Serous Tubal Intraepithelial Carcinoma Lesions Research Articles

The genomic trajectory of ovarian high-grade serous carcinoma can be observed in STIC lesions.

Ovarian high-grade serous carcinoma (HGSC) originates in the fallopian tube, with secretory cells carrying a TP53 mutation, known as p53 signatures, identified as potential precursors. p53 signatures evolve into serous tubal intraepithelial carcinoma (STIC) lesions, which in turn progress into invasive HGSC, which readily spreads to the ovary and disseminates around the peritoneal cavity. We recently investigated the genomic landscape of early- and late-stage HGSC and found higher ploidy in late-stage (median 3.1) than early-stage (median 2.0) samples. Here, to explore whether the high ploidy and possible whole-genome duplication (WGD) observed in late-stage disease were determined early in the evolution of HGSC, we analysed archival formalin-fixed paraffin-embedded (FFPE) samples from five HGSC patients. p53 signatures and STIC lesions were laser-capture microdissected and sequenced using shallow whole-genome sequencing (sWGS), while invasive ovarian/fallopian tube and metastatic carcinoma samples underwent macrodissection and were profiled using both sWGS and targeted next-generation sequencing. Results showed highly similar patterns of global copy number change between STIC lesions and invasive carcinoma samples within each patient. Ploidy changes were evident in STIC lesions, but not p53 signatures, and there was a strong correlation between ploidy in STIC lesions and invasive ovarian/fallopian tube and metastatic samples in each patient. The reconstruction of sample phylogeny for each patient from relative copy number indicated that high ploidy, when present, occurred early in the evolution of HGSC, which was further validated by copy number signatures in ovarian and metastatic tumours. These findings suggest that aberrant ploidy, suggestive of WGD, arises early in HGSC and is detected in STIC lesions, implying that the trajectory of HGSC may be determined at the earliest stages of tumour development. © 2024 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Abstract LB311: Multimodal spatial profiling reveals the emergence of an immune suppressive microenvironment at the initial stages of high-grade serous ovarian cancer development

Abstract Introduction: Despite the clear genetic evidence linking serous tubal intraepithelial carcinoma (STIC) and high-grade serous ovarian carcinoma (HGSOC), the specific conditions and events that promote the progression of STIC lesions into invasive disease remain poorly understood. Method: As a critical initial step, we have assembled a cohort of incidental p53 signatures, STIC lesions, and STIC with concurrent HGSOC. We have performed extensive multi-modal analysis using multiplexed tissue imaging and spatial transcriptomics that identify features of the immune system that play a vital role in the early steps of HGSOC development. We have processed 43 specimens using highly multiplexed tissue imaging at single-cell resolution (cyclic immunofluorescence, CyCIF), and 35 specimens for micro-regional spatial transcriptomics using the GeoMx (Whole Transcriptome, Nanostring) on over 450 pathologist-annotated regions of interest. Results: Our data suggests an immune-cold environment and T-cell dysfunction in STIC lesions, including incidental STIC. One of the significant immune populations identified was CD103+ tissue-resident memory T cells (TRM). In incidental p53 signatures, activation of TRM was rare, similar to FT, which may indicate the absence of sensing “tumor antigen” by these TRM. CyCIF analysis also revealed that most incidental STIC lesions (7/9 cases) overexpress major histocompatibility complex (MHC) class I compared to the normal epithelium, especially both HLA complex, HLA-A and HLA-E. Most STICs showed extensive intra-lesion heterogeneity, with some STICs remaining HLA-A and HLA-E negative. Incidental p53 signatures, on the other hand, were mostly HLA-A and HLA-E negative and, when positive, had only a few cells expressing HLA. We hypothesized that there might be a natural selection of HLA-E-positive clones as STICs progress to HGSOC. Consistent with this, HGSOC showed further overexpression of HLA-E. However, HLA-E heterogeneity was still observed in the invasive tumor, with both positive and negative clones co-existing. Geomx data suggested that the interferon signaling pathway is upregulated in the epithelial of HLA-E positive STIC and cancer clones compared to HLA-E negative clones. In turn, both HLA-A and HLA-E might be overexpressed in the epithelial of HLA-E-positive STICs. Overall, we showed that the response in interferon (IFN) α and γ, NF-KB, and IL-6-induced STAT-3 pathways were upregulated in both STIC lesions and carcinoma. The role of these pathways, especially STAT-3 pathway, has been shown in other aneuploid cancers in promoting immune escape, cell proliferation and migration, chemoresistance and inhibiting apoptosis. We have shown the co-localization of cGAS and BAF, a marker for micronuclei rupture, by super-resolution 3D imaging to confirm one of the mechanisms of IFN activation. Conclusion: Taken together, these data may indicate chromosomal instability is one of the mechanisms that is driving the IFN-signaling pathway and, hence, a potential selective advantage for HLA-E-positive clones in tumorigenesis, leading to inhibiting NK cell surveillance followed by reducing T cell infiltration. Citation Format: Tanjina Kader, Jia-Ren Lin, Shannon Coy, Clemens Hug, Yu-An Chen, Roxanne J. Pelletier, Mariana Leon, John Lee, Yi-Lin Xu, Clarence Yapp, Natalie Shih, Gabriel Mingo, Euihye Jung, Srishti Rathore, Judith Agudo, Charles Drescher, Peter K. Sorger, Ronny Drapkin, Sandro Santagata. Multimodal spatial profiling reveals the emergence of an immune suppressive microenvironment at the initial stages of high-grade serous ovarian cancer development [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB311.

