Genomic characterization of metastatic patterns from prospective clinical sequencing of 25,000 patients.

Metastatic progression is the main cause of death in cancer patients, whereas the underlying genomic mechanisms driving metastasis remain largely unknown. Here, we assembled MSK-MET, a pan-cancer cohort of over 25,000 patients with metastatic diseases. By analyzing genomic and clinical data from this cohort, we identified associations between genomic alterations and patterns of metastatic dissemination across 50 tumor types. We found that chromosomal instability is strongly correlated with metastatic burden in some tumor types, including prostate adenocarcinoma, lung adenocarcinoma, and HR+/HER2+ breast ductal carcinoma, but not in others, including colorectal cancer and high-grade serous ovarian cancer, where copy-number alteration patterns may be established early in tumor development. We also identified somatic alterations associated with metastatic burden and specific target organs. Our data offer a valuable resource for the investigation of the biological basis for metastatic spread and highlight the complex role of chromosomal instability in cancer progression.

Pharmacologic modulation of RNA splicing enhances anti-tumor immunity.

Although mutations in DNA are the best-studied source of neoantigens that determine response to immune checkpoint blockade, alterations in RNA splicing within cancer cells could similarly result in neoepitope production. However, the endogenous antigenicity and clinical potential of such splicing-derived epitopes have not been tested. Here, we demonstrate that pharmacologic modulation of splicing via specific drug classes generates bona fide neoantigens and elicits anti-tumor immunity, augmenting checkpoint immunotherapy. Splicing modulation inhibited tumor growth and enhanced checkpoint blockade in a manner dependent on host T cells and peptides presented on tumor MHC class I. Splicing modulation induced stereotyped splicing changes across tumor types, altering the MHC I-bound immunopeptidome to yield splicing-derived neoepitopes that trigger an anti-tumor T cell response in vivo. These data definitively identify splicing modulation as an untapped source of immunogenic peptides and provide a means to enhance response to checkpoint blockade that is readily translatable to the clinic.

Heterogeneous Tumor-Immune Microenvironments among Differentially Growing Metastases in an Ovarian Cancer Patient.

We present an exceptional case of a patient with high-grade serous ovarian cancer, treated with multiple chemotherapy regimens, who exhibited regression of some metastatic lesions with concomitant progression of other lesions during a treatment-free period. Using immunogenomic approaches, we found that progressing metastases were characterized by immune cell exclusion, whereas regressing and stable metastases were infiltrated by CD8+ and CD4+ T cells and exhibited oligoclonal expansion of specific T cell subsets. We also detected CD8+ T cell reactivity against predicted neoepitopes after isolation of cells from a blood sample taken almost 3 years after the tumors were resected. These findings suggest that multiple distinct tumor immune microenvironments co-exist within a single individual and may explain in part the heterogeneous fates of metastatic lesions often observed in the clinic post-therapy. VIDEO ABSTRACT.

Fundamental immune-oncogenicity trade-offs define driver mutation fitness.

Missense driver mutations in cancer are concentrated in a few hotspots1. Various mechanisms have been proposed to explain this skew, including biased mutational processes2, phenotypic differences3-6 and immunoediting of neoantigens7,8; however, to our knowledge, no existing model weighs the relative contribution of these features to tumour evolution. We propose a unified theoretical 'free fitness' framework that parsimoniously integrates multimodal genomic, epigenetic, transcriptomic and proteomic data into a biophysical model of the rate-limiting processes underlying the fitness advantage conferred on cancer cells by driver gene mutations. Focusing on TP53, the most mutated gene in cancer1, we present an inference of mutant p53 concentration and demonstrate that TP53 hotspot mutations optimally solve an evolutionary trade-off between oncogenic potential and neoantigen immunogenicity. Our model anticipates patient survival in The Cancer Genome Atlas and patients with lung cancer treated with immunotherapy as well as the age of tumour onset in germline carriers of TP53 variants. The predicted differential immunogenicity between hotspot mutations was validated experimentally in patients with cancer and in a unique large dataset of healthy individuals. Our data indicate that immune selective pressure on TP53 mutations has a smaller role in non-cancerous lesions than in tumours, suggesting that targeted immunotherapy may offer an early prophylactic opportunity for the former. Determining the relative contribution of immunogenicity and oncogenic function to the selective advantage of hotspot mutations thus has important implications for both precision immunotherapies and our understanding of tumour evolution.

