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ObjectivesWhile ovarian cancer is the third most common Lynch syndrome-associated cancer in women, there is no established screening strategy to identify Lynch syndrome in this population. The objective of this study was to assess whether the 4-item brief Family History Questionnaire can be used as a screening tool to identify women with ovarian cancer at risk of Lynch syndrome.MethodsIn this prospective cohort study, participants with newly diagnosed non-serous, non-mucinous ovarian cancer completed the brief Family History Questionnaire, extended Family History Questionnaire, and had tumors assessed with immunohistochemistry for mismatch repair proteins, MLH1 methylation, and microsatellite instability testing. All underwent universal germline testing for Lynch syndrome. Performance characteristics were compared between the brief Family History Questionnaire, extended Family History Questionnaire, immunohistochemistry±MLH1 methylation, and microsatellite instability testing.ResultsOf 215 participants, 169 (79%) were evaluable with both the brief Family History Questionnaire and germline mutation status; 12 of these 169 were confirmed to have Lynch syndrome (7%). 10 of 12 patients (83%) with Lynch syndrome were correctly identified by the brief Family History Questionnaire, compared with 6 of 11 (55%) by the extended Family History Questionnaire, 11 of 13 (85%) by immunohistochemistry±MLH1 methylation, and 9 of 11 (82%) by microsatellite instability testing. The sensitivity, specificity, positive predictive values, and negative predictive values of the brief Family History Questionnaire were 83%, 65%, 15%, and 98%, respectively. A combined approach with immunohistochemistry and the brief Family History Questionnaire correctly identified all 12 patients with Lynch syndrome. The brief Family History Questionnaire was more sensitive than the extended Family History Questionnaire and took ConclusionsThe brief Family History Questionnaire alone or combined with immunohistochemistry may serve as an adequate screening strategy, especially in centers without access to universal tumor testing.

The lesbian, gay, bisexual, transgender, queer/questioning and two-spirited, plus (LGBTQ2 +) community experiences cancer-related health disparities and inequities. Our objective was to assess LGBTQ2 + knowledge, attitudes, practices and education interest of healthcare professionals (HCPs), identify opportunities to improve care and inform the development of an HCP education curriculum. This was a mixed methods quality improvement study conducted within a tertiary academic cancer centre. An email was sent to all gynaecologic oncology disease site staff (n = 92) with a secure link to an online survey. We measured respondents' sociodemographic characteristics and LGBTQ2 + knowledge, attitudes, practice behaviours and education interest. Open comments explored HCP experiences and reservations caring for LGBTQ2 + patients and suggestions to improve care. Seventy-five out of ninety-two (82%) HCPs completed the survey, with 7% identifying as LGBTQ2 + . HCPs reported feeling less comfortable (88% vs. 80%, p = 0.031) and knowledgeable (44% vs. 27%, p 0.001) caring for transgender patients compared to LGBQ2 + patients. Most (76%) were unaware whether LGBTQ2 + -specific patient educational materials existed within their institution. Almost all (92% strongly agreed/agreed) were interested in receiving LGBTQ2 + -specific education. Two themes emerged from analysis of open comments: (i) HCPs are concerned of offending LGBTQ2 + individuals because of their lack of knowledge and (ii) HCPs desire LGBTQ2 + -specific health training, specifically in asking pronouns and caring for transgender patients. HCPs report competency gaps in caring for LGBTQ2 + patients with cancer but desire education. In response, we recommend institutions develop an educational curriculum for HCPs improve communication and inclusivity in cancer care.