High-grade serous ovarian cancer (HGSOC) with fallopian tube involvement.

Literature data present new studies about precancerous lesions of pelvic serous carcinoma that originate from the tubal secretory cells. It has long been thought that ovarian cancer cannot be prevented by prophylactic screening or surgery. In recent years, gynecologists have adapted to new principles and so, during routine hysterectomies in perimenopausal women for benign uterine pathologies, salpingo-oophorectomy is performed as a prophylactic approach. The purpose of our article was to draw attention to the association between abnormal fallopian tube pathology and the presence of serous ovarian neoplasia in perimenopausal women at risk. We report the case of a 45-year-old woman who had unspecific symptoms of abdominal pain and loss of appetite and weight. A pelvic magnetic resonance imaging was performed, and an ovarian mass was detected. Our case shows that the fallopian tube can be the primary point of origin for a pelvic disease, therefore prevention is possible with early computed tomography scan and annual ultrasound. The patient presented with a T1c staging post-surgery and her chances of survival could have decreased if she had postponed medical examination longer. We found a significant increase in the absolute number of tubal secretory cells in patients with ovarian neoplasia, which supports the assumption that serous tubal intraepithelial carcinoma lesions are found especially in the serous ovarian type. Our article is a strong suggestion that serous ovarian cancer originates from the fallopian tube and can potentially serve as a sensitive biomarker for early serous carcinogenesis within the fallopian tube.

Volumetric sonographic depiction of the fallopian tube lumen for the early detection of tubal abnormalities: A work in progress

ObjectivesThe fallopian tube (FT) has emerged as an important imaging target in the detection of early ovarian cancer, which has remained an evasive challenge in the field of medicine. Recent understanding of ovarian cancer has identified the distal FT as the site of early tumorigenesis. Evaluation of the FT poses challenges due to the small size and variable anatomic position. This study outlines image acquisition and analysis techniques for volumetric depiction of the FT lumen. MethodsWomen with BRCA+ ​mutations undergoing risk reduction salpingo-ophorectomy were imaged using contrast-enhanced 3D transvaginal ultrasound (n ​= ​7). Sono-salpingography was conducted with intraluminal contrast instilled through the cervix for improved imaging of the FT lumen. Three-dimensional volumetric data was collected for qualitative and quantitative image analysis. Pathologic correlation was conducted using the Sectioning and Extensively Examining the Fimbriated End Protocol (SEE-FIM). ResultsStudy subjects underwent 3D imaging with trans-cervical FT lumen contrast enhancement at the time of our interim reporting. None of the subjects in our initial study had serous tubal intraepithelial carcinoma (STIC) lesions, however one had acute inflammation of the FT. The 3D quantitative image analysis demonstrated areas of luminal irregularity corresponding to the regions of inflammation on pathology. ConclusionsOur study shows promise in the detailed evaluation of the FT lumen for the detection of luminal abnormalities. We continue to optimize image acquisition and analysis techniques for the detection of STIC lesions as we enroll additional patients.

Serous tubal intraepithelial carcinoma detected during benign gynecologic surgery: a case report

High-grade serous carcinoma (HGSC) is the most common type of pelvic cancer among women. Serous tubal intraepithelial carcinoma (STIC) is a precursor lesion of HGSC. Herein, we report a rare occurrence of STIC in patients undergoing surgery for benign indications without a family history of ovarian cancer. A 77-year-old woman underwent total laparoscopic hysterectomy and bilateral salpingo-oophorectomy for uterine prolapse. Pathological examination revealed bilateral STIC without ovarian abnormalities, and no other abnormal findings were noted. Another patient, a 49-year-old woman, underwent laparoscopic total hysterectomy and bilateral salpingectomy for uterine fibroids. STIC lesions were observed in both fallopian tubes. Subsequently, a staging was performed. No additional lesions were found, and the patient was followedup through imaging and blood tests. As reports of STIC lesions are rare, data on their clinical outcomes and management strategies are limited. In this report, we present cases of incidental STIC in benign surgery and discuss its proper interpretation and management. Through the early detection of STIC lesions, patients with risk factors can be identified in advance, which will allow prevention and early detection of ovarian cancer. Opportunistic salpingectomy was also actively discussed in this regard.