Single-cell genomic variation induced by mutational processes in cancer.

How cell-to-cell copy number alterations that underpin genomic instability1 in human cancers drive genomic and phenotypic variation, and consequently the evolution of cancer2, remains understudied. Here, by applying scaled single-cell whole-genome sequencing3 to wild-type, TP53-deficient and TP53-deficient;BRCA1-deficient or TP53-deficient;BRCA2-deficient mammary epithelial cells (13,818 genomes), and to primary triple-negative breast cancer (TNBC) and high-grade serous ovarian cancer (HGSC) cells (22,057 genomes), we identify three distinct 'foreground' mutational patterns that are defined by cell-to-cell structural variation. Cell- and clone-specific high-level amplifications, parallel haplotype-specific copy number alterations and copy number segment length variation (serrate structural variations) had measurable phenotypic and evolutionary consequences. In TNBC and HGSC, clone-specific high-level amplifications in known oncogenes were highly prevalent in tumours bearing fold-back inversions, relative to tumours with homologous recombination deficiency, and were associated with increased clone-to-clone phenotypic variation. Parallel haplotype-specific alterations were also commonly observed, leading to phylogenetic evolutionary diversity and clone-specific mono-allelic expression. Serrate variants were increased in tumours with fold-back inversions and were highly correlated with increased genomic diversity of cellular populations. Together, our findings show that cell-to-cell structural variation contributes to the origins of phenotypic and evolutionary diversity in TNBC and HGSC, and provide insight into the genomic and mutational states of individual cancer cells.

TOX is a critical regulator of tumour-specific T cell differentiation.

Tumour-specific CD8 T cell dysfunction is a differentiation state that is distinct from the functional effector or memory T cell states1-6. Here we identify the nuclear factor TOX as a crucial regulator of the differentiation of tumour-specific T (TST) cells. We show that TOX is highly expressed in dysfunctional TST cells from tumours and in exhausted T cells during chronic viral infection. Expression of TOX is driven by chronic T cell receptor stimulation and NFAT activation. Ectopic expression of TOX in effector T cells in vitro induced a transcriptional program associated with T cell exhaustion. Conversely, deletion of Tox in TST cells in tumours abrogated the exhaustion program: Tox-deleted TST cells did not upregulate genes for inhibitory receptors (such as Pdcd1, Entpd1, Havcr2, Cd244 and Tigit), the chromatin of which remained largely inaccessible, and retained high expression of transcription factors such as TCF-1. Despite their normal, 'non-exhausted' immunophenotype, Tox-deleted TST cells remained dysfunctional, which suggests that the regulation of expression of inhibitory receptors is uncoupled from the loss of effector function. Notably, although Tox-deleted CD8 T cells differentiated normally to effector and memory states in response to acute infection, Tox-deleted TST cells failed to persist in tumours. We hypothesize that the TOX-induced exhaustion program serves to prevent the overstimulation of T cells and activation-induced cell death in settings of chronic antigen stimulation such as cancer.

Senescence induction dictates response to chemo- and immunotherapy in preclinical models of ovarian cancer.

