clinically relevant but also may play a critical role in early tumor development prior to the evolution of frank invasive malignancy. This possibility qualifies these targets for consideration in the development of cancer prevention interventions. Among solid tumors, the treatment of breast cancer with targeted drugs has a long record benchmarked by the initial US Food and Drug Administation (FDA) approval of tamoxifen for metastatic breast cancer treatment in 1977. Since then, the list of oncology drug targets has expanded to include aromatase, androgen receptor, the epidermal growth factor receptor (EGFR) family, and others. It is not surprising that tamoxifen was the first of the modern targeted therapies to be approved for cancer risk reduction and additional approvals are anticipated. The focus of this review is the pharmacologic manipulation of targets within epithelial tumor cells and the implication of those targets for intervening to suppress and eliminate premalignant cells in human tissue. Major obstacles to prevention drug development can be addressed by attention to two important areas. One of these is the refinement of early phase prevention trials to identify drug targets in epithelial cells that are at demonstrated risk of evolving into cancer cells, ie, cells from a developmental niche in cancer ontogeny. Early results suggest that molecular risk signatures may allow the investigational identification of molecular targets in premalignant tissue, with the possibility that chemoprevention agents can be used to eliminate the risk signature. To the extent that this approach can be developed, it will allow for cancer risk reduction in a way that is analogous to the measurement of tumor response to treatment. Even with improvements in the efficiency of clinical trials that come from using molecular risk signatures, there is an ever-growing list of chemoprevention agents that are candidates for evaluation. Improved prevention drug screening methodologies are therefore needed to prioritize agents for clinical testing. In addition to drug targets located in epithelial tumor cells, another list of malignancy-associated targets could be generated by considering targets in tumor-associated stromal and endothelial cells (eg, fibroblast growth factor [FGF], vascular endothelial growth factor [VEGF]), as well as targets related to a systemic reservoir of circulating cells that can be recruited to carcinogenic influence by inflammatory factors such as nuclear factor (NF)kappaB. The complementarities of target-related processes within tumors cells, in the tumor microenvironment, and beyond suggests that there is great potential for multi-targeted approaches that may be more effective than single agents and also less prone to resistance. Additional options, related to drug dose and schedule, remain to be established. As long as multiple agents can be used in combination for optimal effect with acceptable toxicity, the co-targeting of the epithelial cell compartment along with other compartments of oncogenic activity is expected to expand the dimensions of targeted prevention and enhance the overall opportunity to eliminate precancer or cells at risk of eventually transitioning to invasive cancer.

Mucosal carcinoma of the fallopian tube coexists with ovarian cancer of serous subtype only: a study of Japanese cases

Previous studies in Western countries have revealed that mucosal carcinoma of the fallopian tube frequently coexists with pelvic (ovarian, tubal, and peritoneal) serous carcinomas, and early tubal carcinoma is now regarded as a possible origin of these tumors. However, the relationship between early tubal carcinoma and non-serous ovarian cancer, such as clear cell adenocarcinoma, has not been studied in detail. In this study, we sought to examine the coexistence of mucosal carcinoma of the fallopian tube in Japanese ovarian cancer cases. We submitted the fallopian tubes in toto for histological examination in 52 ovarian carcinoma cases and three peritoneal serous carcinoma cases. The ovarian tumors included 12 serous adenocarcinomas, 23 clear cell adenocarcinomas, nine endometrioid adenocarcinomas, three mucinous adenocarcinomas, and four mixed epithelial carcinomas. Mucosal carcinoma of the fallopian tube did not coexist with non-serous adenocarcinoma (n = 40). In contrast, mucosal carcinoma of the fallopian tube was observed in six cases of ovarian serous adenocarcinoma and one case of peritoneal serous adenocarcinoma. In these cases, the p53 immunophenotypes were similar in tubal lesions and invasive ovarian or peritoneal carcinomas. Tumors were negative for p53 in four of seven cases, and one of the p53-negative serous adenocarcinomas showed low-grade morphology. We believe that some ovarian and peritoneal serous adenocarcinomas develop from early tubal carcinomas. However, it should be noted that early tubal carcinomas are not always p53-positive immunohistochemically. Finally, it is unlikely that early tubal lesions are involved in the carcinogenesis of clear cell adenocarcinoma and other non-serous adenocarcinomas.

