Risk of nonovarian cancer in a nationwide-based study of nearly 5000 women with borderline ovarian tumors in Denmark.

Evidence regarding cancer risk after borderline ovarian tumors (BOTs) is limited. We conducted a nationwide cohort study examining the incidence of nonovarian cancers in women with serous or mucinous BOTs compared with the general female population with up to 41 years of follow-up. Through the nationwide Pathology Registry, we identified nearly 5000 women with BOTs (2506 serous and 2493 mucinous) in Denmark, 1978 to 2018. We computed standardized incidence ratios (SIRs) with 95% confidence intervals (CIs) as relative risk estimates of specific nonovarian cancers. Compared with general female population rates, women with serous BOTs had increased rates of particularly malignant melanoma (SIR = 1.9; 95% CI: 1.3-2.6), thyroid cancer (SIR = 3.0; 95% CI: 1.4-5.4) and myeloid leukemia (SIR = 3.2; 95% CI: 1.5-5.8), and women with mucinous BOTs had elevated rates of lung cancer (SIR = 1.7; 95% CI: 1.3-2.1), pancreatic cancer (SIR = 1.9; 95% CI: 1.2-2.9) and myeloid leukemia (SIR = 2.3; 95% CI: 0.9-4.7). We found no convincing association with neither breast nor colorectal cancer in women with BOTs. This is the first large nationwide study showing that women with specific types of BOTs have increased risks of several nonovarian cancers, likely due to some shared risk factors or genetic characteristics.

Risk of specific types of ovarian cancer after borderline ovarian tumors in Denmark: A nationwide study.

Population-based evidence regarding risk of ovarian cancer after a borderline ovarian tumor (BOT) is sparse. We aimed to examine the incidence of specific types of ovarian cancer in women with serous or mucinous BOTs in a nationwide cohort study with up to 36 years of follow-up. Using the nationwide Danish Pathology Data Bank, we identified 4,281 women with a BOT (2,058 serous BOTs and 2,223 mucinous BOTs) in Denmark during 1978-2012. We computed standardized incidence ratios (SIRs) to compare the incidence of ovarian cancer among women with BOTs compared to general population rates. We found that a serous BOT was especially and strongly associated with subsequent serous ovarian cancer (SIR = 9.2; 95% CI: 6.8-12.2), and that a mucinous BOT was strongly related to mucinous ovarian cancer (SIR = 18.6; 95% CI: 10.8-29.8). The SIRs remained elevated ≥10 years after a serous BOT and up to 5-9 years after a mucinous BOT. The increased incidence of serous ovarian cancer in women with a serous BOT was mostly pronounced in women <50 years at the serous BOT diagnosis. In conclusion, women with a serous BOT experience long-term increased incidence of serous ovarian cancer, and women with a mucinous BOT have long-term elevated incidence of mucinous ovarian cancer compared to the general population. This is the first population-based study to show compelling evidence of the histo-specific increased risk of ovarian cancer following specific types of BOTs. Thus, these results are supportive of the hypothesis that BOTs may be precursor lesions to carcinomas of the corresponding histologic type.

Two types of primary mucinous ovarian tumors can be distinguished based on their origin.

The origin of primary mucinous ovarian tumors is unknown. We explore the hypothesis that they originate from either Brenner tumors or teratomas and examine differences between the tumors that arise in these settings. A total of 104 Brenner tumor-associated mucinous tumors and 58 teratoma-associated mucinous tumors were analyzed. Immunohistochemistry for 21 antigens and fluorescence in situ hybridization for ERBB2 and MYC were performed. Genome-wide copy number analysis and mutation analysis for 56 cancer-related genes was carried out on a subset of mucinous ovarian tumors and their complementary Brenner tumor or teratoma. Patients with teratoma-associated mucinous tumors were significantly younger than patients with Brenner tumor-associated mucinous tumors (43 vs. 61 years). During progression from cystadenoma to atypical proliferative mucinous (borderline) tumor to carcinoma expression of typical gastrointestinal markers was increased in both Brenner tumor-associated and teratoma-associated mucinous tumors. Brenner tumor-associated mucinous tumors showed more frequently calcifications and Walthard cell nests, rarely expressed SATB2 and showed more often co-deletion of CDKN2A and MTAP. Teratoma-associated mucinous tumors were characterized by mucinous stromal dissection, SATB2 expression and RNF43 mutations. Other frequent mutations in both Brenner tumor-associated and teratoma-associated mucinous tumors were TP53 and KRAS mutations. Based on identical mutations or copy number profiles clonal relationships were indicated in two mucinous tumors and their associated Brenner tumor. Teratomas and Brenner tumors give rise to different subtypes of mucinous ovarian tumors. Subsequent progression pathways are comparable since both Brenner tumor-associated and teratoma-associated mucinous tumors develop a gastrointestinal immunophenotype during progression and show early mutations in KRAS and TP53. Teratoma-associated mucinous tumors may more closely resemble true gastrointestinal tumors, indicated by their expression of SATB2 and the presence of RNF43 mutations.

