Image-based multiplex immune profiling of cancer tissues: translational implications. A report of the International Immuno-oncology Biomarker Working Group on Breast Cancer

Recent advances in the field of immuno-oncology have brought transformative changes in the management of cancer patients. The immune profile of tumours has been found to have key value in predicting disease prognosis and treatment response in various cancers. Multiplex immunohistochemistry and immunofluorescence have emerged as potent tools for the simultaneous detection of multiple protein biomarkers in a single tissue section, thereby expanding opportunities for molecular and immune profiling while preserving tissue samples. By establishing the phenotype of individual tumour cells when distributed within a mixed cell population, the identification of clinically relevant biomarkers with high-throughput multiplex immunophenotyping of tumour samples has great potential to guide appropriate treatment choices. Moreover, the emergence of novel multi-marker imaging approaches can now provide unprecedented insights into the tumour microenvironment, including the potential interplay between various cell types. However, there are significant challenges to widespread integration of these technologies in daily research and clinical practice. This review addresses the challenges and potential solutions within a structured framework of action from a regulatory and clinical trial perspective. New developments within the field of immunophenotyping using multiplexed tissue imaging platforms and associated digital pathology are also described, with a specific focus on translational implications across different subtypes of cancer. © 2024 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

HIV viral protein R induces loss of DCT1-type renal tubules

Hyponatremia and salt wasting is a common occurance in patients with HIV/AIDS, however, the understanding of its contributing factors is limited. HIV viral protein R (Vpr) contributes to HIV-associated nephropathy. To investigate the effects of Vpr on the expression level of the Slc12a3 gene, encoding the Na-Cl cotransporter, which is responsible for sodium reabsorption in distal nephron segments, we performed single-nucleus RNA sequencing of kidney cortices from three wild-type (WT) and three Vpr-transgenic (Vpr Tg) mice. The results showed that the percentage of distal convoluted tubule (DCT) cells was significantly lower in Vpr Tg mice compared with WT mice (P < 0.05), and that in Vpr Tg mice, Slc12a3 expression was not different in DCT cell cluster. The Pvalb + DCT1 subcluster had fewer cells in Vpr Tg mice compared with WT (P < 0.01). Immunohistochemistry demonstrated fewer Slc12a3 + Pvalb + DCT1 segments in Vpr Tg mice. Differential gene expression analysis comparing Vpr Tg and WT in the DCT cluster showed Ier3 , an inhibitor of apoptosis, to be the most downregulated gene. These observations demonstrate that the salt-wasting effect of Vpr in Vpr Tg mice is mediated by loss of Slc12a3 + Pvalb + DCT1 segments via apoptosis dysregulation.

Pitfalls in machine learning-based assessment of tumor-infiltrating lymphocytes in breast cancer: A report of the International Immuno-Oncology Biomarker Working Group on Breast Cancer

The clinical significance of the tumor-immune interaction in breast cancer is now established, and tumor-infiltrating lymphocytes (TILs) have emerged as predictive and prognostic biomarkers for patients with triple-negative (estrogen receptor, progesterone receptor, and HER2-negative) breast cancer and HER2-positive breast cancer. How computational assessments of TILs might complement manual TIL assessment in trial and daily practices is currently debated. Recent efforts to use machine learning (ML) to automatically evaluate TILs have shown promising results. We review state-of-the-art approaches and identify pitfalls and challenges of automated TIL evaluation by studying the root cause of ML discordances in comparison to manual TIL quantification. We categorize our findings into four main topics: (1) technical slide issues, (2) ML and image analysis aspects, (3) data challenges, and (4) validation issues. The main reason for discordant assessments is the inclusion of false-positive areas or cells identified by performance on certain tissue patterns or design choices in the computational implementation. To aid the adoption of ML for TIL assessment, we provide an in-depth discussion of ML and image analysis, including validation issues that need to be considered before reliable computational reporting of TILs can be incorporated into the trial and routine clinical management of patients with triple-negative breast cancer. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Spatial analyses of immune cell infiltration in cancer: current methods and future directions: A report of the International Immuno-Oncology Biomarker Working Group on Breast Cancer

Modern histologic imaging platforms coupled with machine learning methods have provided new opportunities to map the spatial distribution of immune cells in the tumor microenvironment. However, there exists no standardized method for describing or analyzing spatial immune cell data, and most reported spatial analyses are rudimentary. In this review, we provide an overview of two approaches for reporting and analyzing spatial data (raster versus vector-based). We then provide a compendium of spatial immune cell metrics that have been reported in the literature, summarizing prognostic associations in the context of a variety of cancers. We conclude by discussing two well-described clinical biomarkers, the breast cancer stromal tumor infiltrating lymphocytes score and the colon cancer Immunoscore, and describe investigative opportunities to improve clinical utility of these spatial biomarkers. © 2023 The Pathological Society of Great Britain and Ireland.

