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Artificial intelligence (AI) systems can improve cancer diagnosis, yet their development often relies on subjective histologic features as ground truth for training. Herein, we developed an AI model applied to histologic whole-slide images using CDH1 biallelic mutations, pathognomonic for invasive lobular carcinoma (ILC) in breast neoplasms, as ground truth. The model accurately predicted CDH1 biallelic mutations (accuracy = 0.95) and diagnosed ILC (accuracy = 0.96). A total of 74% of samples classified by the AI model as having CDH1 biallelic mutations but lacking these alterations displayed alternative CDH1 inactivating mechanisms, including a deleterious CDH1 fusion gene and noncoding CDH1 genetic alterations. Analysis of internal and external validation cohorts demonstrated 0.95 and 0.89 accuracy for ILC diagnosis, respectively. The latent features of the AI model correlated with human-explainable histopathologic features. Taken together, this study reports the construction of an AI algorithm trained using a genetic rather than histologic ground truth that can robustly classify ILCs and uncover CDH1 inactivating mechanisms, providing the basis for orthogonal ground truth utilization for development of diagnostic AI models applied to whole-slide image. Significance: Genetic alterations linked to strong genotypic-phenotypic correlations can be utilized to develop AI systems applied to pathology that facilitate cancer diagnosis and biologic discoveries., (©2024 American Association for Cancer Research.)

Small cell lung carcinoma (SCLC) is a highly aggressive malignancy that is typically associated with tobacco exposure and inactivation of RB1 and TP53 genes. Here we performed detailed clinicopathologic, genomic and transcriptomic profiling of an atypical subset of SCLC that lacked RB1 and TP53 co-inactivation and arose in never/light smokers. We found that most cases were associated with chromothripsis - massive, localized chromosome shattering - recurrently involving chromosomes 11 or 12, and resulting in extrachromosomal (ecDNA) amplification of CCND1 or co-amplification of CCND2/CDK4/MDM2, respectively. Uniquely, these clinically aggressive tumors exhibited genomic and pathologic links to pulmonary carcinoids, suggesting a previously uncharacterized mode of SCLC pathogenesis via transformation from lower-grade neuroendocrine tumors or their progenitors. Conversely, SCLC in never-smokers harboring inactivated RB1 and TP53 exhibited hallmarks of adenocarcinoma-to-SCLC derivation, supporting two distinct pathways of plasticity-mediated pathogenesis of SCLC in never-smokers.

Background: Racial disparities in outcomes exist in endometrial cancer (EC). The contribution of ancestry-based variations in germline pathogenic variants (gPVs) is unknown., Methods: Germline assessment of ≥76 cancer predisposition genes was performed in patients with EC undergoing tumor-normal Memorial Sloan Kettering Cancer Center Integrated Mutation Profiling of Actionable Cancer Targets sequencing from January 1, 2015 through June 30, 2021. Self-reported race/ethnicity and Ashkenazi Jewish ancestry data classified patients into groups. Genetic ancestry was inferred from Memorial Sloan Kettering Cancer Center Integrated Mutation Profiling of Actionable Cancer Targets. Rates of gPV and genetic counseling were compared by ancestry., Results: Among 1625 patients with EC, 216 (13%) had gPVs; 15 had >1 gPV. Rates of gPV varied by self-reported ancestry (Ashkenazi Jewish, 40/202 [20%]; Asian, 15/124 [12%]; Black/African American (AA), 12/171 [7.0%]; Hispanic, 15/124 [12%]; non-Hispanic (NH) White, 129/927 [14%]; missing, 5/77 [6.5%]; p = .009], with similar findings by genetic ancestry (p < .001). We observed a lower likelihood of gPVs in patients of Black/AA (odds ratio [OR], 0.44; 95% CI, 0.22-0.81) and African (AFR) ancestry (OR, 0.42; 95% CI, 0.18-0.85) and a higher likelihood in patients of Ashkenazi Jewish genetic ancestry (OR, 1.62; 95% CI; 1.11-2.34) compared with patients of non-Hispanic White/European ancestry, even after adjustment for age and molecular subtype. Somatic landscape influenced gPVs with lower rates of microsatellite instability-high tumors in patients of Black/AA and AFR ancestry. Among those with newly identified gPVs (n = 114), 102 (89%) were seen for genetic counseling, with lowest rates among Black/AA (75%) and AFR patients (67%)., Conclusions: In those with EC, gPV and genetic counseling varied by ancestry, with lowest rates among Black/AA and AFR patients, potentially contributing to disparities in outcomes given implications for treatment and cancer prevention., Plain Language Summary: Black women with endometrial cancer do worse than White women, and there are many reasons for this disparity. Certain genetic changes from birth (mutations) can increase the risk of cancer, and it is unknown if rates of these changes are different between different ancestry groups. Genetic mutations in 1625 diverse women with endometrial cancer were studied and the lowest rates of mutations and genetic counseling were found in Black and African ancestry women. This could affect their treatment options as well as their families and may make disparities worse., (© 2023 American Cancer Society.)