A pathologist's road map to benign, precancerous, and malignant intraepithelial proliferations in the fallopian tube

The fallopian tube has recently emerged as an important site of origin for not only early serous cancer in women with inherited mutations in BRCA1/BRCA2 but as a source of many pelvic serous carcinomas. With this increased attention has come the inevitable need to sort out what epithelial abnormalities are clinically important and how they should be reported by the practicing pathologist. This review addresses 4 categories of tubal epithelial change: (1) metaplasias; (2) nonmalignant atypias; (3) potential precursors, including secretory cell outgrowths and p53 signatures; and (4) tubal intraepithelial carcinomas. A modified protocol for sectioning the fallopian tube (SEE-FIM) is discussed and each of the above topics is covered in the context of its differential diagnosis and recommendations for reporting are included. Finally, the rationale for close inspection of the tube, both in presumed benign and malignant disease, is discussed, with reference to an ongoing multi-institutional web-based project (Pelvic-ovarian Cancer Interception project).

Secretory cell outgrowth, PAX2 and serous carcinogenesis in the Fallopian tube

The 'p53 signature' is a benign secretory cell outgrowth in the distal Fallopian tube that shares properties with ovarian serous cancer-including p53 mutations-and is a putative serous cancer precursor. We expanded the precursor definition to all secretory cell outgrowths (SCOUTs) of 30 or more cells and scored normal (N) and altered (A) expression of both p53 and PAX2, a gene down-regulated in ovarian and endometrial cancer. SCOUTs were identified by BCL2/p73 staining in tubes from women with serous carcinoma, inherited mutations in BRCA1 or BRCA2 and controls. SCOUTs were prevalent in both proximal and distal tube and significantly associated with serous carcinoma versus the others (p < 0.001); 89% were PAX2 (A) and 26% were PAX2 (A)/p53 (A) (p53 signatures). PAX2 (A)/p53 (N) SCOUTs were free of p53 mutations; however, 12 of 13 p53 signatures were PAX2 (A). A tubal carcinoma and contiguous SCOUT were p53 (A)/PAX2 (A) and shared the same p53 mutation. SCOUTs are discretely localized alterations commonly containing altered expression of multiple genes within histologically benign tubal epithelium. Geographic distribution in the tube varies by genotype and immunophenotype, from regionally unrestricted (PAX2) to greater likelihood specific area (fimbria) of shared prevalence (PAX2 and p53). This study reveals, for the first time, an entity (SCOUT) that is associated with serous cancer, expands the topography of altered PAX2 expression in the female genital tract mucosa and highlights another potential pathway disturbance involved in early serous carcinogenesis in the Fallopian tube.

An inconspicuous fallopian-tube carcinoma clinically manifested as a rectovaginal septal tumor: a pitfall for diagnosis and treatment

We report an unusual metastasis of an inconspicuous fallopian-tube carcinoma to the rectovaginal septum in a 67-year-old woman. The 4-cm tumor of serous adenocarcinoma was identified in the rectovaginal space with intact vaginal and rectal mucosa. The patient underwent an abdominoperineal resection with adjacent rectum and the bilateral uterine annexes, which were macroscopically intact. Unexpectedly, invasive and intraepithelial serous adenocarcinoma in fallopian-tube fimbria was microscopically observed, suggesting that the fallopian fimbria was the origin of the rectovaginal septum tumor. The clonality of these two tumors was confirmed by the presence of an identical single nucleotide point mutation in TP53. The patient received six cycles of adjuvant paclitaxel and carboplatin combination chemotherapy. There was no sign of recurrence after 17 months of treatment. This case study demonstrates that the fallopian-tube carcinoma, which exhibited minimal growth in the primary site, has the potential to metastasize to the retroperitoneal space and suggests that the fallopian-tube fimbria must be closely examined in cases of adenocarcinoma of unknown origin.