High-grade serous ovarian carcinoma (HGSOC) is a cancer with dismal prognosis due to the limited effectiveness of existing chemo- and immunotherapies. To elucidate mechanisms mediating sensitivity or resistance to these therapies, we developed a fast and flexible autochthonous mouse model based on somatic introduction of HGSOC-associated genetic alterations into the ovary of immunocompetent mice using tissue electroporation. Tumors arising in these mice recapitulate the metastatic patterns and histological, molecular, and treatment response features of the human disease. By leveraging these models, we show that the ability to undergo senescence underlies the clinically observed increase in sensitivity of homologous recombination (HR)-deficient HGSOC tumors to platinum-based chemotherapy. Further, cGas/STING-mediated activation of a restricted senescence-associated secretory phenotype (SASP) was sufficient to induce immune infiltration and sensitize HR-deficient tumors to immune checkpoint blockade. In sum, our study identifies senescence propensity as a predictor of therapy response and defines a limited SASP profile that appears sufficient to confer added vulnerability to concurrent immunotherapy and, more broadly, provides a blueprint for the implementation of electroporation-based mouse models to reveal mechanisms of oncogenesis and therapy response in HGSOC.

Pathogenic germline variants in non-BRCA1/2 homologous recombination genes in ovarian cancer: Analysis of tumor phenotype and survival.

OBJECTIVE: To define molecular features of ovarian cancer (OC) with germline pathogenic variants (PVs) in non-BRCA homologous recombination (HR) genes and analyze survival compared to BRCA1/2 and wildtype (WT) OC. METHODS: We included patients with OC undergoing tumor-normal sequencing (MSK-IMPACT) from 07/01/2015-12/31/2020, including germline assessment of BRCA1/2 and other HR genes ATM, BARD1, BRIP1, FANCA, FANCC, NBN, PALB2, RAD50, RAD51B, RAD51C, and RAD51D. Biallelic inactivation was assessed within tumors. Progression-free (PFS) and overall survival (OS) were calculated from pathologic diagnosis using the Kaplan-Meier method with left truncation. Whole-exome sequencing (WES) was performed in a subset. RESULTS: Of 882 patients with OC, 56 (6.3%) had germline PVs in non-BRCA HR genes; 95 (11%) had BRCA1-associated OC (58 germline, 37 somatic); and 59 (6.7%) had BRCA2-associated OC (40 germline, 19 somatic). High rates of biallelic alterations were observed among germline PVs in BRIP1 (11/13), PALB2 (3/4), RAD51B (3/4), RAD51C (3/4), and RAD51D (8/10). In cases with WES (27/35), there was higher tumor mutational burden (TMB; median 2.5 [1.1-6.0] vs. 1.2 mut/Mb [0.6-2.6]) and enrichment of HR-deficient (HRD) mutational signatures in tumors associated with germline PALB2 and RAD51B/C/D compared with BRIP1 PVs (p < 0.01). Other features of HRD, including telomeric-allelic imbalance (TAI) and large-scale state transitions (LSTs), were similar. Although there was heterogeneity in PFS/OS by gene group, only BRCA1/2-associated OC had improved survival compared to WT OC (p < 0.01). CONCLUSIONS: OCs associated with germline PVs in non-BRCA HR genes represent a heterogenous group, with PALB2 and RAD51B/C/D associated with an HRD phenotype.

IRE1α-XBP1 controls T cell function in ovarian cancer by regulating mitochondrial activity.