Purpose: To evaluate rates of germline pathogenic/likely pathogenic variants (PVs) and genetic counseling by ancestry in patients with epithelial ovarian cancer (EOC)., Methods: Patients with pathologically confirmed EOC who underwent clinical tumor-normal sequencing from January 1, 2015, to December 31, 2020, inclusive of germline analysis of ≥76 genes were included. Patients with newly identified PVs were referred for Clinical Genetics Service (CGS) counseling. Ancestry groups were defined using self-reported race/ethnicity and Ashkenazi Jewish (AJ) heritage. Genetic ancestry was inferred computationally using validated algorithms. Logistic regression models were built., Results: Of 1,266 patients, self-reported ancestry (AJ, 17%; Asian, 10%; Black/African American, 5.4%; Hispanic, 6.2%; non-Hispanic White, 57%; other, 0.16%; unknown, 4.0%) correlated with genetic ancestry (AJ ancestry, 18%; admixed, 10%; African, 4%; East Asian [EAS], 6%; European, 56%; Native American, 0.2%; South Asian [SAS], 4%; unknown, 2%). Germline PVs were observed in 313 (25%) patients, including 195 (15%) with PVs in EOC-associated genes. Those with PVs were younger at diagnosis (59 v 62 years; P < .001) and more likely to have high-grade serous ovarian cancer (83% v 72%; P = .009). PV prevalence varied between ancestry groups ( P < .001), with highest rates in the AJ (39.9%) and Asian (26.5%) groups and similar rates (>10%) across other ancestry groups. Use of genetic ancestry demonstrated similar findings and further characterized high rates of PV in EAS/SAS groups. Younger age, high-grade serous histology, and self-reported AJ or Asian ancestry were associated with PV in an EOC-associated gene. Rates of CGS counseling for newly identified PVs were high (80%) across ancestry groups., Conclusion: Rates of PV, particularly in EOC-associated genes, were high regardless of ancestry, with similar rates of counseling between groups, emphasizing the importance of universal genetic testing in all patients with EOC.