Intratumoral Heterogeneity Accounts for Apparent Progression of Noninvasive Serous Tumors to Invasive Low-grade Serous Carcinoma: A Study of 30 Low-grade Serous Tumors of the Ovary in 18 Patients With Peritoneal Carcinomatosis.

Noninvasive ovarian low-grade serous tumors [atypical proliferative serous tumor (APST)/serous borderline tumor] appear to progress to invasive low-grade serous carcinoma (LGSC) at a low but regular rate. The underlying biology of this phenomenon is unknown. We studied 18 patients with 30 ovarian tumors (12 bilateral), including APST, noninvasive LGSC and invasive LGSC, who also had low-grade serous carcinomatosis. Tumors were evaluated for microinvasion (usual eosinophilic cell type), microinvasive carcinoma (<5 mm invasion of micropapillary nests), and overt carcinoma (≥5 mm invasion of micropapillary nests). Tumors were evaluated based on the original numerical order of sections under the hypothetical scenarios in which sampling was stopped at 1 section/cm and 2 sections/cm. Sampling based on 1 section/cm of greatest tumor dimension identified invasion of any type in 21 tumors (70%). Among these 21 tumors, 10 had microinvasive carcinoma, and 11 overt carcinoma. Sampling based on 2 sections/cm identified microinvasive carcinoma in 9 tumors and overt carcinoma in 14 tumors. With increased sampling from 1 to 2 sections/cm, the diagnosis in 3 tumors would have changed from microinvasive carcinoma to overt carcinoma, and in an additional 2 tumors from APST to APST with microinvasive carcinoma. Sampling based on >2 sections/cm changed the diagnosis in 1 additional case of APST with microinvasive carcinoma to overt carcinoma. These findings support that undetected (unsampled) occult invasion in the primary ovarian tumors is a likely explanation for some cases of apparent progression of noninvasive low-grade serous ovarian tumors to invasive LGSC. To minimize undetected occult invasion, consideration of sampling noninvasive low-grade ovarian serous tumors with at least 2 sections/cm of maximum tumor diameter may be warranted. The eosinophilic cell type of microinvasion, or microinvasive carcinoma, regardless of size, should prompt further sampling to identify overt carcinoma. The eosinophilic type of microinvasion was never seen alone in this cohort and by itself may be biologically insignificant.

Genomic landscape and evolutionary trajectories of ovarian cancer precursor lesions.