Findings on impact of mismatch repair deficiency (MMRd) on patient outcomes in endometrial cancer (EC) have been inconsistent to date. The objective of this study was to compare the oncologic outcomes and recurrence patterns between MMRd and MMR-intact (MMRi) endometrioid EC (EEC).Between 2015 and 2018, we prospectively recruited 492 EEC cases from three cancer centers in Ontario, Canada. Tumors were reflexively assessed for MMR protein expression by immunohistochemistry (IHC). Clinicopathological, survival and recurrence patterns were compared between MMRd and MMRi cases.Of 492 EEC, 348 were MMRi (71%) and 144 were MMRd (29%) with median follow-up of 16.8 months (0-69.6). MMRd tumors tended to be grade 2 or 3 (56% vs. 29%, p 0.001), with propensity for lymphovascular space invasion (28% vs. 18%, p = 0.024), lymph node involvement (7% vs. 5%, p 0.001) and received more adjuvant treatment (46% vs. 33%, p = 0.027). This group also had significantly lower 3-year recurrence-free survival (78% vs. 90%, p = 0.014) although there was no difference in OS (p = 0.603). MMRd cases were more likely to recur in retroperitoneal lymph nodes (p = 0.045). Upon subgroup analysis, MLH1 methylated tumors had the worst prognostic features and survival outcomes.MLH1 methylated EECs exhibit more aggressive features compared to other MMRd and MMRi EECs. This may indicate an inherent difference in tumor biology, suggesting the importance of individualized management based on EC molecular phenotype.

Clinical testing for mismatch repair (MMR) deficiency often entails serial testing of tumor and constitutional DNA using multiple assays. To minimize cost and specimen requirements of MMR testing, we developed an integrated targeted sequencing protocol (termed MultiMMR) that tests for promoter methylation, mutations, copy number alterations, copy neutral loss of heterozygosity, and microsatellite instability from a single aliquot of DNA. Hybrid capture of DNA-sequencing libraries constructed with methylated adapters was performed on 142 samples (60 tumors and 82 constitutional samples) from 82 patients with MMR-associated colorectal, endometrial, and brain cancers as well as a synthetic DNA mix with 11 known mutations. The captured material was split to enable parallel bisulfite and conventional sequence analysis. The panel targeted microsatellite regions and 13 genes associated with MMR, hypermutation, and hereditary colorectal cancer. MultiMMR recapitulated clinical testing results in 23 of 24 cases, was able to explain MMR loss in an additional 29 of 48 patients with incomplete or inconclusive testing, and identified all 11 MMR variants within the synthetic DNA mix. Promoter methylation and microsatellite instability analysis found 95% and 97% concordance with clinical testing, respectively. We report the feasibility for amalgamation of the current stepwise and complex clinical testing workflow into an integrated test for hereditary and somatic causes of MMR deficiency.

ObjectivesFor synchronous endometrial and ovarian cancers, most centers rely on mismatch repair testing of the endometrial cancer to identify Lynch syndrome, and neglect the ovarian tumor site completely. We examined the mismatch repair immunohistochemistry and microsatellite instability results from the endometrium and ovary to assess discordance between the tumor sites and between tests.Methods30 women with newly diagnosed synchronous endometrial and ovarian cancer were prospectively recruited from three cancer centers in Ontario, Canada. Both tumor sites were assessed for mismatch repair deficiency by immunohistochemistry and microsatellite instability test; discordance in results between tumor sites and discordance between test results at each site was examined. Cases with discordant results had tumors sequenced with a targeted panel in order to reconcile the findings. All women underwent mismatch repair gene germline testing.ResultsOf 30 patients, 11 (37%) were mismatch repair deficient or microsatellite instable at either tumor site, with 5 (17%) testing positive for Lynch syndrome. Mismatch repair immunohistochemistry expression was discordant between endometrial and ovarian tumor sites in 2 of 27 patients (7%) while microsatellite instability results were discordant in 2 of 25 patients (8%). Relying on immunohistochemistry or microsatellite instability alone on the endometrial tumor would have missed one and three cases of Lynch syndrome, respectively. One patient with Lynch syndrome with aPMS2pathogenic variant was not detected by either immunohistochemistry or microsatellite instability testing. The rate of discordance between immunohistochemistry and microsatellite instability test was 3.8% in the ovary and 12% in the endometrium.ConclusionsThere was discordance in immunohistochemistry and microsatellite instability results between tumor sites and between tests within each site. Endometrial tumor testing with mismatch repair immunohistochemistry performed well, but missed one case of Lynch syndrome. Given the high incidence of Lynch syndrome (17%), consideration may be given to germline testing in all patients with synchronous endometrial and ovarian cancers.