Tumours evade immune control by creating hostile microenvironments that perturb T cell metabolism and effector function1-4. However, it remains unclear how intra-tumoral T cells integrate and interpret metabolic stress signals. Here we report that ovarian cancer-an aggressive malignancy that is refractory to standard treatments and current immunotherapies5-8-induces endoplasmic reticulum stress and activates the IRE1α-XBP1 arm of the unfolded protein response9,10 in T cells to control their mitochondrial respiration and anti-tumour function. In T cells isolated from specimens collected from patients with ovarian cancer, upregulation of XBP1 was associated with decreased infiltration of T cells into tumours and with reduced IFNG mRNA expression. Malignant ascites fluid obtained from patients with ovarian cancer inhibited glucose uptake and caused N-linked protein glycosylation defects in T cells, which triggered IRE1α-XBP1 activation that suppressed mitochondrial activity and IFNγ production. Mechanistically, induction of XBP1 regulated the abundance of glutamine carriers and thus limited the influx of glutamine that is necessary to sustain mitochondrial respiration in T cells under glucose-deprived conditions. Restoring N-linked protein glycosylation, abrogating IRE1α-XBP1 activation or enforcing expression of glutamine transporters enhanced mitochondrial respiration in human T cells exposed to ovarian cancer ascites. XBP1-deficient T cells in the metastatic ovarian cancer milieu exhibited global transcriptional reprogramming and improved effector capacity. Accordingly, mice that bear ovarian cancer and lack XBP1 selectively in T cells demonstrate superior anti-tumour immunity, delayed malignant progression and increased overall survival. Controlling endoplasmic reticulum stress or targeting IRE1α-XBP1 signalling may help to restore the metabolic fitness and anti-tumour capacity of T cells in cancer hosts.

Prognosis of isolated tumor cells and use of molecular classification in early stage endometrioid endometrial cancer.

OBJECTIVE: We assessed the prognosis and molecular subtypes of early stage endometrioid endometrial cancer with isolated tumor cells within sentinel lymph nodes (SLNs) compared with node negative disease. METHODS: Patients diagnosed with stage IA, IB, or II endometrioid endometrial cancer and primary surgical management were identified from January 1, 2007 to December 31, 2019. All SLNs underwent ultrastaging according to the institutional protocol. Patients with cytokeratin positive cells, micrometastases, and macrometastases were excluded. Clinical, pathology, and molecular subtype data were reviewed. RESULTS: Overall, 1214 patients with early stage endometrioid endometrial cancer met the inclusion criteria, of whom 1089 (90%) had node negative disease and 125 (10%) had isolated tumor cells. Compared with node negative disease, the presence of isolated tumor cells had a greater association with deep myometrial invasion, lymphovascular space invasion, receipt of adjuvant therapy, and adjuvant chemotherapy with or without radiation (p<0.01). There was no significant difference in survival rates between patients with isolated tumor cells and node negative disease (3 year progression free survival rate 94% vs 91%, respectively, p=0.21; 3 year overall survival rate 98% vs 96%, respectively, p=0.45). Progression free survival did not significantly differ among patients with isolated tumor cells who received no adjuvant therapy or chemotherapy with or without radiation (p=0.31). There was no difference in the distribution of molecular subtypes between patients with isolated tumor cells (n=28) and node negative disease (n=194; p=0.26). Three year overall survival rates differed significantly when stratifying the entire cohort by molecular subtype (p=0.04). CONCLUSIONS: Patients with isolated tumor cells demonstrated less favorable uterine pathologic features and received more adjuvant treatment with similar survival compared with patients with nodenegative disease. Among the available data, molecular classification did not have a significant association with the presence of isolated tumor cells, although copy number-high status was a poor prognostic indicator in early stage endometrioid endometrial cancer.

Procedural interventions for oligoprogression during treatment with immune checkpoint blockade in gynecologic malignancies: a case series.