The clonal relationship between ovarian high-grade serous carcinoma (HGSC) and its presumed precursor lesion, serous tubal intraepithelial carcinoma (STIC), has been reported. However, when analyzing patients with concurrent ovarian carcinoma and tubal lesion, the extensive carcinoma tissues present at diagnosis may have effaced the natural habitat of precursor clone(s), obscuring tumor clonal evolutionary history, or may have disseminated to anatomically adjacent fimbriae ends, masquerading as precursor lesions. To circumvent these limitations, we analyzed the genomic landscape of incidental tubal precursor lesions including p53 signature, dormant STIC or serous tubal intraepithelial lesion (STIL) and proliferative STIC in women without ovarian carcinoma or any cancer diagnosis using whole-exome sequencing and amplicon sequencing. In three of the four cancer-free women with multiple discrete tubal lesions we observed non-identical TP53 mutations between precursor lesions from the same individual. In one of the four women with co-existing ovarian HGSC and tubal precursor lesion we found non-identical TP53 mutations and a lack of common mutations shared between her precursor lesion and carcinoma. Analyzing the evolutionary history of multiple tubal lesions in the same four patients with concurrent ovarian carcinoma indicated distinct evolution trajectories. Collectively, the results support diverse clonal origins of tubal precursor lesions at the very early stages of tumorigenesis. Mathematical modeling based on lesion-specific proliferation rates indicated that p53 signature and dormant STIC may take a prolonged time (two decades or more) to develop into STIC, whereas STIC may progress to carcinoma in a much shorter time (6 years). The above findings may have implications for future research aimed at prevention and early detection of ovarian cancer. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Nine-valent HPV vaccine efficacy against related diseases and definitive therapy: comparison with historic placebo population.

OBJECTIVE: Nine-valent human papillomavirus (9vHPV) vaccine efficacy against disease and cervical surgeries related to all nine vaccine components was assessed compared with a historic placebo population. This was not assessed in the 9vHPV vaccine efficacy trial since the trial was quadrivalent HPV (qHPV) vaccine-controlled, efficacy was measured for the five HPV types covered only by 9vHPV vaccine (HPV31/33/45/52/58), but not the four types covered by both vaccines (HPV6/11/16/18). METHODS: Three international, randomized, double-blind studies were conducted using the same methodology. In the 9vHPV vaccine study (NCT00543543), 7106 and 7109 women received 9vHPV or qHPV vaccine, respectively. In the historic qHPV vaccine studies (FUTURE I [NCT00092521] and II [NCT00092534]), 8810 and 8812 women received qHPV vaccine or placebo, respectively, based on the same eligibility criteria. Cervical cytological testing was performed regularly. Biopsy or definitive therapy specimens were assessed for HPV DNA. RESULTS: Among women negative for 14 HPV types prior to vaccination, incidence of high-grade cervical disease (9vHPV, n = 2 cases; placebo, n = 141 cases) and cervical surgery (9vHPV, n = 3 cases; placebo, n = 170 cases) related to the nine HPV types was reduced by 98.2% (95% confidence interval [CI], 93.6-99.7) and 97.8% (95% CI, 93.4-99.4), respectively. The 9vHPV vaccine did not prevent disease related to vaccine HPV types detected at baseline, but significantly reduced cervical, vulvar, and vaginal diseases related to other vaccine HPV types. CONCLUSIONS: Effective implementation of the 9vHPV vaccine may substantially reduce the burden of HPV-related diseases and related medical procedures. TRIAL REGISTRATIONS: clinicaltrials.gov: NCT00543543, NCT00092521, NCT00092534.

Comprehensive Surgical Staging in Stage 1 Clear Cell and Endometrioid Ovarian Carcinomas: Is it Necessary?

The objective of this article was to evaluate the presence of occult metastasis after comprehensive surgical staging of clear cell ovarian carcinoma (CCC) and endometrioid ovarian carcinoma (EMCA) that appeared to be confined to the ovary at time of surgery. Between 1998 to 2016, 85 patients with CCC and EMCA were identified who were comprehensively staged and felt to be stage 1 intraoperatively. Of the 85 patients who underwent surgical staging, 4 (4.7%) had omental and dense pelvic side-wall tumor adhesions. On final pathology, 67 (79%) patients were diagnosed as stage 1A of which 29 (43%) patients were upstaged to 1C1 due to intraoperative rupture. The remaining 18 (21%) patients were staged as 1C2/1C3. The 1- and 5-yr disease-free survival for pathology stage 1A tumors was 94% and 76%, respectively, and for 1C2/1C3 tumors was 100% and 75%, respectively. Among patients who received adjuvant chemotherapy, the 5-yr disease-free survival was near equal for pathology stage 1A and 1C2/1C3 groups (73% vs. 74%), with a lower 5-yr disease-free survival for CCC compared with EMCA (72% vs. 78%). There were 16 (19%) recurrences with 12 being pathology stage 1A. Of these 12 patients, 9 (75%) had CCC of which 2 received adjuvant chemotherapy. Even in the presence of dense adhesions (4.7%), the likelihood of extraovarian disease in CCC and EMCA confined to the ovary was very low. Accordingly, the findings in this study indicate that comprehensive surgical staging for what appears to be stage 1 CCC and EMCA may provide no benefit in detecting occult disease that would upstage the tumor.