Background: We sought to determine the prevalence of germline pathogenic variants (gPVs) in unselected patients with endometrial cancer (EC), define biallelic gPVs within tumors, and describe their associations with clinicopathologic features., Methods: Germline assessment of at least 76 cancer predisposition genes was performed in patients with EC undergoing clinical tumor-normal Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets (MSK-IMPACT) sequencing from January 1, 2015, to June 30, 2021. In patients with gPVs, biallelic alterations in ECs were identified through analysis of loss of heterozygosity and somatic PVs. Clinicopathologic variables were compared using nonparametric tests., Results: Of 1625 patients with EC, 216 (13%) had gPVs, and 15 patients had 2 gPVs. There were 231 gPVs in 35 genes (75 [32%] high penetrance; 39 [17%] moderate penetrance; and 117 [51%] low, recessive, or uncertain penetrance). Compared with those without gPVs, patients with gPVs were younger (P = .002), more often White (P = .009), and less obese (P = .025) and had differences in distribution of tumor histology (P = .017) and molecular subtype (P < .001). Among 231 gPVs, 74 (32%) exhibited biallelic inactivation within tumors. For high-penetrance gPVs, 63% (47 of 75) of ECs had biallelic alterations, primarily affecting mismatch repair (MMR) and homologous recombination related genes, including BRCA1,BRCA2, RAD51D, and PALB2. Biallelic inactivation varied across molecular subtypes with highest rates in microsatellite instability-high (MSI-H) or copy-number (CN)-high subtypes (3 of 12 [25%] POLE, 30 of 77 [39%] MSI-H, 27 of 60 [45%] CN-high, 9 of 57 [16%] CN-low; P < .001)., Conclusions: Of unselected patients with EC, 13% had gPVs, with 63% of gPVs in high-penetrance genes (MMR and homologous recombination) exhibiting biallelic inactivation, potentially driving cancer development. This supports germline assessment in EC given implications for treatment and cancer prevention., (© The Author(s) 2023. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Cell free DNA (cfDNA) and circulating tumor cell free DNA (ctDNA) from blood (plasma) are increasingly being used in oncology for diagnosis, monitoring response, identifying cancer causing mutations and detecting recurrences. Circulating tumor RB1 DNA (ctDNA) is found in the blood (plasma) of retinoblastoma patients at diagnosis before instituting treatment (naïve). We investigated ctDNA in naïve unilateral patients before enucleation and during enucleation (6 patients/ 8 mutations with specimens collected 5-40 minutes from severing the optic nerve) In our cohort, following transection the optic nerve, ctDNA RB1 VAF was measurably lower than pre-enucleation levels within five minutes, 50% less within 15 minutes and 90% less by 40 minutes., Competing Interests: I have read the journal’s policy and the authors of this manuscript have the following completing interests: I.J.D. is a consultant or advisory board member for Apexigen, Astra-Zeneca, Bristol-Myers, Squibb/Celgene, Day One, Fennec, QED, and Roche. M.E.A declares the following competing interests: AstraZeneca, Bristol-Myers Squibb, Invivoscribe, Janssen Global Services, Merck, Roche (Consultant); Biocartis, Invivoscribe (Speaker/Speaker’s Bureau). D.W.Y.T. received honoraria from Nanodigmbio, Cowen and BoA Merrill Lynch; Research funding from ThermoFisher Scientific, EPIC Sciences, Prostate Cancer Foundation; Travel, Accommodations, Expenses from Nanodigmbio. D.W.Y.T is a co-inventor on a provisional patent application for systems and methods for detecting cancer via cfDNA screening (PCT/US2019/027487), and an inventor on a provisional patent application for systems and methods for distinguishing pathological mutations from clonal hematopoietic mutations in plasma cell-free DNA by fragment size analysis. D.W.Y.T is currently an employee of PetDx. Inc. M.F.B. declares research funding from Grail; personal fees from Roche and PetDX; and a provisional patent for systems and methods for detecting cancer via cfDNA screening (PCT/US2019/027487). D.H.A., D.L.M., A.R.B., R.B., J.H.F., D.N.F., M.F.W., G.J., N.S., P.K., M.L., M.S.D., M.A.R., D.H.L. declare no conflict of interest. This does not alter out adherence to PLOS ONE policies on sharing data and materials. There are no patents, products in development or marketed products associated with this research to declare., (Copyright: © 2023 Abramson et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Purpose: Microsatellite instability-high (MSI-H) endometrial carcinomas are underpinned by distinct mechanisms of DNA mismatch repair deficiency (MMR-D). We sought to characterize the clinical and genetic features of MSI-H endometrial cancers harboring germline or somatic mutations in MMR genes or MLH1 promoter hypermethylation (MLH1ph)., Experimental Design: Of > 1,100 patients with endometrial cancer that underwent clinical tumor-normal sequencing, 184 had MSI-H endometrial cancers due to somatic MMR mutations or MLH1ph, or harbored pathogenic germline MMR mutations. Clinicopathologic features, mutational landscape, and tumor-infiltrating lymphocyte (TIL) scores were compared among MMR-D groups using nonparametric tests. Log-rank tests were used for categorical associations; Kaplan-Meier method and Wald test based on Cox proportional hazards models were employed for continuous variables and survival analyses., Results: Compared with patients with germline (n = 25) and somatic (n = 39) mutations, patients with MLH1ph endometrial cancers (n = 120) were older (P < 0.001), more obese (P = 0.001) and had more advanced disease at diagnosis (P = 0.025). MLH1ph endometrial cancers were enriched for JAK1 somatic mutations as opposed to germline MMR-D endometrial cancers which showed enrichment for pathogenic ERBB2 mutations. MLH1ph endometrial cancers exhibited lower tumor mutational burden and TIL scores compared with endometrial cancers harboring germline or somatic MMR mutations (P < 0.01). MLH1ph endometrial cancer patients had shorter progression-free survival (PFS) on univariate analysis, but in multivariable models, stage at diagnosis remained the only predictor of survival. For stage I/II endometrial cancer, two-year PFS was inferior for patients with MLH1ph endometrial cancers compared with germline and somatic MMR groups (70% vs. 100%, respectively)., Conclusions: MLH1ph endometrial cancers likely constitute a distinct clinicopathologic entity compared with germline and somatic MMR-D ECs with potential treatment implications., (©2022 American Association for Cancer Research.)