Precursor lesions of high-grade serous ovarian carcinoma: morphological and molecular characteristics

The lack of proven screening tools for early detection and the high mortality of ovarian serous carcinoma (OSC), particularly high grade, have focused attention on identifying putative precursor lesions with distinct morphological and molecular characteristics. The finding of occult invasive and intraepithelial fallopian tube carcinomas in prophylactically removed specimens from asymptomatic high-risk BRCA 1/2-mutation carriers supports the notion of an origin for OSC in the fallopian tube. The intraepithelial carcinomas have been referred to as serous intraepithelial carcinomas (STICs) but our own findings (unpublished data) and recent reports have drawn attention to a spectrum of changes that fall short of STICs that we have designated serous tubal intraepithelial lesions (STILs).

The origin and pathogenesis of epithelial ovarian cancer: a proposed unifying theory

Ovarian cancer is the most lethal gynecologic malignancy. Efforts at early detection and new therapeutic approaches to reduce mortality have been largely unsuccessful, because the origin and pathogenesis of epithelial ovarian cancer are poorly understood. Despite numerous studies that have carefully scrutinized the ovaries for precursor lesions, none have been found. This has led to the proposal that ovarian cancer develops de novo. Studies have shown that epithelial ovarian cancer is not a single disease but is composed of a diverse group of tumors that can be classified based on distinctive morphologic and molecular genetic features. One group of tumors, designated type I, is composed of low-grade serous, low-grade endometrioid, clear cell, mucinous and transitional (Brenner) carcinomas. These tumors generally behave in an indolent fashion, are confined to the ovary at presentation and, as a group, are relatively genetically stable. They lack mutations of TP53, but each histologic type exhibits a distinctive molecular genetic profile. Moreover, the carcinomas exhibit a shared lineage with the corresponding benign cystic neoplasm, often through an intermediate (borderline tumor) step, supporting the morphologic continuum of tumor progression. In contrast, another group of tumors, designated type II, is highly aggressive, evolves rapidly and almost always presents in advanced stage. Type II tumors include conventional high-grade serous carcinoma, undifferentiated carcinoma, and malignant mixed mesodermal tumors (carcinosarcoma). They displayTP53 mutations in over 80% of cases and rarely harbor the mutations that are found in the type I tumors. Recent studies have also provided cogent evidence that what have been traditionally thought to be primary ovarian tumors actually originate in other pelvic organs and involve the ovary secondarily. Thus, it has been proposed that serous tumors arise from the implantation of epithelium (benign or malignant) from the fallopian tube. Endometrioid and clear cell tumors have been associated with endometriosis that is regarded as the precursor of these tumors. As it is generally accepted that endometriosis develops from endometrial tissue by retrograde menstruation, it is reasonable to assume that the endometrium is the source of these ovarian neoplasms. Finally, preliminary data suggest that mucinous and transitional (Brenner) tumors arise from transitional-type epithelial nests at the tubal-mesothelial junction by a process of metaplasia. Appreciation of these new concepts will allow for a more rationale approach to screening, treatment, and prevention that potentially can have a significant impact on reducing the mortality of this devastating disease.

The Li-Fraumeni syndrome (LFS): a model for the initiation of p53 signatures in the distal Fallopian tube

A candidate early precursor to pelvic serous cancer, the 'p53 signature', is commonly found in the benign mucosa of the distal Fallopian tube and harbours p53 mutations and evidence of DNA damage. We examined tubes from women with pre-existing (germ-line) mutations in p53 [Li-Fraumeni syndrome (LFS)] for evidence of this precursor. Fallopian tubes from two cases of LFS were immunostained for p53, Ki-67 (proliferation) and H2AX (DNA damage response) and analysed for p53 mutations by laser capture microdissection (LCM) and p53 genomic sequencing (exons 2-11). A common single nucleotide repeat (snp) in exon 3 (rs1042522) and deletion sequencing chromatograms in exon 4 were examined in combination to estimate LOH in both LFS tubes and advanced serous carcinomas from the general population. LFS tubal epithelium contained abundant (10-20 per section) p53 signatures with evidence of DNA damage and low proliferative activity. Six of 11 LFS microdissected p53 signatures (55%) and 15 of 21 serous carcinomas (71%) revealed LOH at the p53 locus, relative to background epithelium. The LFS model confirms prior observations that the distal Fallopian tube is particularly prone to focal epithelial p53 gene inactivation-p53 mutation and LOH-in the absence of malignancy or increased epithelial proliferation. The fact that the LFS is not associated with ovarian cancers is consistent with the concept that loss of p53 function must be accompanied by at least one more genotoxic event (including BRCA1/2 functional inactivation) to produce the malignant phenotype. This is in keeping with a general model of carcinogenesis, in which different and often independent risk factors operate at multiple points in the serous carcinogenic spectrum.

