Faculty Bibliography

Endometrial carcinoma (EC), as described by Bokhman, has historically been classified as Type I (low-grade, hormone-dependant, young patients, good prognosis) or Type II (high-grade, hormone-independent, older patients, poor prognosis). This classification is no longer pragmatic, however, as EC is a much more heterogeneous disease. Four molecular subtypes of EC were identified by The Cancer Genome Atlas (TCGA), and subsequent studies have demonstrated its utility in predicting prognosis. While endometrial serous carcinoma (ESC), the prototypical Type II EC, largely occurs in older women, younger women with ESC were not accounted for in the Bokhman model and were underrepresented in the TCGA study. We hypothesized that a subset of ESCs in young patients do not represent bona fide serous carcinomas but rather high-grade endometrioid carcinomas mimicking a serous phenotype. We identified ESCs and mixed endometrioid/serous carcinomas in women <60 years (n=37), and analyzed their clinical, morphologic, immunohistochemical, and molecular characteristics. Sixteen percent showed mismatch repair deficiency (MMR-D) and 11% were diagnosed with Lynch syndrome. Additionally, 16% of cases tested harbored a hotspot POLE exonuclease domain mutation (POLE-EDM). Morphologically, 47% of tumors showed confirmatory endometrioid features, including atypical hyperplasia, a low-grade endometrioid carcinoma component, or squamous differentiation. Clinically, the overall survival in patients with MMR-D and POLE-EDM was significantly better than that of patients without these features (P=0.0329). In conclusion, ESCs in young patients comprise a heterogeneous group of tumors, demonstrating diverse clinical, immunohistochemical, morphologic, and molecular features which have implications for prognosis and adjuvant therapy.

Background: The NCCN currently recommends microsatellite instability (MSI) or mismatch repair (MMR) immunohistochemistry (IHC) for patients with endometrial cancer (EC) as a screen for Lynch Syndrome and criteria for immune checkpoint inhibitor therapy. Recently, MSI testing has become available through next generation sequencing (NGS). We sought to compare the concordance of MMR IHC and MSI status obtained via NGS in EC.
Design(s): Patients with newly diagnosed primary EC were prospectively consented to an IRB-approved protocol. ECs were subjected to MMR IHC and targeted NGS with a panel covering over 400 cancer-related genes. MSIsensor was used to bioinformatically infer the MSI status, with an MSIsensor score >=10 deemed MSI-high. Tumor cell content was inferred bioinformatically using ABSOLUTE. Concordance between IHC and sequencing results was defined using Cohen's Kappa.
Result(s): 175 ECs were included (116 endometrioid, 17 serous, 11 carcinosarcoma, 13 mixed, 6 clear cell, 7 dedifferentiated, 5 other). 50 (29%) were considered MMRd based on the loss of at least one MMR protein by IHC, of which 30 (60%) ECs were classified as MSI-high by MSIsensor (Table). Of the 125 ECs with retained MMR expression, the vast majority (123; 98%) was molecularly concordant and was not MSI-high (Table). The overall agreement between MMRd and MSI-high by MSIsensor was 153/175 (87%), with a Kappa of 0.749 (good agreement). Of the 20 MMRd classified as non-MSI-high, 9 were MSI indeterminate and 11 microsatellite stable. Of these 11 discrepant ECs (i.e. MMRd and microsatellite stable), 4 displayed loss of MLH1 and PMS2 expression, 1 PMS2 loss and 6 MSH6 loss of expression (Table). The tumor purity was significantly lower in the 20 MMRd non-MSI-high ECs (median 26%, range 19-60%) compared to the 30 MMRd MSI-high concordant ECs (median 49%, range 20-95%; p<0.001). (Table presented)
Conclusion(s): Our findings revealed a good agreement between MMR IHC and MSI status inferred from NGS for EC. Tumor purity may falsely decrease the degree of MSI in EC. However, in addition to MSI status, multi-gene sequencing assays provide information on specific somatic/ germline mutations, copy number alterations and tumor mutational burden in a single assay