Objectives: Endometrial stromal sarcomas (ESS) are rare, accounting for < 1% of all uterine malignancies. Treatment has been guided by small case series and retrospective studies. Endocrine therapy is used in both adjuvant and metastatic settings. Aromatase inhibitors (AIs) are widely used in clinical practice. We sought to evaluate clinical outcomes of AI use in the largest cohort of patients with LGESS to date., Methods: We performed a retrospective study of patients with LGESS treated with an AI at our institution from 1/1998-12/2020. Response was evaluated using RECIST 1.1. The Kaplan-Meier method was used to estimate median progression-free (PFS) and overall (OS) survival., Results: Forty patients were identified. Treatment was well tolerated, with 57.5% experiencing adverse effects. The most common were arthralgias (12 patients, 30%) and hot flashes (9, 22.5%). Two of 11 patients with RECIST-evaluable imaging experienced a partial response to treatment. Median PFS for the entire cohort was 79.2 months (95% CI 39.7 months to NE); the 5-year PFS rate was 59.6% (95% CI 41.8% to 73.6, p = 0.065). Median follow-up for the 29 survivors was 97.9 months (range: 12.6-226.7). The 5-year OS rate was 81.5% (95% CI 64.9-90.7%). One patient who discontinued AI after 10 years of treatment recurred 1 year later., Conclusion: AIs were well tolerated and offered periods of prolonged disease stability, even in the metastatic setting. Our study suggests, however, that response rates may be lower than previously reported. Data on optimal duration of treatment is needed, but the rarity of LGESS is an obstacle to conducting large clinical trials., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2022 The Author(s).)

Immune checkpoint blockade (ICB) has improved outcomes for patients with advanced cancer, but the determinants of response remain poorly understood. Here we report differential effects of mutations in the homologous recombination genes BRCA1 and BRCA2 on response to ICB in mouse and human tumors, and further show that truncating mutations in BRCA2 are associated with superior response compared to those in BRCA1. Mutations in BRCA1 and BRCA2 result in distinct mutational landscapes and differentially modulate the tumor-immune microenvironment, with gene expression programs related to both adaptive and innate immunity enriched in BRCA2-deficient tumors. Single-cell RNA sequencing further revealed distinct T cell, natural killer, macrophage, and dendritic cell populations enriched in BRCA2-deficient tumors. Taken together, our findings reveal the divergent effects of BRCA1 and BRCA2-deficiency on ICB outcome, and have significant implications for elucidating the genetic and microenvironmental determinants of response to immunotherapy.