The emerging role of the distal Fallopian tube and p53 in pelvic serous carcinogenesis

In their paper in this issue of the Journal, Xian et al have analysed in detail the Fallopian tubes from two patients with Li-Fraumeni syndrome (germline TP53 mutation) in order to investigate further the possible role of p53 signatures in the development of high-grade pelvic serous carcinoma. They find an increased frequency of p53 signatures, with associated evidence of DNA damage and loss of heterozygosity at the wild-type TP53 allele, but postulate, as Li-Fraumeni syndrome is not associated with an increased risk of pelvic serous carcinoma, that these events are not sufficient for the development of carcinoma. Rather, they put forward a model postulating that further events, particularly loss of BRCA1/2 function, are required for lesion progression. This paper exemplifies how the hypothesis-driven study of a rare syndrome can be highly effective at answering specific questions about disease processes. It is of note that recent evidence from the same group provides convincing evidence that the distal Fallopian tube may, in fact, be the commonest site of origin for high-grade pelvic serous carcinomas, most of which may originate at this site rather than from the ovary. In addition to its biological significance, this, if proven, has clear clinical implications.

Role of CSF-1 in progression of epithelial ovarian cancer

Despite the dismal outcome seen in the majority of epithelial ovarian cancer patients, there is ongoing progress in understanding the disease at a molecular level. Elucidation of pathways underlying disease progression and metastasis of ovarian cancer is key to development of targeted therapeutics. It is only in this way that therapeutic potential can be translated to reality. Here, we describe the evidence to date for the role of CSF-1/c-fms signaling in ovarian cancer invasiveness and metastasis, including the recent understanding of how CSF-1/c-fms expression is regulated with identification of significant post-transcriptional regulators.

HMGA2: a potential biomarker complement to P53 for detection of early-stage high-grade papillary serous carcinoma in fallopian tubes

Before high-grade papillary serous carcinoma (HG-PSC) becomes invasive, it is believed to be a poorly defined short-lived precursor lesion. A recent characterization of serous tubal intraepithelial carcinoma (STIC) and of the p53 signature suggested that HG-PSC may follow a stepwise progression on cellular and molecular levels. High-mobility group AT-hook 2 (HMGA2), an oncofetal protein, is overexpressed in ovarian cancer. To test whether HMGA2 can be another valuable marker for STIC, we examined HMGA2 expression in 3 groups of patients: (1) 24 patients with STIC and its invasive counterpart, HG-PSC of the fallopian tubes, (2) 24 patients with HG-PSC of the ovaries but without STIC (positive control), and (3) 30 patients with cancer and normal fallopian tubes (negative control). We found that HMGA2 was overexpressed in 75% of patients with STIC, was coexpressed with p53 in more than 50% of patients, and was completely negative in the secretory cells of the 30 patients with normal fallopian tubes. Among 7 patients with cells negative for p53 staining, HMGA2 was positive in 5; among 6 patients whose tumor cells were negative for HMGA2 in STIC, 3 were positive for HMGA2 in the invasive component; about 70% of invasive HG-PSC tumor cells were immunoreactive for both HMGA2 and TP53. In invasive carcinoma, HMGA2 overexpression was correlated with p53 (r=0.45), indicating the role of HMGA2 in p53 mediated tumor progression. Our findings of immunoreactivity for HMGA2 may lead to a novel, useful biomarker to complement p53 in the detection of early-stage serous carcinoma.

Proteogenomic studies in epithelial ovarian cancer: established knowledge and future needs

There has been a concerted effort over the last decade to improve our understanding of the complex biology of ovarian cancer. A linear growth in published proteogenomic studies has addressed a variety of questions regarding its molecular pathogenesis. A number of genes have been identified by transcriptomic approaches, some of which are being investigated as putative tumor markers (HE4, OPN, Ep-CAM and Mesothelin), whilst others are potential targets for molecular therapeutic approaches (VEGF, IO4, EGFR, MUC1, CLDN4 and SLPI). Proteogenomics has the potential to further change our current characterization and treatment of ovarian cancer. Additional advances will depend on integrated study designs, interdisciplinary collaborations, use of robust high-throughput platforms, as well as uniform guidelines for bioinformatic analyses.