Atypical Proliferative (Borderline) Serous Tumor in the Brain: A Case Report.

A 59-year-old woman with a remote history of invasive ductal carcinoma of the breast was found on a follow-up computed tomography scan of her brain to have a 1-cm lesion in the right frontal lobe in 2008. In the ensuing years, before her current admission, multiple imaging studies of the brain revealed that the lesion was stable and it was, therefore, interpreted as a small area of encephalomalacia related to a thrombosed cortical vein, a cavernoma, or treated metastatic breast cancer. In 2013, the patient underwent a bilateral salpingo-oophorectomy for ovarian tumors that were diagnosed as bilateral serous cystadenofibromas. A partial omentectomy showed no evidence of implants. In June 2016, the brain lesion was completely excised and diagnosed as an atypical proliferative (borderline) serous tumor. Immunohistochemical staining demonstrated that the tumor cells were immunoreactive for Pax8, WT-1, ER, and CK-7 and negative for Gata-3, PR, TTF-1, CDX-2, Napsin A, and CK-20, which was consistent with that diagnosis. We present a brief review of possible mechanisms to account for this unusual presentation and speculate that the most likely one is exfoliation of fallopian tube epithelial cells into the peritoneal cavity, which then gain access to lymphatics resulting in cells implanting in the brain and subsequently progressing to an atypical proliferative (borderline) serous tumor.

Steroid hormone synthesis by the ovarian stroma surrounding epithelial ovarian tumors: a potential mechanism in ovarian tumorigenesis.

Epithelial ovarian tumors are responsive to steroid hormone stimulation and the ovarian stroma may have a direct role in this process. We evaluated immunohistochemical markers of sex-steroid differentiation and steroidogenesis (calretinin, inhibin, steroidogenic factor 1), steroid enzymes involved in hormone biosynthesis (CYP17, CYP19, HSD17ß1, AKR1C3), and hormone receptors (estrogen receptor, progesterone receptor, and androgen receptor) in 101 epithelial ovarian tumors and in normal structures implicated in ovarian carcinogenesis (ovarian surface epithelium and cortical inclusion cysts) in an attempt to elucidate this process. We hypothesized that ovarian stroma immediately adjacent to tumors express markers of sex-steroid differentiation and steroidogenesis and steroid enzymes whereas the epithelium contains corresponding hormone receptors. As the findings in seromucinous, endometrioid, and clear cell neoplasms, tumors closely associated with endometriosis, were very similar, these were combined into a group designated 'endometriosis-related tumors.' Significantly increased expression of markers of sex-steroid differentiation and steroidogenesis was found in stroma immediately adjacent to endometriosis-related tumors (P=0.003) and mucinous tumors (primary and metastatic mucinous tumors were combined because of similar findings) (P<0.0001) compared with more remote ovarian stroma. In addition, sex-steroid enzymes were increased in stroma adjacent to endometriosis-related tumors (P=0.02) and mucinous tumors (P=0.02) compared with more distant stroma. Steroid hormone receptors showed greater expression in epithelium compared with stroma in the endometriosis-related tumors (P=0.0009), low-grade serous tumors (P<0.0001), and high-grade serous carcinoma (P=0.0036). In contrast, there was greater expression in stroma compared with epithelium (P<0.0001) in mucinous tumors, which may be due to the fact that they are not derived from müllerian epithelium. In conclusion, our findings strongly support the view that the stroma surrounding epithelial tumors in the ovary is activated to elaborate steroid hormones which may stimulate further neoplastic growth. The precise mechanisms by which this process might occur are complex and require further investigation.

The Dualistic Model of Ovarian Carcinogenesis: Revisited, Revised, and Expanded.