OBJECTIVE: To evaluate the feasibility and outcomes of performing procedural interventions, defined as surgical resection, tumor ablation, or targeted radiation therapy, for oligoprogressive disease among patients with gynecologic malignancies who are treated with immune checkpoint blockade. METHODS: Patients with gynecologic cancers treated with immune checkpoint blockade between January 2013 and October 2021 who underwent procedural interventions including surgical resection, interventional radiology ablation, or radiation therapy for oligoprogressive disease were identified. Procedures performed before immune checkpoint therapy initiation or ≥6 months after therapy completion were excluded. Long immunotherapy duration prior to intervention was defined as ≥6 months. Progression-free survival and overall survival were calculated from procedure date until disease progression or death, respectively. RESULTS: During the study period, 886 patients met inclusion criteria and received immune checkpoint blockade therapy. Of these, 34 patients underwent procedural interventions for oligoprogressive disease; 7 underwent surgical resection, 3 underwent interventional radiology ablation, and 24 underwent radiation therapy interventions. Primary disease sites included uterus (71%), ovary (24%), and cervix (6%). Sites of oligoprogression included abdomen/pelvis (26%), bone (21%), lung (18%), distant lymph node (18%), brain (9%), liver (6%), and vagina (3%). Most tumors (76%) did not exhibit microsatellite instability or mismatch repair deficiency. Approximately half (53%) of the patients had long immune checkpoint therapy duration prior to intervention. Median progression-free survival following the procedure was 5.3 months (95% CI, 3.1-9.9), and median overall survival was 21.7 months (95% CI, 14.9-not estimable). Long versus short immune checkpoint therapy duration prior to procedure and length of immune checkpoint therapy had no effect on progression-free or overall survival. CONCLUSIONS: Procedural interventions for patients with oligoprogression on immune checkpoint blockade therapy are feasible and demonstrate favorable outcomes. With expanding use of immune checkpoint therapy, it is important to investigate combined modalities to maximize therapeutic benefit for patients with gynecologic cancers.

Impact of immune infiltration signatures on prognosis in endometrial carcinoma is dependent on the underlying molecular subtype.

OBJECTIVES: Increased numbers of tumor infiltrating lymphocytes (TIL) in endometrial cancer (EC) are associated with improved survival, but it is unclear how this prognostic significance relates to the underlying EC molecular subtype. In this explorative hypothesis-generating study, we sought to define the immune signatures associated with the molecular subtypes of EC (i.e., POLE-mutated, microsatellite unstable (MSI-high), copy number (CN)-low, and CN-high) and to determine their correlation with patient outcomes. METHODS: RNA-sequencing and molecular subtype data of 232 primary ECs were obtained from The Cancer Genome Atlas. Deconvolution of bulk gene expression data was performed using single sample Gene Set Enrichment Analysis (ssGSEA) and Cell type Identification By Estimating Relative Subsets Of known RNA Transcripts (CIBERSORT). The association of the resultant immune signatures with overall survival was determined across molecular subtypes. RESULTS: Statistically significant differences in enrichment were identified in 16/30 and 6/23 immune gene sets by ssGSEA and CIBERSORT, respectively. Signature of CD8+ cells in ECs of CN-high molecular subtype was associated with improved overall survival by ssGSEA (p = 0.0108), while CD8 signatures did not appear to be prognostic in MSI-high (p = 0.74) or CN-low EC molecular subtypes (p = 0.793). Of all molecular subtypes, CN-high ECs exhibited the lowest levels of CD8+ T cell infiltration. Consistent with antigen-induced T cell activation and exhaustion, enrichment for immunomodulatory receptors was predominantly observed in ECs of MSI-high and POLE-mutated molecular subtypes. CONCLUSIONS: Deconvolution of bulk gene expression data can be used to identify populations of immune infiltrated endometrial cancers with improved survival. These data support the existence of unique mechanisms of immune resistance within molecular subgroups of the disease.

Durvalumab with or without tremelimumab in patients with persistent or recurrent endometrial cancer or endometrial carcinosarcoma: A randomized open-label phase 2 study.