HIV-1 Vpr suppresses expression of the thiazide-sensitive sodium chloride co-transporter in the distal convoluted tubule

HIV-associated nephropathy (HIVAN) impairs functions of both glomeruli and tubules. Attention has been previously focused on the HIVAN glomerulopathy. Tubular injury has drawn increased attention because sodium wasting is common in hospitalized HIV/AIDS patients. We used viral protein R (Vpr)-transgenic mice to investigate the mechanisms whereby Vpr contributes to urinary sodium wasting. In phosphoenolpyruvate carboxykinase promoter-driven Vpr-transgenic mice, in situ hybridization showed that Vpr mRNA was expressed in all nephron segments, including the distal convoluted tubule. Vpr-transgenic mice, compared with wild-type littermates, markedly increased urinary sodium excretion, despite similar plasma renin activity and aldosterone levels. Kidneys from Vpr-transgenic mice also markedly reduced protein abundance of the Na⁺-Cl^- cotransporter (NCC), while mineralocorticoid receptor (MR) protein expression level was unchanged. In African green monkey kidney cells, Vpr abrogated the aldosterone-mediated stimulation of MR transcriptional activity. Gene expression of Slc12a3 (NCC) in Vpr-transgenic mice was significantly lower compared with wild-type mice, assessed by both qRT-PCR and RNAScope in situ hybridization analysis. Chromatin immunoprecipitation assays identified multiple MR response elements (MRE), located from 5 kb upstream of the transcription start site and extending to the third exon of the SLC12A3 gene. Mutation of MRE and SP1 sites in the SLC12A3 promoter region abrogated the transcriptional responses to aldosterone and Vpr, indicating that functional MRE and SP1 are required for the SLC12A3 gene suppression in response to Vpr. Thus, Vpr attenuates MR transcriptional activity and inhibits Slc12a3 transcription in the distal convoluted tubule and contributes to salt wasting in Vpr-transgenic mice.

Quantification of Glomerular Structural Lesions: Associations With Clinical Outcomes and Transcriptomic Profiles in Nephrotic Syndrome

RATIONALE & OBJECTIVE

The current classification system for focal segmental glomerulosclerosis (FSGS) and minimal change disease (MCD) does not fully capture the complex structural changes in kidney biopsies nor the clinical and molecular heterogeneity of these diseases.

STUDY DESIGN

Prospective observational cohort study.

SETTING & PARTICIPANTS

221 MCD and FSGS patients enrolled in the Nephrotic Syndrome Study Network (NEPTUNE).

EXPOSURE

The NEPTUNE Digital Pathology Scoring System (NDPSS) was applied to generate scores for 37 glomerular descriptors.

OUTCOME

Time from biopsy to complete proteinuria remission, time from biopsy to kidney disease progression (40% estimated glomerular filtration rate [eGFR] decline or kidney failure), and eGFR over time.

ANALYTICAL APPROACH

Cluster analysis was used to group patients with similar morphologic characteristics. Glomerular descriptors and patient clusters were assessed for associations with outcomes using adjusted Cox models and linear mixed models. Messenger RNA from glomerular tissue was used to assess differentially expressed genes between clusters and identify genes associated with individual descriptors driving cluster membership.

RESULTS

Three clusters were identified: X (n = 56), Y (n = 68), and Z (n = 97). Clusters Y and Z had higher probabilities of proteinuria remission (HRs of 1.95 [95% CI, 0.99-3.85] and 3.29 [95% CI, 1.52-7.13], respectively), lower hazards of disease progression (HRs of 0.22 [95% CI, 0.08-0.57] and 0.11 [95% CI, 0.03-0.45], respectively), and lower loss of eGFR over time compared with X. Cluster X had 1,920 genes that were differentially expressed compared with Y+Z; these reflected activation of pathways of immune response and inflammation. Six descriptors driving the clusters individually correlated with clinical outcomes and gene expression.