Since our proposal of a dualistic model of epithelial ovarian carcinogenesis more than a decade ago, a large number of molecular and histopathologic studies were published that have provided important insights into the origin and molecular pathogenesis of this disease. This has required that the original model be revised and expanded to incorporate these findings. The new model divides type I tumors into three groups: i) endometriosis-related tumors that include endometrioid, clear cell, and seromucinous carcinomas; ii) low-grade serous carcinomas; and iii) mucinous carcinomas and malignant Brenner tumors. As in the previous model, type II tumors are composed, for the most part, of high-grade serous carcinomas that can be further subdivided into morphologic and molecular subtypes. Type I tumors develop from benign extraovarian lesions that implant on the ovary and which can subsequently undergo malignant transformation, whereas many type II carcinomas develop from intraepithelial carcinomas in the fallopian tube and, as a result, disseminate as carcinomas that involve the ovary and extraovarian sites, which probably accounts for their clinically aggressive behavior. The new molecular genetic data, especially those derived from next-generation sequencing, further underline the heterogeneity of ovarian cancer and identify actionable mutations. The dualistic model highlights these differences between type I and type II tumors which, it can be argued, describe entirely different groups of diseases.

A nationwide study of ovarian serous borderline tumors in Denmark 1978-2002. Risk of recurrence, and development of ovarian serous carcinoma.

OBJECTIVE: Absolute risk and risk factors for recurrence and ovarian serous carcinoma following ovarian serous borderline tumors (SBTs) is not well-established. METHODS: We included all women with SBTs in Denmark, 1978-2002. Diagnoses were confirmed by centralized pathology review and classified as atypical proliferative serous tumor (APST) or noninvasive low-grade serous carcinoma (LGSC). Implants were classified as noninvasive or invasive. Medical records were collected and reviewed, and follow-up was obtained. Subsequent diagnoses were also confirmed by centralized pathology review. We examined absolute risk and risk factors for recurrent APST and serous carcinoma using Cox regression. RESULTS: The absolute serous carcinoma risk after, respectively, 5 and 20years was 5.0% and 13.9% for noninvasive LGSC, and 0.9% and 3.7% for APST. Serous carcinoma risk was significantly higher following noninvasive LGSC compared with APST among stage I patients/patients without implants (HR=5.3; 95% CI: 1.7-16.3), whereas no significant association with tumor type was found in advanced stage patients/patients with implants. Advanced stage - notably invasive implants - bilaterality, surface involvement, and residual disease increased serous carcinoma risk. However, women with stage I APST also had a higher risk than the general population. CONCLUSIONS: This largest population-based cohort of verified SBTs revealed that women with noninvasive LGSC are significantly more likely to develop serous carcinoma than women with APST, which could not entirely be explained by invasive implants. Although invasive implants was a strong risk factor for serous carcinoma, even women with stage I APST were at increased risk compared with the general population.

Parity, infertility, oral contraceptives, and hormone replacement therapy and the risk of ovarian serous borderline tumors: A nationwide case-control study.

OBJECTIVE: Few studies have examined the risk of an ovarian serous borderline tumor (SBT) associated with parity, infertility, oral contraceptives (OCs), or hormone replacement therapy (HRT), which was the study aim. METHODS: This nationwide case-control study included all women with an SBT diagnosis in Denmark, 1978-2002. SBTs were confirmed by centralized expert pathology review. For each case, 15 age-matched female controls were randomly selected using risk-set sampling. Cases and controls with previous cancer (except for non-melanoma skin cancer) and controls with bilateral oophorectomy or salpingo-oophorectomy were excluded. Conditional logistic regression was used to estimate adjusted odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: We found a strongly decreased risk of SBTs among parous women which decreased with increasing number of children (p<0.01). Older age at first birth also decreased the SBT risk (p=0.03). An increased SBT risk was associated with infertility (OR=3.31; 95% CI: 2.44-4.49), which was present both among parous and nulliparous women. HRT use increased the SBT risk (OR=1.32; 95% CI: 1.02-1.72), whereas OC use decreased the risk (OR=0.40; 95% CI: 0.26-0.62). CONCLUSIONS: Our nationwide study with expert histopathologic review of all SBTs showed that parity, infertility, use of HRT, and use of OCs, respectively, were strongly associated with the risk of SBTs. This is the first study to report a strong and significantly decreased SBT risk associated with OC use and a significantly increased risk with infertility, and HRT use. This supports that SBTs and serous ovarian cancer share similar risk factors.