INTRODUCTION: Our understanding of the biologic heterogeneity of endometrial cancer has improved, but which patients benefit from single-agent versus combination immune checkpoint blockade remains unclear. METHODS: We conducted a single-center, randomized, open-label, phase 2 study of durvalumab 1500 mg (Arm 1) versus durvalumab 1500 mg plus tremelimumab 75 mg every 4 weeks (Arm 2) in patients with endometrial carcinoma. The primary endpoints were overall response rate (ORR) and progression-free survival (PFS) at 24 weeks. Patients were stratified by mismatch repair (MMR) status and carcinosarcoma histology. Using a Simon two-stage minimax design, we determined 40 patients per arm would provide 90% power and Type 1 error of 10%. RESULTS: Eighty-two patients were enrolled; 77 were evaluable for toxicity (Arm 1: 38, Arm 2: 39) and 75 evaluable for efficacy (Arm 1: 37, Arm 2: 38). Patient were stratified by MMR status (Arm 1: 5, Arm 2: 4 were MMR-deficient). The ORR in Arm 1 was 10.8% (one-sided 90% CI: 4.8-100%); the ORR in Arm 2 was 5.3% (one-sided 90% CI: 1.4-100%). Since the primary endpoint of ORR was not met, 24-week PFS was not compared to historical controls per protocol specification. No new safety signals were identified. CONCLUSIONS: In these patients with predominantly MMR-proficient endometrial cancer, there was limited response with single-agent and combined immune checkpoint blockade. The pre-specified efficacy thresholds were not met for further evaluation. A deeper understanding of potential mechanisms of resistance to immunotherapy in MMR-proficient endometrial cancer is needed for the development of novel therapeutic approaches.

A phase 2 study of dasatinib in recurrent clear cell carcinoma of the ovary, fallopian tube, peritoneum or endometrium: NRG oncology/gynecologic oncology group study 0283.

OBJECTIVE: Gynecologic cancers are traditionally managed according to their presumed site of origin, without regard to the underlying histologic subtype. Clear cell histology is associated with chemotherapy refractoriness and poor survival. Mutations in SWI/SNF chromatin remodeling complex member ARID1A, which encodes for BAF250a protein, are common in clear cell and endometriosis-associated endometrioid carcinomas. High-throughput cell-based drug screening predicted activity of dasatinib, a tyrosine kinase inhibitor, in ARID1A-mutant clear cell carcinoma. METHODS: We conducted a phase 2 clinical trial of dasatinib 140 mg once daily by mouth in patients with recurrent or persistent ovarian and endometrial clear cell carcinoma. Patients with measurable disease were enrolled and then assigned to biomarker-defined populations based on BAF250a immunohistochemistry. The translational endpoints included broad next-generation sequencing to assess concordance of protein expression and treatment outcomes. RESULTS: Twenty-eight patients, 15 of whom had tumors with retained BAF250a and 13 with loss of BAF250a were evaluable for treatment response and safety. The most common grade 3 adverse events were anemia, fatigue, dyspnea, hyponatremia, pleural effusion, and vomiting. One patient had a partial response, eight (28%) had stable disease, and 15 (53.6%) had disease progression. Twenty-three patients had next-generation sequencing results; 13 had a pathogenic ARID1A alteration. PIK3CA mutations were more prevalent in ARID1A-mutant tumors, while TP53 mutations were more prevalent in ARID1A wild-type tumors. CONCLUSIONS: Dasatinib was not an effective single-agent treatment for recurrent or persistent ovarian and endometrial clear cell carcinoma. Studies are urgently needed for this rare gynecologic subtype.

Recurrent WWTR1 S89W mutations and Hippo pathway deregulation in clear cell carcinomas of the cervix.

Clear cell carcinoma (CCC) of the cervix (cCCC) is a rare and aggressive type of human papillomavirus (HPV)-negative cervical cancer with limited effective treatment options for recurrent or metastatic disease. Historically, CCCs of the lower genital tract were associated with in utero diethylstilbestrol exposure; however, the genetic landscape of sporadic cCCCs remains unknown. Here we sought to define the molecular underpinning of cCCCs. Using a combination of whole-exome, targeted capture, and RNA-sequencing, we identified pathogenic genetic alterations in the Hippo signaling pathway in 50% (10/20) of cCCCs, including recurrent WWTR1 S89W somatic mutations in 40% (4/10) of the cases harboring mutations in the Hippo pathway. Irrespective of the presence or absence of Hippo pathway genetic alterations, however, all primary cCCCs analyzed in this study (n = 20) harbored features of Hippo pathway deregulation at the transcriptomic and protein levels. In vitro functional analysis revealed that expression of the WWTR1 S89W mutation leads to reduced binding of TAZ to 14-3-3, promoting constitutive nuclear translocation of TAZ and Hippo pathway repression. WWTR1 S89W expression was found to lead to acquisition of oncogenic behavior, including increased proliferation, migration, and colony formation in vitro as well as increased tumorigenesis in vivo, which could be reversed by targeted inhibition of the TAZ/YAP1 complex with verteporfin. Finally, xenografts expressing WWTR1 S89W displayed a shift in tumor phenotype, becoming more infiltrative as well as less differentiated, and were found to be composed of cells with conspicuous cytoplasmic clearing as compared to controls. Our results demonstrate that Hippo pathway alterations are likely drivers of cCCCs and likely contribute to the clear cell phenotype. Therapies targeting this pathway may constitute a new class of treatment for these rare, aggressive tumors. © 2022 The Pathological Society of Great Britain and Ireland.