Purpose: Circulating tumor DNA (ctDNA) is released by many tumors into the plasma. Its analysis has minimal procedural risk and, in many cancers, has the potential for clinical applications. In retinoblastoma, the clinical correlations of ctDNA in eyes treated without enucleation have not been studied. This purpose of this study was to determine how the ctDNA RB1 variant allele frequency (VAF) changes in patients with unilateral retinoblastoma after intra-arterial chemotherapy (IAC) treatment. Variant allele frequency is a proxy for tumor fraction., Design: Case series from a single tertiary cancer referral center., Participants: Five patients with retinoblastoma with at least 1 measurable ctDNA plasma specimen both at the time of active intraocular retinoblastoma before IAC and after at least 1 IAC cycle., Methods: Circulating tumor DNA RB1 was detected and VAF was measured before and after IAC treatment. Clinical correlations were made using clinical examination, fundus photography, ultrasound, and OCT., Main Outcome Measures: Comparison of ctDNA RB1 VAF before and after IAC treatment for retinoblastoma and concordance of ctDNA RB1 detectability with activity of intraocular disease., Results: Twenty-three ctDNA specimens were included from 5 patients. The 5 baseline RB1 VAFs ranged from 0.27% to 4.23%. In all patients, the subsequent post-intra-arterial RB1 VAF was lower than baseline (0.0%-0.17%). At 4 months (2 months after IAC completion), the ctDNA consistently was negative in the patients who demonstrated clinically inactive intraocular disease., Conclusions: In this small cohort, a decremental decrease in ctDNA RB1 VAF was found after IAC, suggesting that relative VAF changes could be a biomarker of treatment response., (© 2021 by the American Academy of Ophthalmology.)

Background: Radiation therapy is one of the most commonly used cancer therapeutics but genetic determinants of clinical benefit are poorly characterized. Pathogenic germline variants in ATM are known to cause ataxia-telangiectasia, a rare hereditary syndrome notable for marked radiosensitivity. In contrast, somatic inactivation of ATM is a common event in a wide variety of cancers, but its clinical actionability remains obscure., Methods: We analyzed 20 107 consecutively treated advanced cancer patients who underwent targeted genomic sequencing as part of an institutional genomic profiling initiative and identified 1085 harboring a somatic or germline ATM mutation, including 357 who received radiotherapy (RT). Outcomes of irradiated tumors harboring ATM loss-of-function (LoF) mutations were compared with those harboring variants of unknown significance. All statistical tests were 2-sided., Results: Among 357 pan-cancer patients who received 727 courses of RT, genetic inactivation of ATM was associated with improved radiotherapeutic efficacy. The 2-year cumulative incidence of irradiated tumor progression was 13.2% vs 27.5% for tumors harboring an ATM LoF vs variant of unknown significance allele, respectively (hazard ratio [HR] = 0.51, 95% confidence interval [CI] = 0.34 to 0.77, P = .001). The greatest clinical benefit was seen in tumors harboring biallelic ATM inactivation (HR = 0.19, 95% CI = 0.06 to 0.60, P = .005), with statistically significant benefit also observed in tumors with monoallelic ATM inactivation (HR = 0.57, 95% CI = 0.35 to 0.92, P = .02). Notably, ATM LoF was highly predictive of outcome in TP53 wild-type tumors but not among TP53-mutant tumors., Conclusions: We demonstrate that somatic ATM inactivation is associated with markedly improved tumor control following RT. The identification of a radio-sensitive tumor phenotype across multiple cancer types offers potential clinical opportunities for genomically guided RT., (© The Author(s) 2020. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

This investigation uses hybridization capture-based next-generation sequencing to deepen our understanding of genetics that underlie retinoblastoma. Eighty-three enucleated retinoblastoma specimens were evaluated using a MSK-IMPACT clinical next-generation sequencing panel to evaluate both somatic and germline alterations. Somatic copy number variations (CNVs) were also identified. Genetic profiles were correlated to clinicopathologic characteristics. RB1 inactivation was found in 79 (97.5%) patients. All specimens had additional molecular alterations. The most common non- RB1 gene alteration was BCOR in 19 (22.9%). Five (11.0%) had pathogenic germline mutations in other non- RB1 cancer predisposition genes. Significant clinicopathologic correlations included: vitreous seeds associated with 1q gains and 16q loss of heterozygosity (BH-corrected p -value = 0.008, 0.004; OR = 12.6, 26.7, respectively). BCOR mutations were associated with poor prognosis, specifically metastases-free survival (MFS) (nominal p -value 0.03). Furthermore, retinoblastoma patients can have non- RB1 germline mutations in other cancer-associated genes. No two specimens had the identical genetic profile, emphasizing the individuality of tumors with the same clinical diagnosis.