PD-L1 Expression in Human Placentas and Gestational Trophoblastic Diseases.

One of the major immune checkpoints responsible for immune evasion in cancer cells is the interaction between programmed cell death-1 (PD-1) and its ligand (PD-L1). As human trophoblastic cells display many of the features of malignant cells such as the ability to invade normal tissue including blood vessels and are apparently not eradicated by the host immune system, we undertook the present study to determine whether PD-L1 was upregulated in different types of trophoblastic cells during normal pregnancy and in gestational trophoblastic diseases. Immunohistochemistry using an anti-PD-L1-specific antibody demonstrated that in early and term normal placentas, PD-L1 was highly expressed in syncytiotrophoblast and to a much lower extent in intermediate trophoblastic cells located in the chorion laeve and implantation site. PD-L1 immunoreactivity was undetectable in cytotrophoblastic cells. This staining pattern in normal placenta was recapitulated in various types of gestational trophoblastic disease. PD-L1 was highly expressed by syncytiotrophoblast in complete moles and choriocarcinomas. The intermediate trophoblastic neoplasms, placental site trophoblastic tumors, and epithelioid trophoblastic tumors showed variable PD-L1 immunoreactivity but at a lower intensity than in the neoplastic syncytiotrophoblast in choriocarcinoma. In addition, we observed PD-1-positive lymphocytes located within the implantation site and in trophoblastic tumors. In summary, this study describes a novel mechanism for trophoblastic cells to create a tolerogenic feto-maternal interface by upregulating PD-L1 in syncytiotrophoblast and in intermediate trophoblast. Trophoblastic tumors may also use PD-L1 expression to evade the host immune response thereby promoting their survival.

CCNE1 amplification and centrosome number abnormality in serous tubal intraepithelial carcinoma: further evidence supporting its role as a precursor of ovarian high-grade serous carcinoma.

Aberration in chromosomal structure characterizes almost all cancers and has profound biological significance in tumor development. It can be facilitated by various mechanisms including overexpression of cyclin E1 and centrosome amplification. As ovarian high-grade serous carcinoma has pronounced chromosomal instability, in this study we sought to determine whether increased copy number of CCNE1 which encodes cyclin E1 and centrosome amplification (>2 copies) occurs in its putative precursor, serous tubal intraepithelial carcinoma. We found CCNE1 copy number gain/amplification in 8 (22%) of 37 serous tubal intraepithelial carcinomas and 12 (28%) of 43 high-grade serous carcinomas. There was a correlation in CCNE1 copy number between serous tubal intraepithelial carcinoma and high-grade serous carcinoma in the same patients (P<0.001). There was no significant difference in the percentage of CCNE1 gain/amplification between serous tubal intraepithelial carcinoma and high-grade serous carcinoma (P=0.61). Centrosome amplification was recorded in only 5 (14%) of 37 serous tubal intraepithelial carcinomas, and in 10 (40%) of 25 high-grade serous carcinomas. The percentage of cells with centrosome amplification was higher in high-grade serous carcinoma than in serous tubal intraepithelial carcinoma (P<0.001). Induced expression of cyclin E1 increased the percentage of fallopian tube epithelial cells showing centrosome amplification. Our findings suggest that gain/amplification of CCNE1 copy number occurs early in tumor progression and precedes centrosome amplification. The more prevalent centrosome amplification in high-grade serous carcinoma than in serous tubal intraepithelial carcinoma supports the view that serous tubal intraepithelial carcinoma precedes the development of many high-grade serous carcinomas.

Seromucinous Tumors of the Ovary. What's in a Name?