A questionnaire-based survey on the diagnostic and therapeutic approaches for patients with STIC in Germany

PurposeDespite the growing understanding of the carcinogenesis of pelvic high-grade serous carcinoma (HGSC) of the ovary and peritoneum and its precursor lesion serous tubal intraepithelial carcinoma (STIC), evidence-based proven recommendations on the clinical management of patients with STIC are lacking so far.MethodsA questionnaire containing 21 questions was developed to explore the clinical experience with patients with the diagnosis of STICs and the diagnostic, surgical and histopathological approaches in Germany. Overall, 540 clinical heads of department in all German gynaecological centres were asked to participate.Results131 questionnaires (response rate 24.3%) were included in this survey. 45.8% of the respondents had treated one to three STIC patients during their career. 75.6% of the respondents performed opportunistic bilateral salpingectomies during other gynaecological surgeries. Most of the participants (31.3%) started with the SEE-FIM (Sectioning and Extensively Examining the FIMbria) protocol in 2014. It was requested by 39.7% centres for prophylactic salpingectomies, by 13.7% for both prophylactic and opportunistic salpingectomies and by 22.1% for neither of both. 38.2%, 1.5% and 24.4% of the participants would use the laparoscopic, transverse and midline laparotomic approach for a surgical staging procedure, respectively. 25.6% (54.7%) of the respondents recommended a hysterectomy in premenopausal (versus postmenopausal) patients with a STIC, 24.4% (88.4%) a bilateral oophorectomy and 50.0% (4.7%) an affected side oophorectomy (all p values < 0.001). Omentectomy, pelvic and para-aortic lymphadenectomy would be performed by 60.5% (64.0%), 9.3% (11.6%) and 9.3% (11.6%) of respondents in premenopausal (versus postmenopausal) patients (all p values > 0.05).ConclusionOur survey highlights significant inconsistency in the management of patients with STIC. Prospective data are urgently needed to elucidate the clinical impact of a STIC lesion and its clinical management.

L1CAM is required for early dissemination of fallopian tube carcinoma precursors to the ovary

Most ovarian high-grade serous carcinomas (HGSC) arise from Serous Tubal Intraepithelial Carcinoma (STIC) lesions in the distal end of the fallopian tube (FT). Formation of STIC lesions from FT secretory cells leads to seeding of the ovarian surface, with rapid tumor dissemination to other abdominal structures thereafter. It remains unclear how nascent malignant cells leave the FT to colonize the ovary. This report provides evidence that the L1 cell adhesion molecule (L1CAM) contributes to the ability of transformed FT secretory cells (FTSEC) to detach from the tube, survive under anchorage-independent conditions, and seed the ovarian surface. L1CAM was highly expressed on the apical cells of STIC lesions and contributed to ovarian colonization by upregulating integrins and fibronectin in malignant cells and activating the AKT and ERK pathways. These changes increased cell survival under ultra-low attachment conditions that mimic transit from the FT to the ovary. To study dissemination to the ovary, we developed a tumor-ovary co-culture model. We showed that L1CAM expression was important for FT cells to invade the ovary as a cohesive group. Our results indicate that in the early stages of HGSC development, transformed FTSECs disseminate from the FT to the ovary in a L1CAM-dependent manner.

Clinical and genetic findings of incidental serous tubal intraepithelial carcinoma (145)

