Abstract 6499: Towards a combined immunohistochemistry-based subtyping of ovarian endometrioid carcinoma

Background: Ovarian endometrioid carcinoma (OEC) is an uncommon, understudied histotype that is distinguished from other histotypes by unique genomic features and high hormone receptor expression. There is growing interest in the biological relevance of subtyping using immunohistochemistry (IHC).

Methods: Women with primary invasive OEC diagnosed from 1989 to 2010 were retrospectively identified from the population-based Alberta Cancer Registry, Canada. Pathology slide review and IHC staining for Napsin A, TP53, and WT1 were used to reduce histologic misclassification, resulting in N=166 participants (low-stage N=138, high-stage N=28), excluding those who received neo-adjuvant chemotherapy. The following markers were stained and scored on tissue microarrays: TP53 (normal/abnormal), PMS2/MSH6 (mismatch repair proficient [MMRp]/deficient [MMRd]), PGR (loss/retained), and CTNNB1 (nuclear/cytoplasmic). Using a hierarchical decision tree by stage group (low/high), we categorized tumors as TP53 abnormal, MMRd, PGR loss, nuclear CTNNB1, and no specific immunohistochemical profile (NSIP). Distributions and five-year disease specific survival (DSS) was estimated for each group; hazard ratios (HRs) adjusted for age were estimated using Cox regression with NSIP as referent group.

Results: Among low-stage cases, five-year survival was as follows: 80% for TP53 abnormal (N=10, 7%), 87% for MMRd (N=15, 11%), 80% for PGR loss (N=10, 7%), 98% for nuclear CTNNB1 (N=63, 46%), and 95% for NSIP group (N=40, 29%). Overall, IHC group was associated with DSS among low stage cases (LRT p-value=0.006), and the group with nuclear CTNNB1 had a small but statistically significant DSS advantage (HR=0.089, 95% CI 0.011-0.742, p=0.025). TP53 and PGR loss suggested shorter DSS than the referent NSIP group, but not statistically significantly so (HR=1.26 and 3.08, respectively). Among high-stage cases, five-year DSS was as follows: 57% for TP53 abnormal (N=7, 25%), 75% for MMRd (N=8, 29%), 33% for nuclear CTNNB1 (N=3, 11%), and 17% for NSIP (N=10, 36%). There were no high-stage cases in the PGR-loss group. Nuclear CTNNB1 group had a shorter DSS among high-stage cases, but this was not statistically significantly so (HR=1.16, p=0.85).

Conclusion: Pending replication in additional datasets, results suggest that OEC cases in nuclear CTNNB1 or NSIP IHC groups may have a favorable prognosis in which de-escalation of therapy can be considered. In addition, abnormal TP53 and loss of PGR may identify a high-risk subset of low-stage OEC.

Citation Format: Brooke Jorgensen, Stacey Winham, Julie Cunningham, Sebastian Armasu, Chen Wang, Hunter Atkinson, Bryan McCauley, Linda Kelemen, Martin Koebel, Ellen Goode. Towards a combined immunohistochemistry-based subtyping of ovarian endometrioid carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6499.

The genomic and immune landscape of long-term survivors of high-grade serous ovarian cancer

Fewer than half of all patients with advanced-stage high-grade serous ovarian cancers (HGSCs) survive more than five years after diagnosis, but those who have an exceptionally long survival could provide insights into tumor biology and therapeutic approaches. We analyzed 60 patients with advanced-stage HGSC who survived more than 10 years after diagnosis using whole-genome sequencing, transcriptome and methylome profiling of their primary tumor samples, comparing this data to 66 short- or moderate-term survivors. Tumors of long-term survivors were more likely to have multiple alterations in genes associated with DNA repair and more frequent somatic variants resulting in an increased predicted neoantigen load. Patients clustered into survival groups based on genomic and immune cell signatures, including three subsets of patients with BRCA1 alterations with distinctly different outcomes. Specific combinations of germline and somatic gene alterations, tumor cell phenotypes and differential immune responses appear to contribute to long-term survival in HGSC.

Low incidence of primary biliary cirrhosis (PBC) in the first-degree relatives of PBC probands after 8 years of follow-up

BACKGROUND & AIMS

Primary biliary cirrhosis (PBC) is characterized by chronic cholestasis and disease-specific antimitochondrial antibodies (AMA). A high prevalence of AMAs in first-degree relatives (FDRs) of PBC probands has been reported, although the natural history of such patients has not been described. We aimed to assess the risk of developing PBC in AMA+ FDRs of patients with PBC.