Background: Molecular screening for therapeutically targetable alterations is considered standard of care in the management of non-small cell lung cancer. However, most molecular assays utilize tumor tissue, which may not always be available. This has led to the development of "liquid biopsies": Plasma-based Next Generation Sequencing (NGS) tests that use circulating tumor DNA as a substrate to identify relevant targets. In this study, we sought to determine the level of agreement between the two tests as they are used in clinical practice and to investigate the utility of concurrent plasma/tissue testing.
Design(s): We identified 47 cases of lung adenocarcinoma diagnosed over the past 2 years, who received concurrent testing (within 24 weeks) with both our institution's tissue (DNA and RNA based) NGS assay and a commercial plasma-based NGS assay. The results were reviewed to establish concordance in the identification of mutations or fusions deemed clinically relevant or for which a targeted therapy was available.
Result(s): Patients in our cohort represented both new diagnoses (31 cases, 66%) and disease progression on treatment (16 cases, 34%). The majority (83%) had stage 4 disease. Tissue NGS identified clinically relevant mutations in 39 cases (83%), including in 14 (88%) of the previously treated cases. By comparison, plasma NGS identified clinically relevant mutations in 20 cases (43%, p<0.001), including 6 treated cases (38%, p=0.01). Tissue NGS identified therapeutic targets in 55% of cases and 75% of previously treated cases; while plasma NGS identified targets in 28% and 25% respectively (p<0.001 and p=0.01 respectively). All clinically relevant mutations identified by plasma NGS were also detected by tissue NGS, while plasma NGS detected only 51% those identified by tissue NGS. Discrepant cases involved hotspot mutations and actionable fusions including those in EGFR, KRAS, and ROS1 (Table 1).(Table presented)
Conclusion(s): Tissue NGS detects more clinically relevant alterations and therapeutic targets compared to plasma NGS, especially in the post-treatment setting, suggesting that tissue NGS should be the preferred method for molecular testing of lung adenocarcinoma. Additionally, all clinically relevant mutations identified by plasma NGS were also detected by tissue NGS, suggesting that tissue/plasma cotesting provides little additional benefit over tissue NGS alone. Plasma NGS can detect clinically relevant targets, and still plays an important role when tissue testing is impractical or not possible

Background: For the clinical identification of the four molecular subtypes of endometrial cancer (EC), which were originally identified using whole-exome sequencing, surrogates employing immunohistochemistry (IHC) have been implemented. In this surrogate, p53 IHC is used to identify 'copy-number high'/ p53 abnormal ECs. We sought to define the concordance of p53 IHC and TP53 mutation status in ECs.
Design(s): Patients with newly diagnosed primary EC were prospectively consented to an IRB-approved protocol. ECs were subjected to p53 and DNA mismatch repair (MMR) protein IHC and to massively parallel sequencing targeting 410-468 cancer-related genes. ECs were classified based on POLE mutation status and MMR and p53 IHC into the four molecular subtypes: POLE (ultramutated), MMRdeficient, copy-number low (endometrioid) and copy-number high (serous-like). Concordance between p53 IHC and somatic TP53 mutation status was defined using Cohen's Kappa.
Result(s): 175 ECs were included in this study (116 endometrioid, 17 serous, 11 carcinosarcoma, 13 mixed, 6 clear cell, 7 dedifferentiated, 5 other). 41 (23%) ECs demonstrated aberrant p53 expression by IHC, and of these 36 (88%) harbored a somatic TP53 mutation (Table). Of the 134 ECs with normal/ wild-type p53 protein expression by IHC, the majority of ECs (115; 86%) were molecularly concordant and did not harbor a somatic TP53 mutation (Table). The agreement between the two methods was 151/175 (86%), with a Kappa of 0.726 (good agreement). The sensitivity and specificity of p53 IHC for the detection of pathogenic TP53 mutations was 66% and 96%, respectively. In total, there were 24 (14%) discrepant cases, which had aberrant p53 IHC in the absence of a TP53 mutation (n=5) or a TP53 mutation but normal p53 protein expression patterns (n=19). Of the 19 TP53-mutant ECs with normal p53 IHC, 10 harbored nonpathogenic TP53 mutations, 3 harbored subclonal TP53 hotspot mutations, 3 had subclonal TP53 loss of function mutations, and only 3 had clonal TP53 hotspot mutations (Table). Discrepancies were primarily observed in ECs of MMR-deficient (9/19) or POLE (4/19) EC subtypes. (Table presented)
Conclusion(s): Our findings demonstrate a good concordance between p53 IHC and TP53 mutation status in EC. p53 IHC is a specific and fairly sensitive surrogate for pathogenic TP53 mutations. The type and clonality of TP53 mutations explain the vast majority of discrepancies between sequencing and IHC assessment of TP53