<b>Objectives:</b> Serous tubal intraepithelial carcinoma (STIC) is thought to represent the precursor lesion to the high-grade serous fallopian tube or ovarian carcinoma. STIC lesions are found 0.6-6% of the time in women undergoing risk-reducing salpingo-oophorectomy (RRSO) in the setting of a known hereditary predisposition. = However, due to the rarity of incidentally identified STIC lesions, there is limited data to guide management. NCCN guidelines suggest consideration of surgical staging and referral for genetic evaluation. In the absence of a known pathogenic variant as the indication for surgery, there is no data on rates of genetic testing or long-term outcomes. The objective of this study was to describe both clinical outcomes as well as genetic information collected for patients with incidentally noted STIC lesions. <b>Methods:</b> Following IRB approval, pathology records were used to identify all patients diagnosed with a STIC lesion on final pathology from 2007-2021 at a single institution. STIC lesions were characterized utilizing immunohistochemistry. Only patients with STIC lesions undergoing surgery for benign indications were included. Demographic, clinical-pathologic, and genetic data were collected. <b>Results:</b> A total of 16 patients were identified. The median age at diagnosis was 65.5 years (39-80). Fifteen patients (93.8%) had unilateral STIC lesions with one patient having bilateral STIC lesions. Most lesions were positive for p53 (94.1%) and had increased Ki67 proliferation, defined as >10% (94.1%). Two patients (12.5%) had a personal history of malignancy prior to their STIC lesion diagnosis. Patients had a wide variety of presentations, including pelvic mass (37.5%), prolapse (31.3%), abnormal uterine bleeding (25%), and pelvic pain (6.3%). Nine patients had additional surgical procedures performed (56.3%), and no cancer diagnosis was identified for any patient. Additional procedures included contralateral salpingo-oophorectomy, omentectomy, pelvic and paraaortic lymph node dissection, and peritoneal biopsies. No patients received adjuvant treatment. Eleven patients were offered a genetic counseling referral (68.8%), with seven patients completing a counseling appointment (63.6%). Five of the seven patients who completed their visit met criteria for testing based on additional personal and/or family history (71.4%), with one patient testing positive for a PALB2 pathogenic variant (20% of tested patients). Three patients, none of whom underwent genetic testing, were subsequently diagnosed with breast cancer during the follow-up period. <b>Conclusions:</b> Incidental STIC lesions are rare. In this cohort, there were no ovarian, fallopian tube, or primary peritoneal cancer diagnoses after additional surgical staging or during follow-up. More data is needed to guide treatment recommendations. However, compared to STIC lesions in patients undergoing RRSO for a known predisposition, it is not clear whether additional surgical procedures are warranted in patients with incidentally noted STIC lesions. Our data support NCCN recommendations for referral for genetic evaluation as 71% qualified for testing. One patient (20% of those who qualified for testing) had a clinically actionable pathogenic variant. Notably, three patients later developed breast cancer; however, without genetic testing, we cannot determine if there may be a genetic link. Further studies of these lesions are warranted.

Focal Serous Tubal Intra-Epithelial Carcinoma Lesions Are Associated With Global Changes in the Fallopian Tube Epithelia and Stroma.

ObjectiveSerous tubal intra-epithelial carcinoma (STIC) lesions are thought to be precursors to high-grade serous ovarian cancer (HGSOC), but HGSOC is not always accompanied by STIC. Our study was designed to determine if there are global visual and subvisual microenvironmental differences between fallopian tubes with and without STIC lesions.MethodsComputational image analyses were used to identify potential morphometric and topologic differences in stromal and epithelial cells in samples from three age-matched groups of fallopian tubes. The Benign group comprised normal fallopian tubes from women with benign conditions while the STIC and NoSTIC groups consisted of fallopian tubes from women with HGSOC, with and without STIC lesions, respectively. For the morphometric feature extraction and analysis of the stromal architecture, the image tiles in the STIC group were further divided into the stroma away from the STIC (AwaySTIC) and the stroma near the STIC (NearSTIC). QuPath software was used to identify and quantitate secretory and ciliated epithelial cells. A secretory cell expansion (SCE) or a ciliated cell expansion (CCE) was defined as a monolayered contiguous run of >10 secretory or ciliated cells uninterrupted by the other cell type.ResultsImage analyses of the tubal stroma revealed gradual architectural differences from the Benign to NoSTIC to AwaySTIC to NearSTIC groups. In the epithelial topology analysis, the relative number of SCE and the average number of cells within SCE were higher in the STIC group than in the Benign and NoSTIC groups. In addition, aging was associated with an increased relative number of SCE and a decreased relative number of CCE. ROC analysis determined that an average of 15 cells within SCE was the optimal cutoff value indicating the presence of a STIC lesion in the tubal epithelium.ConclusionsOur findings suggest that global stromal alterations and age-associated reorganization of tubal secretory and ciliated cells are associated with STIC lesions. Further studies will need to determine if these alterations precede STIC lesions and provide permissible conditions for the formation of STIC.

TP53 variants in p53 signatures and the clonality of STICs in RRSO samples.

ObjectivePrecursor lesions may be identified in fallopian tube tissue after risk-reducing salpingo-oophorectomy (RRSO) in patients with pathogenic variants of BRCA1/2. Serous tubal intraepithelial carcinoma (STIC) is considered a precursor of high-grade serous carcinoma, whereas the significance of the p53 signature remains unclear. In this study, we investigated the relationship between the p53 signature and the risk of ovarian cancer.MethodsWe analyzed the clinicopathological findings and conducted DNA sequencing for TP53 variants of p53 signatures and STIC lesions isolated using laser capture microdissection in 13 patients with pathogenic variants of BRCA1/2 who underwent RRSO and 17 control patients with the benign gynecologic disease.Results TP53 pathogenic variants were detected significantly higher in RRSO group than control (p<0.001). No difference in the frequency of p53 signatures were observed between groups (53.8% vs 29.4%; p=0.17). TP53 sequencing and next-generation sequencing analysis in a patient with STIC and occult cancer revealed 2 TP53 mutations causing different p53 staining for STICs and another TP53 mutation shared between STIC and occult cancer.ConclusionThe sequence analysis for TP53 revealed 2 types of p53 signatures, one with a risk of progression to STIC and ovarian cancer with pathological variants in TP53 and the other with a low risk of progression without pathological variants in TP53 as seen in control.