Recent advances in molecular gynaecological pathology

This review gives an overview of recent advances in our understanding of the molecular basis of gynaecological malignancy, including cervical, vulval, endometrial and ovarian tumours. These advances are beginning to influence clinical practice, perhaps most notably with the introduction of human papillomavirus vaccination for the prevention of anogenital neoplasia, but are likely to have broader clinical implications as further details emerge.

Precursors of endometrial and ovarian carcinoma

This review discusses precursor lesions of endometrial and ovarian carcinoma with an emphasis on the unique molecular alterations that have led to the development of binary classification schemes for tumors of both the endometrium and ovary. While such a system is well established for endometrial carcinoma, only recently has a binary classification scheme been proposed for ovarian carcinoma. For both, the morphologic and molecular genetic-defining characteristics of their respective precursor lesions are described in detail. Furthermore, similarities and differences of the precursor lesions of specific tumors of these two genital tract organs are also addressed with a brief discussion of the clinical implications of their diagnosis.

Candidate serous cancer precursors in fallopian tube epithelium of BRCA1/2 mutation carriers

Occult invasive and intraepithelial carcinomas have been identified in the tubal fimbria of BRCA mutation carriers undergoing prophylactic surgery, and recently described lesions overexpressing p53 in the distal tubes of mutation carriers, and non-carriers, have been proposed as histological precursors of high-grade serous carcinoma. The aim of this study was to confirm these findings in a larger, independent case set, to further characterize the cancer precursor lesions, and to determine their frequency in BRCA mutation-positive (n=176) and control groups (n=64). For the purposes of this study, we excluded cases without documentation of a germline mutation of BRCA1/2, and without histological examination of the entire tube, and cases with a diagnosis of invasive carcinoma. Controls included salpingectomies from women undergoing surgery for reasons other than ovarian malignancy. Diagnostic categories were assigned based on combined histological review and immunostaining results. Histological abnormalities were identified in 23% of the BRCA group and in 25% of the control group, and included localized p53 overexpression in 20% of the BRCA group and 25% of the control group. Tubal intramucosal carcinoma was identified in 8% of the BRCA cases and in 3% of the control group. Four cases of intraepithelial carcinoma (21%) did not overexpress p53. There was no significant difference in the median age, frequency of histological abnormalities, p53 signatures, or tubal intraepithelial carcinoma between the BRCA mutation-positive and control groups. This large, blinded review of tubes from BRCA mutation carriers confirms previous reports of putative cancer precursors in distal tubal mucosa, and that p53 signatures occur with similar frequency in women at low and high genetic risk of tubal/ovarian carcinoma. Tubal intraepithelial carcinoma, which, like invasive serous cancer, usually but not always overexpresses p53 protein, is more frequent in BRCA mutation carriers.

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.

Insights into selected genetic diseases affecting the female reproductive tract and their implication for pathologic evaluation of gynecologic specimens

CONTEXT

Recent advances in the understanding of genetic conditions involving the female genital tract and mechanisms of carcinogenesis in this setting affect patient management and thus necessitate appropriate pathologic evaluation of specimens. In the past, specimens from prophylactic surgery were a rarity; however, they are now more frequently encountered and often require a significant variation from routine processing methods. Pathologists also receive more specimens requiring prospective workup for possible underlying genetic conditions such as microsatellite instability.

OBJECTIVE

To summarize the current knowledge of important genetic and hereditary conditions affecting the female reproductive organs while highlighting the resulting practical significance for specimen handling, "grossing," and microscopic evaluation in gynecologic pathology.

DATA SOURCES

This update is based on a review of recent peer-reviewed literature and the experience with cases at the parent institutions.

CONCLUSIONS

Gynecologic specimens received from patients with certain genetic conditions require specific clinicopathologic knowledge for appropriate pathologic examination. The evaluation of prophylactic resection specimens focuses on the detection of cancer precursors and possible occult disease, which may require a more thorough and detailed examination than an obvious carcinoma. Standardized protocols for handling prophylactic gynecologic resection specimens are available for some, but not all, types of specimens. The prospective evaluation of a gynecologic pathology specimen for potential genetic conditions such as microsatellite instability is a very recent subject. Currently, well-established protocols are not available; however, as clinical and prognostic significance has become more clearly elucidated, familiarity with this evolving field is increasingly important to properly assess these pathologic specimens.