Mutations of Hepatocyte-Nuclear-Factor-1-Homeobox-A (HNF1A) gene and loss of Liver-Fatty-Acid-Binding-Protein (LFABP) are well documented in hepatocellular adenoma. However, the role of HNF1A mutations in hepatocellular carcinoma remains to be determined. In this study, all hepatocellular neoplasms evaluated by our institutional Memorial Sloan Kettering-Integrated Mutational Profiling of Actionable Clinical Targets assay or the Cancer Genome Atlas sequencing, and cases reported in the literature, were queried for HNF1A mutations. Together, 11 of 672 (1.6%) hepatocellular carcinomas harbored HNF1A mutations. The single case from our institution (n = 153) was extremely well differentiated, arising in a background of adenomatosis. Both the adenoma and carcinoma component contained the same 2 somatic HNF1A mutations (p. E32* and L214Q), with loss of LFABP. From the literature, 2 of 146 (1.4%) hepatocellular carcinomas had HNF1A mutations, and both arose in a background of adenomatosis. Information on pre-existing adenoma for the remaining cases (8/373, from The Cancer Genome Atlas) was not available. HNF1A mutations in carcinomas were associated with negative viral hepatitis status (p = .004), mutually exclusive with catenin beta-1 (CTNNB1) hotspot mutations, and trended to occur more in females (p = .06) and without cirrhosis (p = .03). Grade was not associated with HNF1A status (p = .28). Somatic HNF1A mutations occur in approximately 1% to 2% of hepatocellular carcinoma, often in a background of adenomatosis. Our findings suggest that malignant transformation of HNF1A-mutated hepatocellular adenoma occurs, albeit infrequently. Hepatocellular adenomas with HNF1A mutation or adenomatosis with loss of LFABP warrant thorough sampling and examination., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Purpose: Mutations in DNA mismatch repair (MMR) genes and PTEN, diagnostic of Lynch and Cowden syndromes, respectively, represent the only established inherited predisposition genes in endometrial cancer to date. The prevalence of other cancer predisposition genes remains unclear. We sought the prevalence of pathogenic germline variants in unselected patients with endometrial cancer attending for surgical consultation., Patients and Methods: Patients were prospectively consented (4/2016-5/2017) to an IRB-approved protocol of tumor-normal sequencing via a custom next-generation sequencing panel (MSK-IMPACT) with return of germline results for >75 cancer predisposition genes. Tumors were assessed for microsatellite instability (MSI). Per institutional standards, all tumors underwent Lynch syndrome screening via IHC for MMR proteins., Results: Of 156 patients who consented to germline genetic testing, 118 (76%) had stage I disease. Tumors were endometrioid in 104 (67%), of which 60 (58%) were grade 1. Twenty-four pathogenic germline variants were identified in 22 patients (14%)-7 (4.5%) with highly penetrant cancer syndromes and 15 (9.6%) with variants in moderate-, low-penetrance, or recessive genes. Of these, 5 (21%) were in Lynch syndrome genes (2 MSH6, 2 PMS2, and 1 MLH1) . All 5 tumors had concordant IHC staining; 2 (40%) were definitively MSI-high by next-generation sequencing. One patient had a known BRCA1 mutation; 1 had SMARCA4 deletion. The remaining 17 variants (71%) were incremental findings in moderate- and low-penetrance variants or genes associated with recessive disease., Conclusion: In unselected patients with predominantly low-risk, early-stage endometrial cancer, germline multi-gene panel testing identifies cancer predisposition gene variants in 14%. This finding may have implications for future cancer screening and risk-reduction recommendations. Universal IHC screening for Lynch syndrome successfully identifies the majority (71%) of high-penetrance germline mutations.