TGFBI Production by Macrophages Contributes to an Immunosuppressive Microenvironment in Ovarian Cancer.

The tumor microenvironment evolves during malignant progression, with major changes in nonmalignant cells, cytokine networks, and the extracellular matrix (ECM). In this study, we aimed to understand how the ECM changes during neoplastic transformation of serous tubal intraepithelial carcinoma lesions (STIC) into high-grade serous ovarian cancers (HGSOC). Analysis of the mechanical properties of human fallopian tubes (FT) and ovaries revealed that normal FT and fimbria had a lower tissue modulus, a measure of stiffness, than normal or diseased ovaries. Proteomic analysis of the matrisome fraction between FT, fimbria, and ovaries showed significant differences in the ECM protein TGF beta induced (TGFBI, also known as βig-h3). STIC lesions in the fimbria expressed high levels of TGFBI, which was predominantly produced by CD163-positive macrophages proximal to STIC epithelial cells. In vitro stimulation of macrophages with TGFβ and IL4 induced secretion of TGFBI, whereas IFNγ/LPS downregulated macrophage TGFBI expression. Immortalized FT secretory epithelial cells carrying clinically relevant TP53 mutations stimulated macrophages to secrete TGFBI and upregulated integrin αvβ3, a putative TGFBI receptor. Transcriptomic HGSOC datasets showed a significant correlation between TGFBI expression and alternatively activated macrophage signatures. Fibroblasts in HGSOC metastases expressed TGFBI and stimulated macrophage TGFBI production in vitro. Treatment of orthotopic mouse HGSOC tumors with an anti-TGFBI antibody reduced peritoneal tumor size, increased tumor monocytes, and activated β3-expressing unconventional T cells. In conclusion, TGFBI may favor an immunosuppressive microenvironment in STICs that persists in advanced HGSOC. Furthermore, TGFBI may be an effector of the tumor-promoting actions of TGFβ and a potential therapeutic target. SIGNIFICANCE: Analysis of ECM changes during neoplastic transformation reveals a role for TGFBI secreted by macrophages in immunosuppression in early ovarian cancer.

Exploring the clinical significance of serous tubal intraepithelial carcinoma associated with advanced high-grade serous ovarian cancer: A Memorial Sloan Kettering Team Ovary Study

ObjectiveTo evaluate the clinical significance and genomic associations of concurrent serous tubal intraepithelial carcinoma (STIC) with high-grade serous carcinoma (HGSC) of the ovary in women undergoing primary debulking surgery (PDS). MethodsAll patients who underwent PDS for HGSC between 01/2015 and 12/2018 were captured in a prospectively maintained institutional database. Patients were categorized based on the presence or absence of concurrent STIC noted on final pathology. Demographic, perioperative, and outcomes data were collected, and groups were compared using standard statistical tests. Progression-free survival (PFS) and overall survival (OS) were evaluated using the Kaplan-Meier method. For comparison of differences in somatic alterations between the two cohorts, specimens were sequenced using MSK-IMPACT. ResultsOf 306 eligible patients, 87 (28%) had a concurrent STIC lesion (+STIC) and 219 (72%) did not (no-STIC). Demographics and clinicopathological factors were similar between the two cohorts, except for a significantly higher median preoperative CA-125 level in the no-STIC group (423 U/mL vs. 321 U/mL; p=0.029). There were no significant differences in median PFS (22.7 months [95%CI: 18.9-28.4] vs. 27.7 months [95%CI: 25.5-30.5]; p=0.126) and 3- year OS rate (81% [95%CI: 70-88%] vs. 85% [95%CI: 78-90%]; p=0.392) between +STIC and no-STIC patients, respectively. Targeted DNA-sequencing via MSK-IMPACT showed a similar distribution of driver mutations or structural genetic alterations, and affected genetic signaling pathways were similar between the cohorts. ConclusionsThere were no identifiable clinical and genetic differences in patients with HGSC and concurrent STIC. These data suggest a comparable, if not identical, disease process.