LIMITATIONS

Low prevalence of some descriptors and biopsy at a single time point.

CONCLUSIONS

The NDPSS allows for categorization of FSGS/MCD patients into clinically and biologically relevant subgroups, and uncovers histologic parameters associated with clinical outcomes and molecular signatures not included in current classification systems.

Progesterone receptor isoform ratio dictates antiprogestin/progestin effects on breast cancer growth and metastases: A role for NDRG1

Progesterone receptors (PR) ligands are being tested in luminal breast cancer. There are mainly two PR isoforms, PRA and PRB, and their ratio (PRA/PRB) may be predictive of antiprogestin response. Our aim was to investigate: the impact of the PR isoform ratio on metastatic behavior, the PR isoform ratio in paired primary tumors and lymph node metastases (LNM) and, the effect of antiprogestin/progestins on metastatic growth. Using murine and human metastatic models, we demonstrated that tumors with PRB > PRA (PRB-H) have a higher proliferation index but less metastatic ability than those with PRA > PRB (PRA-H). Antiprogestins and progestins inhibited metastatic burden in PRA-H and PRB-H models, respectively. In breast cancer samples, LNM retained the same PRA/PRB ratio as their matched primary tumors. Moreover, PRA-H LNM expressed higher total PR levels than the primary tumors. The expression of NDRG1, a metastasis suppressor protein, was higher in PRB-H compared with PRA-H tumors and was inversely regulated by antiprogestins/progestins. The binding of the corepressor SMRT at the progesterone responsive elements of the NDRG1 regulatory sequences, together with PRA, impeded its expression in PRA-H cells. Antiprogestins modulate the interplay between SMRT and AIB1 recruitment in PRA-H or PRB-H contexts regulating NDRG1 expression and thus, metastasis. In conclusion, we provide a mechanistic interpretation to explain the differential role of PR isoforms in metastatic growth and highlight the therapeutic benefit of using antiprogestins in PRA-H tumors. The therapeutic effect of progestins in PRB-H tumors is suggested. This article is protected by copyright. All rights reserved.

Mammary collagen architecture and its association with mammographic density and lesion severity among women undergoing image-guided breast biopsy

Background

Elevated mammographic breast density is a strong breast cancer risk factor with poorly understood etiology. Increased deposition of collagen, one of the main fibrous proteins present in breast stroma, has been associated with increased mammographic density. Collagen fiber architecture has been linked to poor outcomes in breast cancer. However, relationships of quantitative collagen fiber features assessed in diagnostic biopsies with mammographic density and lesion severity are not well-established.

Methods

Clinically indicated breast biopsies from 65 in situ or invasive breast cancer cases and 73 frequency matched-controls with a benign biopsy result were used to measure collagen fiber features (length, straightness, width, alignment, orientation and density (fibers/µm²)) using second harmonic generation microscopy in up to three regions of interest (ROIs) per biopsy: normal, benign breast disease, and cancer. Local and global mammographic density volumes were quantified in the ipsilateral breast in pre-biopsy full-field digital mammograms. Associations of fibrillar collagen features with mammographic density and severity of biopsy diagnosis were evaluated using generalized estimating equation models with an independent correlation structure to account for multiple ROIs within each biopsy section.

Results

Collagen fiber density was positively associated with the proportion of stroma on the biopsy slide (p < 0.001) and with local percent mammographic density volume at both the biopsy target (p = 0.035) and within a 2 mm perilesional ring (p = 0.02), but not with global mammographic density measures. As severity of the breast biopsy diagnosis increased at the ROI level, collagen fibers tended to be less dense, shorter, straighter, thinner, and more aligned with one another (p < 0.05).

Conclusions

Collagen fiber density was positively associated with local, but not global, mammographic density, suggesting that collagen microarchitecture may not translate into macroscopic mammographic features. However, collagen fiber features may be markers of cancer risk and/or progression among women referred for biopsy based on abnormal breast imaging.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13058-021-01482-z.