Importance: Although clonal hematopoiesis (CH) is well described in aging healthy populations, few studies have addressed the practical clinical implications of these alterations in solid-tumor sequencing., Objective: To identify and quantify CH-related mutations in patients with solid tumors using matched tumor-blood sequencing, and to establish the proportion that would be misattributed to the tumor based on tumor-only sequencing (unmatched analysis)., Design, Setting, and Participants: Retrospective analysis of samples from 17 469 patients with solid cancers who underwent prospective clinical sequencing of DNA isolated from tumor tissue and matched peripheral blood using the MSK-IMPACT assay between January 2014 and August 2017., Main Outcomes and Measures: We identified the presence of CH-related mutations in each patient's blood leukocytes and quantified the fraction of DNA molecules harboring the mutation in the corresponding matched tumor sample., Results: The mean age of the 17 469 patients with cancer at sample collection was 59.2 years (range, 0.3-98.9 years); 53.6% were female. We identified 7608 CH-associated mutations in the blood of 4628 (26.5%) patients. A total of 1075 (14.1%) CH-associated mutations were also detectable in the matched tumor above established thresholds for calling somatic mutations. Overall, 912 (5.2%) patients would have had at least 1 CH-associated mutation erroneously called as tumor derived in the absence of matched blood sequencing. A total of 1061 (98.7%) of these mutations were absent from population scale databases of germline polymorphisms and therefore would have been challenging to filter informatically. Annotating variants with OncoKB classified 534 (49.7%) as oncogenic or likely oncogenic., Conclusions and Relevance: This study demonstrates how CH-derived mutations could lead to erroneous reporting and treatment recommendations when tumor-only sequencing is used.

Given that all forms of Usher syndrome (USH) present with hearing loss in advance of retinal disease, the syndromic nature of the disorder is rarely appreciated when critical management decisions are being made. As a result, molecular diagnostics are crucial in guiding the management of USH patients. While 11 genes have been associated with USH, the USH2A gene is one of the largest contributors. Approximately 20% of suspected USH probands that undergo USH2A sequencing at our laboratory receive an inconclusive result due to the identification of a monoallelic disease-causing variant in USH2A. Many studies suggest that intragenic deletions and duplications represent an important USH2A variant type that can be missed by sequencing assays if supplemental algorithms or testing methods are not applied. To gain a comprehensive view of the contribution of USH2A CNVs to USH, we conducted prospective and retrospective screening in 700 hearing loss probands. Fourteen individuals with 11 unique USH2A CNVs are reported, including one pathogenic multi-exon duplication. Additionally, we mapped deletion breakpoints and performed a meta-analysis of USH2A CNVs to evaluate recurrence and underlying mechanisms. This analysis revealed breakpoint grouping within three introns, raising the possibility of CNV-susceptible regions within the gene. Overall, our data highlight the diversity of pathogenic CNVs in this gene, demonstrating that the comprehensive, high-resolution USH2A CNV analysis methods employed here are essential components of clinical genetic testing for USH., (Copyright © 2018 Elsevier Masson SAS. All rights reserved.)

Pathogenic germline variants in ataxia-telangiectasia mutated (ATM), a gene that plays a role in DNA damage response and cell cycle checkpoints, confer an increased breast cancer (BC) risk. Here, we investigated the phenotypic characteristics and landscape of somatic genetic alterations in 24 BCs from ATM germline mutation carriers by whole-exome and targeted sequencing. ATM-associated BCs were consistently hormone receptor positive and largely displayed minimal immune infiltrate. Although 79.2% of these tumors exhibited loss of heterozygosity of the ATM wild-type allele, none displayed high activity of mutational signature 3 associated with defective homologous recombination DNA (HRD) repair. No TP53 mutations were found in the ATM-associated BCs. Analysis of an independent data set confirmed that germline ATM variants and TP53 somatic mutations are mutually exclusive. Our findings indicate that ATM-associated BCs often harbor bi-allelic inactivation of ATM, are phenotypically distinct from BRCA1/2-associated BCs, lack HRD-related mutational signatures, and that TP53 and ATM genetic alterations are likely epistatic.

Tumor molecular profiling is a fundamental component of precision oncology, enabling the identification of genomic alterations in genes and pathways that can be targeted therapeutically. The existence of recurrent targetable alterations across distinct histologically defined tumor types, coupled with an expanding portfolio of molecularly targeted therapies, demands flexible and comprehensive approaches to profile clinically relevant genes across the full spectrum of cancers. We established a large-scale, prospective clinical sequencing initiative using a comprehensive assay, MSK-IMPACT, through which we have compiled tumor and matched normal sequence data from a unique cohort of more than 10,000 patients with advanced cancer and available pathological and clinical annotations. Using these data, we identified clinically relevant somatic mutations, novel noncoding alterations, and mutational signatures that were shared by common and rare tumor types. Patients were enrolled on genomically matched clinical trials at a rate of 11%. To enable discovery of novel biomarkers and deeper investigation into rare alterations and tumor types, all results are publicly accessible.