Abstract B11: Collective extrusion initiates dissemination in organotypic model of high-grade serous carcinoma

Abstract Development of serous tubal intraepithelial carcinoma (STIC) from transformed fallopian tube secretory epithelial cells (FTSEC) is considered to be an initiating event for a significant proportion of high-grade serous carcinomas (HGSCs). Some regions of STIC lesions can form multicellular loosely cohesive outgrowths that apically extend out of the tubal epithelium. These outgrowths can detach and disseminate within the peritoneal cavity, causing organ obstruction. Immunohistochemical analysis of STICs suggests the possibility that molecular pathways associated with proliferation, DNA repair, cytoskeletal dynamics, and extracellular matrix adhesion contribute to outgrowth formation. Due to limited availability of transformed FTSEC in vitro culture models that faithfully capture outgrowth dynamics, the role of these pathways in STIC/HGSC outgrowth formation remains unknown. Here we present the development of an organotypic model of outgrowth formation. Long-term live-cell imaging of transformed human, and mouse FTSEC and STIC-like multicellular organotypic assemblies, have shown that outgrowths are initiated by collective apical extrusion of less-cohesive, loosely attached cell populations that can proliferate outside of the organotypic assembly. mRNA and immunofluorescence analysis of loosely attached cell populations revealed: (i) activation of Rho pathway, (ii) increased expression of several alpha integrin subunits that form heterodimers with beta 1 integrin, and (iii) nonpolarized apical and junctional localization of activated integrin beta 1. Pharmacologic or genetic inhibition of Rho-associated kinase (ROCK) blocked outgrowth formation without affecting cell proliferation. Conversely, activation of Rho significantly accelerated outgrowths, indicating that Rho-ROCK is a critical regulator of early steps of HGSC dissemination. Quantitative image-based evaluation of ROCK target phosphorylated myosin light chain expression in patient-derived xenograft cells revealed the presence of cell populations with high ROCK activation. Blocking integrin beta 1 activity resulted in the disintegration of already formed outgrowths. Our data indicate that cell populations with high Rho/ROCK activity remodel integrin beta 1-dependent adhesion to initiate apical extrusion and peritoneal dissemination. Citation Format: Sarah Alshehri, Sadaf Farsinejad, Douglas Kung, Estefan Santi, Yali Zhai, Thomas Cattabiani, Hongjun Wang, Kathleen Cho, Marcin Iwanicki. Collective extrusion initiates dissemination in organotypic model of high-grade serous carcinoma [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research; 2019 Sep 13-16, 2019; Atlanta, GA. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(13_Suppl):Abstract nr B11.

Novel protein and immune response markers of human serous tubal intraepithelial carcinoma of the ovary.

Ovarian cancer is the leading cause of death among gynecologic diseases in the USA and Europe. High-grade serous carcinoma (HGSC) of the ovary, the most aggressive type of ovarian cancer, is typically diagnosed at advanced stages when the 5-year survival is dismal. Since the cure rate for stage I HGSC is high, early detection of localized initial disease may improve patient outcomes. Serous tubal intraepithelial carcinoma (STIC) is considered to be a precursor lesion of HGSC. Discovery of biomarkers associated with STIC could aid in the development of an HGSC screening algorithm. Using immunohistochemical staining, we have demonstrated overexpression of UCHL1, ADAMTS13, and GAPDH in patients' STIC lesions, but not in cancer-free fallopian tubes. We additionally demonstrated a marked increase of T cells in perineoplastic stroma surrounding STIC lesions (largely CD4 + cells), but not in normal fallopian tubes and HGSC. FOXP3 + T regulatory cells are absent in STIC lesions but are present in HGSC. These observations indicate the microenvironment surrounding a STIC lesion may be immune promoting in contrast to the immune suppressive microenvironment of invasive carcinoma. In summary, we have identified UCHL1, ADAMTS13, and GAPDH as novel potentially useful markers associated with early stages of HGSC tumorigenesis and possibly contribute to STIC immunogenicity. The lack of immune suppression in the STIC microenvironment indicates that the immune system can still recognize and keep STIC controlled at this stage of the tumor development.