Hyperthermic intraperitoneal chemotherapy (HIPEC) with carboplatin induces distinct transcriptomic changes in ovarian tumor and normal tissues.

OBJECTIVE: To determine the effect of hyperthermic intraperitoneal chemotherapy (HIPEC) with carboplatin on the transcriptomic profiles of normal and ovarian cancer (OC) tissues. METHODS: Normal and tumor samples from four OCs were prospectively collected pre- and immediately post-HIPEC treatment and subjected to RNA-sequencing. Differential gene expression, gene ontology enrichment and pathway analyses were performed. Heat shock protein and immune-response protein expression was assessed using protein arrays and western blotting. RESULTS: RNA-sequencing revealed 4231 and 322 genes significantly differentially expressed between pre- and post-treatment normal and OC tissues, respectively (both adjusted p-value <0.05). Gene enrichment analyses demonstrated that the most significantly upregulated genes in normal tissues played a role in immune as well as heat shock response (both adjusted p < 0.001). In contrast, HIPEC induced an increased expression of primarily heat shock response and protein folding-related genes in tumor tissues (both adjusted p < 0.001). HIPEC-induced heat shock protein (HSP) expression changes, including in HSP90, HSP40, HSP60, and HSP70, were also observed at the protein level in both normal and tumor tissues. CONCLUSIONS: HIPEC with carboplatin resulted in an upregulation of heat shock-related genes in both normal and tumor tissue, with an additional immune response gene induction in normal and protein folding in tumor tissue. The findings of our exploratory study provide evidence to suggest that HIPEC administration may suffice to induce gene expression changes in residual tumor cells and raises a biological basis for the consideration of combinatorial treatments with HSP inhibitors.

Phase II study of enzalutamide in androgen receptor positive, recurrent, high- and low-grade serous ovarian cancer.

OBJECTIVES: We sought to determine the safety and efficacy of the oral androgen receptor antagonist enzalutamide in patients with previously treated, recurrent, AR-positive (AR+) ovarian cancer. METHODS: This was a single-institution phase II study of patients with AR+ ovarian cancer with measurable disease with 1-3 prior lines of chemotherapy; patients were screened for enrollment from 11/2013-7/2018. Following consent, archival tissue was evaluated for AR+. Enrolled patients received daily enzalutamide 160 mg until progression of disease or treatment discontinuation. Adverse events were graded by CTCAE v4.0. Co-primary endpoints were 6-month progression-free survival (PFS6) and overall response rate (ORR) by RECIST 1.1 criteria. RESULTS: During the study period, 160 patients were screened and 59 (45 high-grade serous [HGS] and 14 low-grade serous [LGS]) consented to treatment on study. There was 1 confirmed and 1 unconfirmed partial response. The ORR was 1.7% (90% CI: 0.2-100%). The overall PFS6 rate (as binary) was 22% (90% CI: 15.1-100%). The 6-month PFS rate (as time to event) was 19.8% for HGS patients (90% CI: 12.7-100%) and 38.5% (90% CI: 21.7%-100%) for LGS patients. Grade 3 toxicities occurred in 6 patients (one toxicity (Grade 3 rash) was considered a dose-limiting toxicity). One patient died of cardiac arrest after 42 days on treatment of a cardiac arrest not attributed to study drug. CONCLUSIONS: The study met its primary endpoint, with a PFS6 rate of 22% (n = 13); however, the overall response rate was low. Enzalutamide was well tolerated and may be a potential treatment option in select patients.