B-cell lymphomas with MYC rearrangement are a heterogeneous and unique group of neoplasms that may behave aggressively, especially in conjunction with other oncogenic alterations that cooperate with MYC, warranting early and intensive treatment in a subset of patients. Identification of MYC-rearranged B-cell lymphomas by immunophenotypic analysis could help guide cytogenetic work-up, as well as expedite therapeutic interventions. Using flow cytometry we analyzed the expression of CD10, CD19, CD20, CD38 and CD45 in 53 patients with three distinct neoplasms with MYC rearrangements: Burkitt lymphoma (n = 12), double hit lymphoma (n = 17) and diffuse large B-cell lymphoma (DLBCL) with MYC rearrangement (n = 8). The expression profile of these commonly used antibodies was similar among these three groups. The antigenic pattern of bright CD38 and dim CD45 was unique to the MYC-rearranged neoplasms when compared to non-MYC-rearranged aggressive DLBCL (n = 16), with a combined sensitivity of 67% and specificity of 100%, suggesting a shared underlying biology among these MYC rearranged B-cell lymphomas.

The Partners HealthCare system's Clinical Fellowship in Pathology Informatics (Boston, MA, USA) faces ongoing challenges to the delivery of its core curriculum in the forms of: (1) New classes of fellows annually with new and varying educational needs and increasingly fractured, enterprise-wide commitments; (2) taxing electronic health record (EHR) and laboratory information system (LIS) implementations; and (3) increasing interest in the subspecialty at the academic medical centers (AMCs) in what is a large health care network. In response to these challenges, the fellowship has modified its existing didactic sessions and piloted both a network-wide pathology informatics lecture series and regular "learning laboratories". Didactic sessions, which had previously included more formal discussions of the four divisions of the core curriculum: Information fundamentals, information systems, workflow and process, and governance and management, now focus on group discussions concerning the fellows' ongoing projects, updates on the enterprise-wide EHR and LIS implementations, and directed questions about weekly readings. Lectures are given by the informatics faculty, guest informatics faculty, current and former fellows, and information systems members in the network, and are open to all professional members of the pathology departments at the AMCs. Learning laboratories consist of small-group exercises geared toward a variety of learning styles, and are driven by both the fellows and a member of the informatics faculty. The learning laboratories have created a forum for discussing real-time and real-world pathology informatics matters, and for incorporating awareness of and timely discussions about the latest pathology informatics literature. These changes have diversified the delivery of the fellowship's core curriculum, increased exposure of faculty, fellows and trainees to one another, and more equitably distributed teaching responsibilities among the entirety of the pathology informatics asset in the network. Though the above approach has been in place less than a year, we are presenting it now as a technical note to allow for further discussion of evolving educational opportunities in pathology informatics and clinical informatics in general, and to highlight the importance of having a flexible fellowship with active participation from its fellows.

PGP9.5/UCHL1 is a member of the carboxyl-terminal ubiquitin hydrolase family with a potential role in carcinogenesis. We previously identified PGP9.5 as a putative tumor-suppressor gene and methylation of the promoter as a cancer-specific event in primary cancer tissues. In this current study, we analyzed PGP9.5 methylation in 50 esophageal squamous cell carcinoma (ESCC) primary tumors with well characterized clinicopathologic variables including patient outcome. Two independent modalities for methylation analysis (TaqMan methylation-specific PCR and combined bisulfite restriction analysis) were used to analyze these samples. The two data sets were consistent with each other, as the 21 patients (42%) with highest methylation levels by TaqMan analysis all showed visible combined bisulfite restriction analysis bands on acrylamide gels. Using an optimized cutoff value by TaqMan quantitation, we found that patients with higher PGP9.5 methylation ratios in the primary tumor showed poorer 5-year survival rates than those without PGP9.5 methylation (P = 0.01). A significant correlation was also seen between PGP9.5 promoter methylation and the presence of regional lymph node metastases (P = 0.03). Multivariate analysis subsequently revealed that PGP9.5 methylation was an independent prognostic factor for ESCC survival (P = 0.03). These results suggest that PGP9.5 promoter methylation could be a clinically applicable marker for ESCC progression.