Ovarian carcinoma pathology and genetics: recent advances

In this review we summarize recent advances in the histopathological diagnostic criteria and molecular pathology of the main subtypes of ovarian surface epithelial carcinoma. These advances have greatly improved our understanding of the biology of ovarian carcinoma and are also relevant to patient management. With progress toward subtype-specific treatment of ovarian carcinoma, accurate, reproducible histopathological diagnosis of these subtypes by practicing pathologists is increasingly important.

Beyond CA125: the coming of age of ovarian cancer biomarkers. Are we there yet?

Ovarian cancer (OC) is the fourth leading cause of cancer deaths among women in the United States, despite its relatively low incidence of 50 per 100,000. Even though advances in therapy have been made, the OC fatality-to-case ratio remains exceedingly high, due to the lack of accurate tools to diagnose early-stage disease when cure is still possible. The most studied marker for OC, CA125, is only expressed by 50-60% of patients with early stage disease. Large efforts have been deployed to identify novel serum markers, yet no single marker has emerged as a serious competitor for CA125. Various groups are investing in combination approaches to increase the diagnostic value of existing markers, but many markers may still lie in under-explored areas of ovarian cancer biology, such as tumor vasculature environment and post-translational modifications (glycomics).

Analysis of gene expression in stage I serous tumors identifies critical pathways altered in ovarian cancer

OBJECTIVE

Despite recent advances in the conceptual understanding of the pathogenesis of ovarian cancer, it remains the foremost cause of death from gynecologic malignancies in developed countries. The main reason for such a high rate of mortality is the lack of sensitive and specific biomarkers and imaging techniques for early detection of ovarian cancer. Additional biological insights into early-stage ovarian carcinogenesis are needed to help speed the development of markers for early detection of ovarian cancer. The objective of this study was to characterize differentially expressed genes in high-grade stage I serous carcinoma of the ovary.

METHODS

We analyzed gene expression in macrodissected formalin-fixed, paraffin-embedded samples from 5 high-grade stage I serous carcinomas and 5 stage I borderline tumors of the ovary using the Illumina Whole Genome DASL assay (cDNA-mediated annealing, selection, extension, and ligation) corresponding to 24,000 genes. Significance Analysis of Microarrays was performed to determine differentially expressed genes in stage I serous carcinoma, and class prediction analysis was performed to determine the predictive value of differentially expressed gene sets to correctly classify serous carcinoma from borderline tumors in 3 independent data sets. Altered transcription factor pathways and biological pathways unique to stage I serous carcinoma were identified through class comparison of differentially expressed genes.

RESULTS

Unsupervised cluster analysis of gene expression correctly classified stage I serous carcinomas from serous borderline tumors. Supervised analysis identified several known, as well as novel, genes differentially expressed in stage I ovarian cancer. Using a differentially expressed gene set, class comparison prediction analysis correctly identified serous carcinomas from serous borderline tumors in 3 independent data sets at over 80% accuracy, sensitivity, and specificity. Pathway analysis demonstrated the significance of p53 and E2F pathways in serous carcinogenesis and significant involvements of cell cycle and immune response pathways in stage I serous epithelial ovarian cancer.

CONCLUSION

We have identified differentially expressed genes associated with the carcinogenesis of high-grade stage I serous EOC. Furthermore, integrative analysis of biological and transcription pathway data contributed to the confirmation of important biological pathways and discovery of additional unique genes and pathways that may have potential importance in ovarian pathogenesis and biomarker development.

Intercepting pelvic cancer in the distal fallopian tube: theories and realities

The pathogenesis of high-grade serous carcinoma of the ovary has come into sharper focus as closer attention has been paid to the earlier phases of this disease. The study of patients with BRCA mutation has been of particular value, in as much as the examination of prophylactic salpingo-oophorectomies will reveal an early cancer in approximately 5% of individuals. Recently studies have shown that about 80% of these early carcinomas originate in the distal fallopian tube. This review summarizes the recent data supporting the distal fallopian tube as an important site for serous carcinogenesis, stressing both the presence of a novel precursor (the p53 signature) and the application of this model to all women irrespective of BRCA status. The challenges and unmet needs unmasked by this paradigm shift in ovarian cancer research are discussed.