Gastric-type adenocarcinoma of the cervix: Clinical outcomes and genomic drivers.

OBJECTIVES: Gastric-type endocervical adenocarcinoma (GEA) is a rare form of cervical cancer not associated with human papilloma virus (HPV) infection. We summarize our experience with GEA at a large cancer center. METHODS: Clinical and demographic information on all patients diagnosed with GEA between June 1, 2002 and July 1, 2019 was obtained retrospectively from clinical charts. Kaplan-Meier survival analysis was performed to describe progression-free survival (PFS) and overall survival (OS). Tumors from a subset of patients underwent next generation sequencing (NGS) analysis. RESULTS: A total of 70 women with GEA were identified, including 43 who received initial treatment at our institution: of these 4 (9%) underwent surgery alone, 15 (35%) underwent surgery followed by adjuvant therapy, 10 (23%) were treated with definitive concurrent chemoradiation (CCRT), 7 (16%) with chemotherapy alone, and 3 (7%) with neoadjuvant CCRT and hysterectomy with or without chemotherapy. One-third (n = 14) of patients experienced disease progression, of whom 86% (n = 12) had prior CCRT. The median PFS and OS for patients with stage I GEA were 107 months (95% CI 14.8-199.2 months) and 111 months (95% CI 17-205.1 months) respectively, compared to 17 months (95% CI 5.6-28.4 months) and 33 months (95% CI 28.2-37.8 months) for patients with stages II-IV, respectively. On NGS, 4 patients (14%) had ERBB2 alterations, including 2 patients who received trastuzumab. CONCLUSIONS: GEA is an aggressive form of cervical cancer with poor PFS and OS when diagnosed at stage II or later. Further investigation is needed to identify the optimal management approach for this rare subtype.

Treatment of ovarian clear cell carcinoma with immune checkpoint blockade: a case series.

BACKGROUND: Although immune checkpoint blockade has demonstrated limited effectiveness against ovarian cancer, subset analyses from completed trials suggest possible superior efficacy in the clear cell carcinoma subtype. OBJECTIVE: To describe the outcomes of patients with ovarian clear cell carcinoma treated with immune checkpoint blockade. METHODS: This was a single-institution, retrospective case series of patients with ovarian clear cell carcinoma treated with a programmed cell death protein 1 (PD-1) or programmed death-ligand 1 (PD-L1) inhibitor with or without concomitant cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) inhibition between January 2016 and June 2021. Demographic variables, tumor microenvironment, molecular data, and clinical outcomes were examined. Time to treatment failure was defined as the number of days between start of treatment and next line of treatment or death. RESULTS: A total of 16 eligible patients were analyzed. The median treatment duration was 56 days (range 14-574); median time to treatment failure was 99 days (range 27-1568). The reason for discontinuation was disease progression in 88% of cases. Four patients (25%) experienced durable clinical benefit (time to treatment failure ≥180 days). One patient was treated twice with combined immune checkpoint blockade and experienced a complete response each time. All 12 patients who underwent clinical tumor-normal molecular profiling had microsatellite-stable disease, and all but one had low tumor mutation burden. Multiplex immunofluorescence analysis available from pre-treatment biopsies of two patients with clinical benefit demonstrated abundant tumor-infiltrating lymphocytes expressing PD-1. CONCLUSION: Our study suggests a potential role for immune checkpoint blockade in patients with clear cell carcinoma of the ovary. Identification of genetic and microenvironmental biomarkers predictive of response will be key to guide therapy.