METHODS

First-degree relatives recruited to the Mayo Clinic PBC Genetic Epidemiology Registry and Biorepository were followed for disease onset after recruitment. Development of PBC was ascertained via self-report during a telephone interview and/or via proband report on a questionnaire. Chi-squared test and t-test were used to assess the differences between categorical and continuous variables respectively. A mixed-effects model was used to assess the change in biochemical profiles over time.

RESULTS

Forty AMA+ and 423 AMA- subjects were included and followed for a median of 8.9 and 8.4 years respectively. Overall, 3% (n = 15) of FDRs were diagnosed with PBC, and AMA+ FDRs had a higher risk than AMA- FDRs (24% vs. 0.7%, P < 0.01). However, among undiagnosed FDRs, only 4% of AMA+ (n = 1) and 0.4% of AMA- (n = 1) FDRs were diagnosed with PBC (P = 0.17) during the follow-up period. None of the AMA+ FDRs with normal alkaline phosphatase at baseline developed PBC in follow-up.

CONCLUSIONS

Our results suggest a low risk of developing PBC over time in FDRs of patients with PBC, particularly those without biochemical evidence of cholestasis at baseline. These data are useful in counselling and reassuring relatives of their overall favourable prognosis.

22-Mb integrated physical and genetic map based on YAC/STS content spanning the interval DXS1125-DXS95 in human Xq12-q21.31

A YAC/STS map has been assembled spanning 22 Mb across Xq12-q21.31, between markers DXS1125 and DXS95. In addition to the landmark loci for the X-inactivation center XIST and the ATRX, ATP7A, phosphoglycerate kinase, POU3F4, and choroideremia genes, the candidate disease gene regions for torsion dystonia 3 and two X-linked mental retardation syndromes are included. Also, the human voltage-dependent anion channel gene (HVDAC1) has been placed near DXS986. The current map incorporates 211 YACs from five different libraries, formatted with 185 STSs that comprise 26 genetic linkage markers, 60 newly-developed YAC-end STSs, and eight ESTs. The multiple clone coverage and average resolution of one STS per 120 kb provide resources for disease gene searches and are facilitating complete sequencing of the region.

X chromosome map at 75-kb STS resolution, revealing extremes of recombination and GC content

A YAC/STS map of the X chromosome has reached an inter-STS resolution of 75 kb. The map density is sufficient to provide YACs or other large-insert clones that are cross-validated as sequencing substrates across the chromosome. Marker density also permits estimates of regional gene content and a detailed comparison of genetic and physical map distances. Five regions are detected with relatively high G + C, correlated with gene richness; and a 17-Mb region with very low recombination is revealed between the Xq13.3 [XIST] and Xq21.3 XY homology loci.

Incorporation of the Arden Syntax within the reimplementation of a closed-loop decision support system

The initial implementation of a clinical decision support system, although extremely successful and popular with users, suffered from response time and operational support difficulties. As part of the redesign of the system, which uses closed-loop rules to propose laboratory and other investigations, the decision was taken to move to Arden Syntax for the expression of such rules, although in some areas the current standard was felt to be either inadequate or inelegant. Such limitations have been overcome by the development of local extensions to the Arden Syntax, which are described and where appropriate proposed as possible enhancements of the standard. The use of common UNIX tools in the creation of a compiler which converts Arden Medical Logic Modules to M (MUMPS) code is also discussed.

Computerised protocols for laboratory investigation and their effect on use of medical time and resources

AIMS

To devise a computerised management system protocol which not only proposes the laboratory investigations to be performed on each patient but also performs related clinical functions.

METHODS

The system was designed by senior members of staff. The protocols defined all laboratory investigations including haematology, biochemistry, immunology and cross-matching, and included static and dynamic rules. Patients can be changed to different or additional protocols, as required; likewise proposed tests can be deleted or added. The software is written in MUMPS and runs on a 386 PC running MSM MUMPS under MSDOS.

RESULTS

The number of clinical chemistry tests requested per patient per day fell by 9.5% (p less than 0.01) for transplant recipients and by 28.8% (p less than 0.01) for non-transplant recipients. The average time spent by junior medical staff requesting laboratory investigations and enquiring about results fell from 10 minutes per patient per day to 4.1 minutes (p less than 0.001).

CONCLUSIONS

The introduction of this system in no way abrogates clinicians' responsibility for the management of patients, because all proposed investigations must be confirmed or modified by the authorising doctor. The system allows for the audit of requesting patterns and subsequent improvement in protocols by recording any alterations made to the proposed investigations. Significant benefits in terms of better use of house officer time and medical resources were also achieved.