Background For women with ovarian cancer (OC), the optimal screening strategy to identify Lynch syndrome (LS) has not been determined. In the current study, the authors compared the performance characteristics of various strategies combining mismatch repair (MMR) immunohistochemistry (IHC), microsatellite instability testing (MSI), and family history for the detection of LS. Methods Women with nonserous and/or nonmucinous ovarian cancer were recruited prospectively from 3 cancer centers in Ontario, Canada. All underwent germline testing for LS and completed a family history assessment. Tumors were assessed using MMR IHC and MSI. The sensitivity, specificity, and positive and negative predictive values of screening strategies were compared with the gold standard of a germline result. Results Of 215 women, germline data were available for 189 (88%); 13 women (7%) had pathogenic germline variants with 7 women with mutS homolog 6 (MSH6); 3 women with mutL homolog 1 (MLH1); 2 women with PMS1 homolog 2, mismatch repair system component (PMS2); and 1 woman with mutS homolog 2 (MSH2). A total of 28 women had MMR‐deficient tumors (13%); of these, 11 had pathogenic variants (39%). Sequential IHC (with MLH1 promoter methylation analysis on MLH1‐deficient tumors) followed by MSI for nonmethylated and/or MMR‐intact patients was the most sensitive (92.3%; 95% confidence interval, 64%‐99.8%) and specific (97.7%; 95% confidence interval, 94.2%‐99.4%) approach, missing 1 case of LS. IHC with MLH1 promoter methylation analysis missed 2 patients of LS. Family history was found to have the lowest sensitivity at 55%. Conclusions Sequential IHC (with MLH1 promoter methylation analysis) followed by MSI was found to be most sensitive. However, IHC with MLH1 promoter methylation analysis also performed well and is likely more cost‐effective and efficient in the clinical setting. The pretest probability of LS is high in patients with MMR deficiency and warrants universal screening for LS., Although the incidence of mismatch repair deficiency (MMRd) is low (13%) in patients with nonserous and/or nonmucinous ovarian cancer, the likelihood of having Lynch syndrome is high in patients with MMRd (39%). In the current study, immunohistochemistry for mismatch repair proteins (with MLH1 promoter methylation analysis performed on MLH1‐deficient tumors) is found to be highly sensitive (85%) and specific (98%), missing only 2 patients of Lynch syndrome.

Immunohistochemistry (IHC) for mismatch repair (MMR) proteins is an established test to identify Lynch syndrome (LS) in patients with colorectal cancer and is being increasingly used to identify LS in women with endometrial and/or nonserous ovarian cancer (OC). We assessed interobserver agreement in the interpretation of MMR-IHC on endometrial and ovarian carcinomas. The study consisted of 73 consecutive endometrial cancers (n=48) and nonserous, nonmucinous epithelial OCs (n=25). Six pathologists from 2 cancer centers, one with and the other without, previous experience in interpreting MMR-IHC, evaluated MLH1, MSH2, MSH6, and PMS2 stains. Before the study, an experienced pathologist led a review of 9 teaching cases. A decision tool was developed as a guide in MMR-IHC interpretation. Staining was interpreted as intact, deficient, or equivocal for each protein. Interobserver agreement for the patient MMR status was categorized as "almost perfect" with κ=0.919 (95% CI, 0.863-0.976). All observers were in agreement in 66 (92%) tumors. Four of the less experienced pathologists had at least 1 discrepant interpretation. There were 6 discordant cases: 3 MMR-deficient cases and 2 MMR-intact cases by majority opinion were called equivocal by at least 1 observer, and 1 MMR-deficient case by majority opinion was interpreted as MMR intact by 1 pathologist. Only the latter case (1/73 patients, 1.4%) had an unequivocal disagreement that could affect patient management. Issues associated with discordant interpretation included heterogeneous staining, intratumoral lymphocytes, regional reduced internal control tissue staining, and scattered absent/weak staining adjacent to tumor cells with strong nuclear staining.