Hereditary ovarian carcinoma: heterogeneity, molecular genetics, pathology, and management

Hereditary ovarian cancer accounts for at least 5% of the estimated 22,000 new cases of this disease during 2009. During this same time, over 15,000 will die from malignancy ascribed to ovarian origin. The bulk of these hereditary cases fits the hereditary breast-ovarian cancer syndrome, while virtually all of the remainder will be consonant with the Lynch syndrome, disorders which are autosomal dominantly inherited. Advances in molecular genetics have led to the identification of BRCA1 and BRCA2 gene mutations which predispose to the hereditary breast-ovarian cancer syndrome, and mutations in mismatch repair genes, the most common of which are MSH2 and MLH1, which predispose to Lynch syndrome. These discoveries enable relatively certain diagnosis, limited only by their variable penetrance, so that identification of mutation carriers through a comprehensive cancer family history might be possible. This paper reviews the subject of hereditary ovarian cancer, with particular attention to its molecular genetic basis, its pathology, and its phenotypic/genotypic heterogeneity.

Expression of ovarian tumour suppressor OPCML in the female CD-1 mouse reproductive tract

Opioid binding protein/cell adhesion molecule-like gene (OPCML) is frequently inactivated in epithelial ovarian cancer, but the role of this membrane protein in normal reproductive function is unclear. The ovarian surface epithelium (OSE) is thought to be the cell of origin of most epithelial ovarian cancers, some of which arise after transformation of OSE cells lining ovarian inclusion cysts, formed during ovulation. We used immunohistochemistry, immunoblotting and quantitative RT-PCR (qRT-PCR) to investigate OPCML expression in the uteri and ovaries of cycling 3-month CD-1 mice, as well as in ovaries from older mice containing inclusion cysts derived from rete ovarii tubules. Immunoblotting showed OPCML bands in uterine, but not whole ovarian or muscle extracts. Strong OPCML immunoreactivity was observed in oviduct, rete ovarii and uterus, whereas in ovary more immunoreactivity was seen in granulosa cells than OSE. No staining was observed in OSE around ovulation sites, where OSE cells divide to cover the site. OPCML immunoreactivity was also weaker in more dysplastic cells lining large ovarian inclusion cysts, compared with normal rete ovarii. No significant changes in Opcml mRNA expression were observed in whole ovarian and uterine extracts at different stages of the cycle. We conclude that murine OPCML is more consistently expressed in cells lining the uterus, oviduct and rete ovarii than in ovary and is not expressed in OSE associated with ovulation sites. This observation supports the hypothesis that a proportion of epithelial ovarian cancers arise from ductal cells and other epithelia of the secondary Mullerian system, rather than the OSE.

Evidence for a latent precursor (p53 signature) that may precede serous endometrial intraepithelial carcinoma

Both serous intraepithelial carcinoma and endometrial glandular dysplasia are associated with uterine serous carcinoma. Recently a candidate serous cancer precursor containing p53 mutations (p53 signature) was described in the fallopian tube. We analyzed normal and neoplastic endometrium for a similar entity. In total 10 endometrial polyps involved by intraepithelial and/or invasive carcinoma and 137 benign polyps were studied. All were stained for p53 and MIB-1. A subset of p53 signatures and carcinomas were analyzed for gamma-H2AX and p53 mutations. p53 signatures were identified in 7 of 10 cases intraepithelial carcinoma and were multicentric in 2. In one case, the signature was in continuity with intraepithelial carcinoma. Of 137 benign polyps (4%), 6 contained p53 signatures. The MIB-1 fraction in most signatures was less than 5%, and ranged from 50 to 90% in carcinomas. DNA damage (gamma-H2AX) was demonstrated in both p53 signatures and adjacent carcinomas but not in benign polyps. Shared identical p53 mutations were found in paired signatures and carcinomas in two of three cases analyzed, including one case with multiple signatures. In one, a coexistent invasive serous cancer was not found to contain a p53 mutation. In a third, a p53 signature and an invasive cancer harbored two different p53 mutations. This is the first description of p53 signatures adjacent to carcinoma, suggesting a role for this entity in the genesis of serous malignancy. The significance of p53 signatures in benign conditions (polyps) remains to be determined. The role of the p53 signature in early serous neoplasia is discussed.