The recent 2014 World Health Organization (WHO) Classification of Tumours of the Female Reproductive Organs introduced a new category of ovarian neoplasm designated "seromucinous tumours". The recognition of this distinctive group of tumors is an important addition to the classification but the term "seromucinous" has serious flaws that obscures the nature of these neoplasms. Morphologically, seromucinous tumors in addition to serous and endocervical-type mucinous epithelium, contain endometrioid, indifferent and squamous type epithelium. Their immunoprofile is characterized by frequent expression of ER, PR, infrequent expression of WT1 and lack of expression of CK20 and CDX2, an immunostaining pattern consistent with a "müllerian" immunophenotype. Unlike serous and intestinal type mucinous tumors, seromucinous tumors are frequently associated with endometriosis making them more analogous to endometrioid and clear cell neoplasms. Indeed, recent studies have shown that a high proportion of seromucinous tumors lost expression of ARID1A, a tumor suppressor gene, that is mutated in approximately 50% of endometrioid and clear cell tumors, in sharp contrast to serous and intestinal-type mucinous tumors which do not contain ARID1A mutations or lose its expression. Therefore, based on their clinicopathologic, immunohistochemical and molecular genetic features we believe a more appropriate designation for this group of tumors is "mixed müllerian tumors" which can be subcategorized as "mixed müllerian cystadenomas", "mixed müllerian atypical proliferative (borderline) tumors" and "mixed müllerian carcinomas".

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

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

Clonality analysis of combined Brenner and mucinous tumours of the ovary reveals their monoclonal origin.

The derivation of ovarian intestinal-type mucinous tumours is not well established. Some are derived from teratomas but the origin of the majority is not clear. It has been recently proposed that the non-germ cell group may be derived from Brenner tumours, as the association of a mucinous tumour with a Brenner tumour is frequently observed. In order to explore the histogenesis of these neoplasms, we undertook a clonality analysis of the two components of ten combined Brenner and mucinous tumours using a human androgen receptor gene (HUMARA) assay. All eight informative cases of ten showed a concordant X-chromosome inactivation pattern between the two tumour components, indicative of a shared clonal origin (p = 0.0039). Microsatellite genotyping in five of the combined tumours displayed an identical heterozygous pattern with paired Fallopian tube tissue, indicative of a somatic cell origin. In addition, paired box protein 8, a highly sensitive Müllerian epithelial marker, was not detected by immunohistochemistry in either tumour component in any of the ten tumours, suggesting that this subset of mucinous tumours does not originate from Müllerian-derived epithelium. In conclusion, this study demonstrates that in combined mucinous and Brenner tumours, there is a shared clonal relationship between the two different tumour components and suggests that some pure mucinous tumours may develop from a Brenner tumour in which the Brenner tumour component becomes compressed and obliterated by an expanding mucinous neoplasm.

Loss of ALDH1A1 expression is an early event in the pathogenesis of ovarian high-grade serous carcinoma.

Tumor-initiating cells are thought to share features with normal somatic stem cells. In mice, stem cells at the ovarian hilum have been shown to express the stem cell marker, aldehyde dehydrogenase isoform 1A1 (ALDH1A1), and are prone to malignant transformation. The potential relevance of this finding to humans has not been established. In this study, we used immunohistochemistry to assess the distribution of ALDH1A1 staining in the epithelium of human fallopian tubes, with particular reference to the transition of tubal epithelium to mesothelium (ie, tubal-mesothelial junction), ovarian surface epithelium, as well as putative precursors of ovarian high-grade serous carcinoma, namely, serous tubal intraepithelial carcinoma and 'p53 signatures,' and overt serous carcinoma. Expression of ALDH1A1 was detected in both secretory and ciliated tubal epithelial cells, tubal-mesothelial junctions and ovarian surface epithelium, but was absent in serous tubal intraepithelial carcinoma and p53 signatures. Positive staining in high-grade serous carcinoma, when present, was typically limited to rare tumor cells. In silico analyses of the mRNA expression data set from The Cancer Genome Atlas revealed downregulation of ALDH1A1 transcripts in high-grade serous carcinoma relative to normal tubal epithelium, and no association between ALDH1A1 expression levels and overall survival. Our results do not support ALDH1A1 as a specific marker of stem cells in human fallopian tube and demonstrate that its loss of expression is an early event in the development of high-grade serous carcinoma.