Background Despite recommendations for reflex immunohistochemistry (IHC) for mismatch repair (MMR) proteins to identify Lynch syndrome (LS), the uptake of genetic assessment by those who meet referral criteria is low. The authors implemented a comprehensive genetic navigation program to increase the uptake of genetic testing for LS in patients with endometrial cancer (EC) or nonserous/nonmucinous ovarian cancer (OC). Methods Participants with newly diagnosed EC or OC were prospectively recruited from 3 cancer centers in Ontario, Canada. Family history questionnaires were used to assess LS‐specific family history. Reflex IHC for MMR proteins was performed with the inclusion of clinical directives in pathology reports. A trained genetic navigator initiated a genetic referral on behalf of the treating physician and facilitated genetic referrals to the closest genetics center. Results A total of 841 participants (642 with EC, 172 with OC, and 27 with synchronous EC/OC) consented to the study; 194 (23%) were MMR‐deficient by IHC. Overall, 170 women (20%) were eligible for a genetic assessment for LS: 35 on the basis of their family history alone, 24 on the basis of their family history and IHC, 82 on the basis of IHC alone, and 29 on the basis of clinical discretion. After adjustments for participants who died (n = 6), 149 of 164 patients (91%) completed a genetic assessment, and 111 were offered and completed genetic testing. Thirty‐four women (4.0% of the total cohort and 30.6% of those with genetic testing) were diagnosed with LS: 5 with mutL homolog 1 (MLH1), 9 with mutS homolog 2 (MSH2), 15 with mutS homolog 6 (MSH6), and 5 with PMS2. Conclusions The introduction of a navigated genetic program resulted in a high rate of genetic assessment (>90%) in patients with gynecologic cancer at risk for LS., A navigated genetic system significantly increases the uptake of genetic assessment for women with endometrial and nonserous/nonmucinous ovarian cancers at high risk of Lynch syndrome.

Lung cancer is the leading cause of cancer mortality worldwide, with squamous cell carcinoma (SQCC) being the second most common form. SQCCs are thought to originate in bronchial basal cells through an injury response to smoking, which results in this stem cell population committing to hyperplastic squamous rather than mucinous and ciliated fates. Copy number gains in SOX2 in the region of 3q26–28 occur in 94% of SQCCs, and appear to act both early and late in disease progression by stabilizing the initial squamous injury response in stem cells and promoting growth of invasive carcinoma. Thus, anti-SOX2 targeting strategies could help treat early and/or advanced disease. Because SOX2 itself is not readily druggable, we sought to characterize SOX2 binding partners, with the hope of identifying new strategies to indirectly interfere with SOX2 activity. We now report the first use of proximity-dependent biotin labeling (BioID) to characterize the SOX2 interactome in vivo. We identified 82 high confidence SOX2-interacting partners. An interaction with the coactivator EP300 was subsequently validated in both basal cells and SQCCs, and we demonstrate that EP300 is necessary for SOX2 activity in basal cells, including for induction of the squamous fate. We also report that EP300 copy number gains are common in SQCCs and that growth of lung cancer cell lines with 3q gains, including SQCC cells, is dependent on EP300. Finally, we show that EP300 inhibitors can be combined with other targeted therapeutics to achieve more effective growth suppression. Our work supports the use of BioID to identify interacting protein partners of nondruggable oncoproteins such as SOX2, as an effective strategy to discover biologically relevant, druggable targets.

1523 Background: Abnormalities in mismatch repair (MMR) gene may be the result of pathogenic germline (Lynch syndrome) and somatic mutations as well as epigenetic events. Abnormalities in MMR have been described in non-serous/non-mucinous ovarian cancer (OC) but few studies have examined the causes of these MMR defects (MMRd). To address this, we have completed targeted mutational and methylation sequencing on MMRd OC cases. Methods: Women with newly diagnosed non-serous/mucinous OC (N = 215) were prospectively recruited from three cancer centers in Ontario, Canada between 2015-18. Tumors were reflexively assessed for MMR protein expression by immunohistochemistry. Tumor DNA was extracted from macrodissected MMRd cases and MMR-intact (MMRi) controls following pathology review. Matched tumor-normal samples were run on a custom NGS panel to identify germline and somatic mutations, copy number variants, rearrangements and promoter methylation in MMR and associated genes. Results: Of the 215 women enrolled in our study, 185 (86%) had OC alone and 30 (14%) had synchronous OC and endometrial cancer. Twenty-eight (13%) cases were MMRd, 11 of which were synchronous. The MMRd cohort had median age of 52.5 years, with mostly stage I (N = 14; 50%), grade 1 or 2 disease (N = 18; 64%) with endometrioid histotype (N = 18; 64%). One patient had recurrence after median follow-up of 33.6 months (13.2-93.6). There was no significant difference in overall/progression-free survival between the MMRd and MMRi patients. Using the NGS panel, Lynch syndrome (LS) was detected in 39% of MMRd cases (11/28; 7 OC and 4 synchronous): 7 MSH6, 2 MLH1, 1 PMS2, and 1 MSH2. Clinical germline sequencing was performed on all cases and verified panel findings. An explanation for the observed MMR phenotype was available for 18/20 deficient cases, including 9/10 MLH1−/PMS2− (7 somatic methylation, 1 bi-allelic somatic deletion, 1 germline mutation), 0/1 PMS2−, 6/7 MSH6− (6 germline mutations) and 2/2 MSH2−/MSH6− (1 germline mutation, 1 bi-allelic somatic mutation). Concordance between clinical and research panel sequencing results was 90%. None of the germline mutations were missed by the panel. Conclusions: Use of our custom NGS panel allows for the streamlined assessment of hereditary and somatic causes of MMR deficiency in OC and may be an attractive screening strategy for LS in this population.