We undertook a comprehensive proteogenomic characterization of 95 prospectively collected endometrial carcinomas, comprising 83 endometrioid and 12 serous tumors. This analysis revealed possible new consequences of perturbations to the p53 and Wnt/β-catenin pathways, identified a potential role for circRNAs in the epithelial-mesenchymal transition, and provided new information about proteomic markers of clinical and genomic tumor subgroups, including relationships to known druggable pathways. An extensive genome-wide acetylation survey yielded insights into regulatory mechanisms linking Wnt signaling and histone acetylation. We also characterized aspects of the tumor immune landscape, including immunogenic alterations, neoantigens, common cancer/testis antigens, and the immune microenvironment, all of which can inform immunotherapy decisions. Collectively, our multi-omic analyses provide a valuable resource for researchers and clinicians, identify new molecular associations of potential mechanistic significance in the development of endometrial cancers, and suggest novel approaches for identifying potential therapeutic targets.

Fumarate hydratase (FH) mutations underpin the autosomal recessive syndrome. FH deficiency and the autosomal dominant syndrome hereditary leiomyomatosis and renal cell carcinoma (HLRCC). The FH c.1431_1433dupAAA (p.Lys477dup) genomic alteration has been conclusively shown to contribute to FH deficiency when occurring with another FH germline alteration. However, a sufficiently large dataset has been lacking to conclusively determine its clinical significance to cancer predisposition in the heterozygous state. We reviewed a series of 7,571 patients with cancer who received germline results through MSK-IMPACT testing at the Memorial Sloan Kettering Cancer Center. The FH c.1431_1433dupAAA (p.Lys477dup) variant was detected in 24 individuals, none of whom was affected with renal cancer. Eleven of the 372 patients with renal cancer were identified to carried pathogenic FH variants associated with HLRCC. None of these 372 patients with renal cancer carried the FH c.1431_1433dupAAA variant. Our data indicate the FH c.1431_1433dupAAA is not associated with cancer including renal cell carcinoma.

OBJECTIVES/OBJECTIVE:Assess outcomes of a clinical cohort of patients with endometrioid endometrial cancer (EEC) harboring somatic POLE exonuclease domain mutations (EDMs). METHODS:Patients were consented to a protocol of tumor-normal massively parallel sequencing of 410-468 cancer related genes. EECs subjected to sequencing from 2014 to 2018 were reviewed. Tumors with somatic POLE EDMs were identified. EECs were assessed for microsatellite instability (MSI) using MSIsensor and immunohistochemical analysis for mismatch repair (MMR) proteins. RESULTS:Of the 451 EECs sequenced, 23 had a POLE EDM (5%): 20 primary and 3 recurrent tumors sequenced. Nineteen cases (83%) were stage I/II and 4 (17%) were stages III/IV. Thirteen EECs (57%) were of FIGO grades 1/2, 10 (43%) grade 3. All patients were treated with surgery and 17 (89%) received adjuvant therapy. Five (22%) demonstrated loss of DNA MMR protein expression, none were due to Lynch syndrome. MSIsensor scores were conclusive for 21 samples: 19 were microsatellite stable and 2 MSI-high. After median follow-up of 30 months, 4/23 (17%) developed recurrences: 3 with initial grade 3 stage I and 1 with grade 1 stage III disease. One patient with grade 2 stage IV EEC had progressive disease after treatment. CONCLUSIONS:Patients with POLE EDM EEC have been shown to have a favorable prognosis. In this real-world cohort of patients, de novo metastatic disease and recurrences in initially uterine-confined cases were observed. Further research is warranted before incorporating the presence of POLE EDM into decision-making regarding adjuvant therapy.