Two types of ovarian cortical inclusion cysts: proposed origin and possible role in ovarian serous carcinogenesis.

Ovarian cortical inclusion cysts (CICs) have been long regarded as a possible site of origin of epithelial ovarian carcinoma. It has been proposed that they develop from invagination of ovarian surface epithelium (OSE) which then undergoes metaplasia to form mullerian-type tissue and then undergoes neoplastic transformation. Recent studies have challenged this view, at least for high-grade serous carcinoma, proposing that the latter arise from occult carcinomas in the fallopian tube. Although there is compelling evidence supporting this view, it does not account for the origin of all high-grade serous carcinomas. We have postulated that a subset of high-grade serous carcinoma may develop from CICs, but that they are derived from implantation of tubal epithelium when the OSE is disrupted at ovulation. If true, it would be expected that the number of CICs would increase with age and that CICs would not be present before menarche. To test this hypothesis we examined ovaries removed at autopsy for the presence of CICs and correlated their presence with age. In addition, we used immunohistochemistry for PAX8 (mullerian marker) and calretinin (mesothelial marker). CICs were defined as either ciliated (tubal-type, PAX8-positive) or flat (OSE-type, calretinin-positive). As it has been argued that steroid hormones convert mesothelial-derived OSE to mullerian-type tissue, we performed immunohistochemistry for estrogen and progesterone receptors. CICs lined by tubal-type epithelium were found only in postmenarchial women and 20/21 (95%) were PAX8-positive; none of the 5 flat cysts expressed PAX8 but 4/5 (80%) expressed calretinin. Estrogen receptor was expressed in 1 of 21 (5%) ciliated CICs, whereas it was negative in all 5 flat CICs. Progesterone receptor was expressed in 14 of 21 (66%) ciliated CICs, and in none of the 5 flat cysts. The findings suggest that there are 2 types of CICs, 1 from OSE and 1 from tubal epithelium that probably develop at the time of ovulation.

Mutational analysis of BRAF and KRAS in ovarian serous borderline (atypical proliferative) tumours and associated peritoneal implants.

There is debate as to whether peritoneal implants associated with serous borderline tumours/atypical proliferative serous tumours (SBT/APSTs) of the ovary are derived from the primary ovarian tumour or arise independently in the peritoneum. We analysed 57 SBT/APSTs from 45 patients with advanced-stage disease identified from a nation-wide tumour registry in Denmark. Mutational analysis for hotspots in KRAS and BRAF was successful in 55 APSTs and demonstrated KRAS mutations in 34 (61.8%) and BRAF mutations in eight (14.5%). Mutational analysis was successful in 56 peritoneal implants and revealed KRAS mutations in 34 (60.7%) and BRAF mutations in seven (12.5%). Mutational analysis could not be performed in two primary tumours and in nine implants, either because DNA amplification failed or because there was insufficient tissue for mutational analysis. For these specimens we performed VE1 immunohistochemistry, which was shown to be a specific and sensitive surrogate marker for a V600E BRAF mutation. VE1 staining was positive in one of two APSTs and seven of nine implants. Thus, among 63 implants for which mutation status was known (either by direct mutational analysis or by VE1 immunohistochemistry), 34 (53.9%) had KRAS mutations and 14 (22%) had BRAF mutations, of which identical KRAS mutations were found in 34 (91%) of 37 SBT/APST-implant pairs and identical BRAF mutations in 14 (100%) of 14 SBT/APST-implant pairs. Wild-type KRAS and BRAF (at the loci investigated) were found in 11 (100%) of 11 SBT/APST-implant pairs. Overall concordance of KRAS and BRAF mutations was 95% in 59 of 62 SBT/APST-implant (non-invasive and invasive) pairs (p < 0.00001). This study provides cogent evidence that the vast majority of peritoneal implants, non-invasive and invasive, harbour the identical KRAS or BRAF mutations that are present in the associated SBT/APST, supporting the view that peritoneal implants are derived from the primary ovarian tumour.