Abstract AP07: PROTEIN AND IMAGING MARKERS FOR EARLY DETECTION OF EPITHELIAL OVARIAN CANCER

Abstract A central problem in ovarian cancer is late diagnosis, where the 5-year survival rate plummets well below 50%. It is now believed that a significant fraction of ovarian high grade serous carcinoma (HGSC) may actually start in the fallopian tubes (FTs), and that precancerous changes are detectable before metastasis to the ovary and peritoneal cavity occurs. A recently published molecular evolutionary analysis identifies a window of 7 years between development of a serous tubal intraepithelial carcinoma (STIC) and initiation of ovarian carcinoma, with metastases following rapidly thereafter. The authors are working to address the unmet clinical need for a minimally invasive test for early (pre-metastatic) ovarian cancer. Existing whole-body imaging techniques and transvaginal ultrasound have thus far displayed inadequate resolution and sensitivity, however optical imaging methods could fulfill the criteria for detection of primary HGSC when it is still located in the FTs and before it has spread to the ovaries. We have shown that two optical imaging modalities, optical coherence tomography (OCT) and multispectral fluorescence imaging (MFI) have great promise for detection of ovarian and FT abnormalities. In a small ex-vivo study, we found that 5 MFI measurements were sufficient to distinguish between normal, cancerous, and benign FT and ovary tissue with 100% sensitivity and specificity. We used laparoscopic OCT in an in-vivo study of 17 women and revealed distinct image features for normal, cancerous, and benign abnormalities of the ovary. For minimally invasive imaging of the fallopian tubes, a sub-millimeter diameter, flexible, steerable endoscope is necessary in order to navigate through the natural orifice of the ostium in the uterus. We have recently prototyped the smallest (0.8 mm diameter) OCT/MFI imaging endoscope with a forward-viewing imaging channel. The system as tested has approximately 70 degree full field of view, a working distance from 1 mm to infinity, and resolution that varies from 35 µm at 1 mm to 180 µm at 10 mm working distance. Such an imaging test is minimally invasive however not appropriate for wholesale screening of the general population. Therefore, we propose to utilize it as an adjunct confirmatory test after an initial positive or suspicious blood test. Our preliminary data indicate that there are significant changes in serum protein biomarkers in HGSC cases more than 18 months before diagnosis. We have identified FBG and PF4 as pre-diagnostic biomarkers of HGSC with 18-84 months lead time, and have generated and validated a 3-biomarker panel (FBG, PF4, and CA125) that classifies HGSC with &amp;gt;80% sensitivity/&amp;gt;70% specificity and 18-84 months lead time. We have identified overexpression of several glycolytic enzymes in STIC lesions and in human pre-diagnostic serum samples, indicating potential usefulness of these proteins as screening biomarkers and potential utility of glycolysis as imaging biomarker of STIC lesion. Our continuing work is focused on refining the serum protein biomarker sensitivity and specificity, creating a second-generation falloposcope for a first-in-women feasibility study, and creating an integrated model that incorporates both sets of data into an early EOC detection method. Citation Format: Jennifer K. Barton, Anna E. Lokshin, David A. Fishman, John F. Black. PROTEIN AND IMAGING MARKERS FOR EARLY DETECTION OF EPITHELIAL OVARIAN CANCER [abstract]. In: Proceedings of the 12th Biennial Ovarian Cancer Research Symposium; Sep 13-15, 2018; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2019;25(22 Suppl):Abstract nr AP07.

Defining the molecular evolution of extrauterine high grade serous carcinoma

ObjectiveHigh grade serous carcinoma (HGSC) is the most common and most aggressive, subtype of epithelial ovarian cancer. It presents as advanced stage disease with poor prognosis. Recent pathological evidence strongly suggests HGSC arises from the fallopian tube via the precursor lesion; serous tubal intraepithelial carcinoma (STIC). However, further definition of the molecular evolution of HGSC has major implications for both clinical management and research. This study aims to more clearly define the molecular pathogenesis of HGSC. MethodsSix cases of HGSC were identified at the Northern Ireland Gynaecological Cancer Centre (NIGCC) that each contained ovarian HGSC (HGSC), omental HGSC (OMT), STIC, normal fallopian tube epithelium (FTE) and normal ovarian surface epithelium (OSE). The relevant formalin-fixed paraffin embedded (FFPE) tissue samples were retrieved from the pathology archive via the Northern Ireland Biobank following attaining ethical approval (NIB11:005).Full microarray-based gene expression profiling was performed on the cohort. The resulting data was analysed bioinformatically and the results were validated in a HGSC-specific in-vitro model. ResultsThe carcinogenesis of HGSC was investigated and showed the molecular profile of HGSC to be more closely related to normal FTE than OSE. STIC lesions also clustered closely with HGSC, indicating a common molecular origin. ConclusionThis study provides strong evidence suggesting that extrauterine HGSC arises from the fimbria of the distal fallopian tube. Furthermore, several potential pathways were identified which could be targeted by novel therapies for HGSC. These findings have significant translational relevance for both primary prevention and clinical management of the disease.

Evidence of a Monoclonal Origin for Bilateral Serous Tubal Intraepithelial Neoplasia.