Although cancers are considered stem cell diseases, mechanisms involving stem cell alterations are poorly understood. Squamous cell carcinoma (SQCC) is the second most common lung cancer, and its pathogenesis appears to hinge on changes in the stem cell behavior of basal cells in the bronchial airways. Basal cells are normally quiescent and differentiate into mucociliary epithelia. Smoking triggers a hyperproliferative response resulting in progressive premalignant epithelial changes ranging from squamous metaplasia to dysplasia. These changes can regress naturally, even with chronic smoking. However, for unknown reasons, dysplasias have higher progression rates than earlier stages. We used primary human tracheobronchial basal cells to investigate how copy number gains in SOX2 and PIK3CA at 3q26-28, which co-occur in dysplasia and are observed in 94% of SQCCs, may promote progression. We find that SOX2 cooperates with PI3K signaling, which is activated by smoking, to initiate the squamous injury response in basal cells. This response involves SOX9 repression, and, accordingly, SOX2 and PI3K signaling levels are high during dysplasia, while SOX9 is not expressed. By contrast, during regeneration of mucociliary epithelia, PI3K signaling is low and basal cells transiently enter a SOX2LoSOX9Hi state, with SOX9 promoting proliferation and preventing squamous differentiation. Transient reduction in SOX2 is necessary for ciliogenesis, although SOX2 expression later rises and drives mucinous differentiation, as SOX9 levels decline. Frequent coamplification of SOX2 and PIK3CA in dysplasia may, thus, promote progression by locking basal cells in a SOX2HiSOX9Lo state with active PI3K signaling, which sustains the squamous injury response while precluding normal mucociliary differentiation. Surprisingly, we find that, although later in invasive carcinoma SOX9 is generally expressed at low levels, its expression is higher in a subset of SQCCs with less squamous identity and worse clinical outcome. We propose that early pathogenesis of most SQCCs involves stabilization of the squamous injury state in stem cells through copy number gains at 3q, with the pro-proliferative activity of SOX9 possibly being exploited in a subset of SQCCs in later stages., A study of tracheobronchial basal cells reveals a mechanism by which lung squamous cell carcinoma is almost universally initiated by exploitation of a stem cell injury response involving SOX2 and PI3K., Author Summary Squamous cell carcinoma (SQCC) is a deadly and common form of lung cancer. How it develops from stem cells is poorly understood. SQCCs predominantly arise in bronchial epithelia, likely from basal cells, stem cells that normally generate mucinous and ciliated cells. Smoking, however, causes normally quiescent basal cells to proliferate and generate protective squamous epithelia. Continuous smoking eventually causes precancerous changes and, ultimately, SQCC. However, some precancerous changes regress to normal epithelia, suggesting that the natural stem cell injury response is not sustainable indefinitely. Here, we describe how the SOX2 transcription factor and PI3K signaling, which is activated by smoking, induce the squamous injury response in basal cells. We also provide evidence that regeneration of mucociliary epithelia after injury requires basal cells to enter a period of low SOX2 expression and PI3K signaling. Ninety-four percent of SQCCs have copy number gains in chromosome 3 that affect SOX2 and PIK3CA, a catalytic PI3K subunit. These gains occur at a point when precancerous tissue has an increased likelihood of progressing to SQCC. Our data suggest that SQCC is genetically initiated by events that sustain a normally self-limiting injury state, which forces stem cells to proliferate indefinitely in the presence of smoking-associated mutagens.