Precursors to pelvic serous carcinoma and their clinical implications

Pelvic serous carcinoma has traditionally been viewed as a rapidly evolving malignancy, due principally to its late stage at diagnosis and tendency for poor outcome, both in the endometrium and the upper genital tract. Recently, studies of women with BRCA1 or BRCA2 mutations (BRCA+) undergoing risk reducing salpingo-oophorectomy have highlighted the distal fallopian tube as a common (80%) site of tumor origin and additional studies of unselected women with pelvic serous carcinoma have demonstrated that serous tubal intraepithelial carcinoma may precede a significant percentage of these tumors. This review examines the serous carcinogenic spectrum in the fallopian tube, highlighting recent evidence that these tumors may follow a defined precursor that has been present for a prolonged interval. The data supporting a candidate precursor, the implications of these findings for early detection and prevention of pelvic serous carcinoma and the caveats, are discussed.

Ovarian cancer: a clinical challenge that needs some basic answers

Kate Lawrenson and Simon Gayther discuss two studies of ovarian cancer inPLoS Medicine, one on clinico-pathological heterogeneity and one on gene expression profiling.

Low-grade serous carcinoma of the ovary displaying a macropapillary pattern of invasion

Invasive micropapillary serous carcinoma (MPSC) also designated "low-grade serous carcinoma" (LGSC) of the ovary is characterized by small micropapillae that infiltrate underlying tissue (ovarian stroma). On occasion these tumors in addition to the micropapillae contain large macropapillae lined by bland epithelium. In rare cases, the entire tumor is composed of macropapillae. In these cases, the question of whether this is an invasive carcinoma or an unusual type of adenofibroma has been raised. The goal of this study was to describe this unusual macropapillary pattern of invasion in LGSC. Cases of LGSC containing macropapillae were retrieved from the files of the Johns Hopkins Hospital. In addition to a detailed morphologic analysis, the mutational status of KRAS and BRAF in the macropapillary, noninvasive, and invasive MPSC components was analyzed by nucleotide sequencing. There were 14 cases containing macropapillae (11 cases of LGSC, 2 cases of atypical proliferative serous tumor (APST) with microinvasion, and 1 case of APST with a focus of LGSC with macropapillae in perivaginal soft tissue). In 3 cases, extraovarian metastases contained macropapillae. Molecular analysis of the primary tumor components (macropapillary, noninvasive, and invasive MPSC and/or APST) was performed in 7 cases and of a lymph node metastasis with macropapillae in 1 case. The identical KRAS mutation was detected in all of the analyzed components of the primary ovarian tumors in 4 cases. In one of these cases, macropapillae in the lymph node metastasis contained a KRAS mutation identical to the primary tumor. The BRAF mutation identified in 1 case was identical in all components of the ovarian tumor. The identical mutations in the macropapillae and the other tumor components in each case indicate that they are clonally related. The finding of macropapillae within lymph nodes supports the interpretation that the macropapillary component is another manifestation of invasion in LGSC. The recognition of this pattern is important, especially in cases when a tumor is composed entirely of macropapillae.

New insights into the pathogenesis of serous ovarian cancer and its clinical impact

There are only a handful of concepts concerning cancer and carcinogenesis that are currently beyond dispute. One such dogma is the adenoma-carcinoma sequence and that a multistep accumulation of genetic alterations is required for transformation from a benign to a neoplastic tissue. The inevitable derivative of this dogma is that every invasive carcinoma is in fact a missed intraepithelial tumor, and furthermore, a late evolutionary stage in the sequence of development from a precursor lesion. Until fairly recently, high-grade serous ovarian carcinoma seemed to be one of the only known deviants of these concepts. In this article, we discuss the emergence of the fallopian tube fimbria as a field of origin for high-grade serous carcinomas and present a binary model of ovarian cancer pathogenesis that takes into consideration prior epidemiologic, morphologic, and genetic data. With the rise of the fallopian tube secretory epithelial cell as a cell of origin for high-grade pelvic serous carcinomas, the need to develop tools and model systems to characterize the biology and physiology of this cell is recognized.