Serous tubal intraepithelial carcinoma (STIC) is found in 10% to 60% of cases of tuboovarian high-grade serous carcinoma (HGSC) and is presumed to be the site of origin, linking many HGSCs to the fallopian tube. Bilateral STIC is present in ∼20% of cases. Because clonal Tp53 mutations are a defining feature of HGSC, including their associated STICs, we analyzed 4 cases of bilateral serous tubal intraepithelial neoplasia (STIN), including STIC and Tp53-mutated serous tubal intraepithelial lesions (STILs), associated with HGSC to determine whether they contained the same or different p53 mutations. Extracted DNA from STINs, concurrent HGSCs and control tissues was analyzed for mutations in all exons of Tp53. Sequencing was successful in 3 of the 4 cases, and an identical Tp53 mutation was detected in the HGSC and bilateral STINs in 2 of these 3 cases. One STIN was morphologically a STIL. These findings confirm that a subset of bilateral STINs share the same Tp53 mutation, implying that at least one of the STINs is an intraepithelial metastasis from either the contralateral STIN or HGSC. This study complements others addressing the multiple origins of STIN in the setting of existing HGSC. It further underscores the fact that potential overlap in biologic behavior between STILs and STICs as well as timing and direction of metastatic spread has yet to be resolved.

Development of Peritoneal Carcinoma in women diagnosed with Serous Tubal Intraepithelial Carcinoma (STIC) following Risk-Reducing Salpingo-Oophorectomy (RRSO)

IntroductionThe management of Serous Tubal Intraepithelial Carcinoma (STIC) found at the time of Risk-Reducing Salpingo-Oophorectomy (RRSO) remains unclear. We set out to analyse the incidence of peritoneal carcinomas developed after prophylactic surgery and to formulate further guidance for these patients.MethodsThis is a retrospective study of 300 consecutive RRSO performed at the Royal Marsden Hospital between January 2008 and January 2017.ResultsThe median age at RRSO was 47.8 years (range 34 to 60 years) and median BMI was 26.2 kg/m2 (range 16 to 51 kg/m2). A total of 273 patients (91%) were tested for BRCA mutations. Of these, 124 (45.4%) had a BRCA 1 mutation, 118 (43.2%) had a BRCA 2 mutation, 2 (0.7%) had both a BRCA 1 and a BRCA 2 mutation and 29 (10.6%) had no BRCA mutation detected. Isolated STIC lesions were identified in 7 cases (2.3%) and p53 signatures in 75 cases (25%). There were five (1.6%) incidental tubal carcinomas and one (0.3%) ovarian carcinoma at the time of surgery. Two (28.6%) of the 7 patients with STIC identified following RRSO had high grade serous peritoneal carcinoma diagnosed at 53 and 75 months. One (0.3%) patient from the other 287 patients from our series with no STIC diagnosis or incidental carcinomas at RRSO developed high grade serous carcinoma of peritoneal origin after 92 months.ConclusionThis study demonstrates that when a STIC lesion is identified following RRSO there is a significantly higher risk of a subsequent peritoneal cancer. Although there is no published consensus in literature, we recommend that consideration should be given for long term follow-up if a STIC lesion is identified at RRSO.

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 © 2019 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Methylomic Analysis of Ovarian Cancers Identifies Tumor-Specific Alterations Readily Detectable in Early Precursor Lesions.

High-grade serous ovarian carcinoma (HGSOC) typically remains undiagnosed until advanced stages when peritoneal dissemination has already occurred. Here, we sought to identify HGSOC-specific alterations in DNA methylation and assess their potential to provide sensitive and specific detection of HGSOC at its earliest stages. MethylationEPIC genome-wide methylation analysis was performed on a discovery cohort comprising 23 HGSOC, 37 non-HGSOC malignant, and 36 histologically unremarkable gynecologic tissue samples. The resulting data were processed using selective bioinformatic criteria to identify regions of high-confidence HGSOC-specific differential methylation. Quantitative methylation-specific real-time PCR (qMSP) assays were then developed for 8 of the top-performing regions and analytically validated in a cohort of 90 tissue samples. Lastly, qMSP assays were used to assess and compare methylation in 30 laser-capture microdissected (LCM) fallopian tube epithelia samples obtained from cancer-free and serous tubal intraepithelial carcinoma (STIC) positive women. Bioinformatic selection identified 91 regions of robust, HGSOC-specific hypermethylation, 23 of which exhibited an area under the receiver-operator curve (AUC) value ≥ 0.9 in the discovery cohort. Seven of 8 top-performing regions demonstrated AUC values between 0.838 and 0.968 when analytically validated by qMSP in a 90-patient cohort. A panel of the 3 top-performing genes (c17orf64, IRX2, and TUBB6) was able to perfectly discriminate HGSOC (AUC 1.0). Hypermethylation within these loci was found exclusively in LCM fallopian tube epithelia from women with STIC lesions, but not in cancer-free fallopian tubes. A panel of methylation biomarkers can be used to accurately identify HGSOC, even at precursor stages of the disease.