221 Background: In recent years, new treatments for chronic lymphocytic leukemia (CLL) with excellent response rates and varying toxicity profiles have emerged. In the setting of multiple available options, shared decision-making is critical. Developing strategies to enhance shared decision-making requires better understanding of how patients and providers make treatment decisions. Methods: Patients with CLL and health care providers within the University of Alabama at Birmingham Health System Cancer Community Network were to assess how treatment decisions are made. Results: Forty-four patients with CLL completed telephone-based surveys. The median age was 69 years old. Thirty percent had completed ≤12 years of education, 20% had some college education. Seventy-three percent of patients preferred an active or shared role in decision-making (27% preferring to make decision, 23% making decision with physician input, and 45% a shared role). Only 2% of patients preferred the doctor select the treatment. Despite >50% preferring an active role, only 20.5% perceived having an active role (Table 1). Thirty-three lay patient navigators, 26 oncologists, and 28 nurses (RN)/advanced care providers (ACP) completed web-based surveys. Navigators and nurses perceived a greater patient role in decision-making than physicians, who perceived that decisions were most often shared. Conclusions: Patients and providers have differing perceptions of their roles in decision-making in CLL treatment. Patients desire higher levels of participation in decision-making than they perceive that they receive, suggesting an opportunity for education of patients and providers to improve shared decision-making. [Table: see text]

201 Background: Patients with chronic lymphocytic leukemia (CLL) reporting high levels of distress due to knowledge gaps and emotional concerns can have negative outcomes and suffer from lower quality of life. Understanding patients’ activation levels, causes of distress, knowledge gaps, and psychosocial needs are crucial in high quality care. Optimally activated, educated and empowered patients are better positioned to communicate effectively with providers regarding selection of, and adherence to, CLL treatment protocols and long-term care plans, and potentially improving quality of life. Methods: We recruited 44 adults with CLL from the University of Alabama at Birmingham Health System Cancer Community Network from April to July of 2015 as part of an educational and quality improvement initiative. Patient-reported distress assessments were collected to evaluate distress levels and causes of distress. The Patient Activation Measure (PAM 13) was used to evaluate patient activation (1-4 scale with 4 maximally activated). Results: The median participant age was 69 years old (range 50-89 years). Thirty percent had completed ≤ 12 years of education, 20% had some college education. Thirty-nine percent were on active treatment, 59% were in observation; 2% were uncertain of treatment. Fifty seven percent of participants were maximally activated (level 4); 11% had an activation level of 3; 20% had a level of 2; and 11% had the lowest level of activation (level 1). Twenty-five percent reported moderate distress (≥ 4) and 5% reported severe distress (≥ 8); 34% reported distress due to psychosocial concerns and 25% due to knowledge gaps. Conclusions: This project demonstrates a need to improve patient activation levels and minimize patient distress related to knowledge gaps and psychosocial concerns related to CLL. Well-designed, easily accessible educational interventions and multi-level quality improvement programs may be helpful in improving patient engagement by providing necessary knowledge to improve patient-provider communication and optimize patient outcomes.

Background The large airways of the lungs (trachea and bronchi) are lined with a pseudostratified mucociliary epithelium, which is maintained by stem cells/progenitors within the basal cell compartment. Alterations in basal cell behavior can contribute to large airway diseases including squamous cell carcinomas (SQCCs). Basal cells have traditionally been thought of as a uniform population defined by basolateral position, cuboidal cell shape, and expression of pan-basal cell lineage markers like KRT5 and TP63. While some evidence suggests that basal cells are not all functionally equivalent, few heterogeneously expressed markers have been identified to purify and study subpopulations. In addition, few signaling pathways have been identified that regulate their cell behavior. The goals of this work were to investigate tracheal basal cell diversity and to identify new signaling pathways that regulate basal cell behavior. Methods We used flow cytometry (FACS) to profile cell surface marker expression at a single cell level in primary human tracheal basal cell cultures that maintain stem cell/progenitor activity. FACS results were validated with tissue staining, in silico comparisons with normal basal cell and lung cancer datasets, and an in vitro proliferation assay. Results We identified 105 surface markers, with 47 markers identifying potential subpopulations. These subpopulations generally fell into more (~ > 13%) or less abundant (~