Abstract 1885: Potent tumoricidal activity of a FGFR4 CART in rhabdomyosarcoma

Despite decades of multi-module therapies, RMS remains incurable once it has metastasized, thus new therapeutic strategies are warranted. FGFR4 is a developmentally regulated cell surface receptor tyrosine kinase, overexpressed in virtually all, mutationally activated in about 10% of RMS, and directly activated by PAX3-FOXO1 fusion protein which makes it a tractable target for immunotherapy. We generated fifteen binders against FGFR4 and characterized them further as candidate molecules for immune therapy. We found that 3A11, a mouse IgG antibody, bound to FGFR4 positive cell lines. The VL and VH domain of 3A11 was cloned and made into scFvFc format (mouse Fv and Human IgG1 Fc). The chimeric form of 3A11 antibody was successfully produced in vitro and retained its FGFR4 specificity with an observed binding affinity at nanomolar range. By ELISA using the extra cellular domain of human FGFR1, FGFR2, FGFR3 or FGFR4, 3A11 scFvFc showed dose dependent binding to FGFR4 only. We then made 3A11 into a second generation CAR. Human T cells transduced with 3A11 CAR construct were found to be highly potent at inducing IFN-γ, TNF-α, IL-2 and cytotoxicity when the FGFR4-CART was co-cultured with RMS cells, but not with RMS cells with FGFR4 knocked out and FGFR4 negative cells. Our in vivo testing also found that 3A11 CART was able to eliminate RMS cells in murine xenograft metastatic models. Here we report the successful generation of binders specific to human FGFR4. FGFR4 CAR developed from 3A11 was able to kill FGFR4 positive target cells both in-vivo and in-vitro. Thus, 3A11 CAR T cells targeting FGFR4 may provide effective immune therapies for rhabdomyosarcoma and other FGFR4 expressing cancers and clinical trials are planned.

Citation Format: Adam Cheuk, Meijie Tian, Jeetendra Kumar, Peter Azorsa, Nityashree Shivaprasad, Dina Schneider, Berkley Gryder, Jun Wei, Young Song, Xinyu Wen, Sivasish Sindiri, Joon-Yong Chung, Zhongyu Zhu, Dimiter Dimitrov, Stephen Hewitt, Boro Dropulic, Rimas Orentas, Javed Khan. Potent tumoricidal activity of a FGFR4 CART in rhabdomyosarcoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1885.

POS0207 REAL-WORLD RETENTION OF JAK INHIBITORS IS LONGER THAN BDMARDS IN RHEUMATOID ARTHRITIS

Background:

Biological disease modifying anti-rheumatic drugs (bDMARDs) and Janus Kinase inhibitors (JAKi) are both recommended post conventional synthetic disease modifying anti-rheumatic drug (csDMARD) therapy failure in active rheumatoid arthritis (RA), but the data on long-term durability are limited.

Objectives:

The objective of this study is to analyze a database of patients at the Western University, Rheumatology Center who initiated a bDMARD or JAKi and compare the proportion and characteristics of patients associated with retention of a drug class.

Methods:

This was a single-center study of 215 adult RA patients (82.76 % females, age 59.8 ± 12.0 years, disease duration 15.5 ± 10.0 years; table 1) failing multiple csDMARDs prior to initiating either bDMARDs (TNF inhibitors, abatacept, rituximab, tocilizumab) or JAKi, between June 2014 (when tofacitinib was approved in Canada) and April 2020. All patients enrolled had failed traditional DMARDs, including methotrexate, hydroxychloroquine, sulfasalazine and/or leflunomide. Durability and predictors of discontinuation were analyzed by Kaplan-Meier and Cox regression analyses for all treatment trials, and for patients receiving bDMARDs/JAKi as a first line after csDMARDs failure.

Results:

In 215 patients, there were 320 treatment events (148 bDMARDs, 172 JAKi) and 142 discontinuations (53.5% bDMARDs, 46.5% JAKi). Figure 1 represents the Kaplan-Meier survival curve for time to therapy discontinuation in 215 patients receiving bDMARDs vs JAKi. The Cox proportional hazards model was significant with better retention for JAKi, with a hazard ratio (HR) for treatment discontinuation of JAKi compared with bDMARDs of 0.676 (95% CI 0.47-0.97, p=0.034), adjusted for gender, age, disease duration, and line of therapy (Table 1). Moreover, the analysis revealed better retention for both groups as first line advanced therapy compared to later lines of therapy; 57.6% of JAKi and 31.1% of bDMARDs were used as first line advanced therapy. HR for treatment discontinuation for first line vs later lines of therapy was 0.593 (95% CI 0.40-0.88, p=0.01), adjusted for drug class, gender, age, and disease duration (Table 1). The most common reasons for discontinuations were inefficacy (60%), side effects (22%), or other reasons (18%). Inefficacy (58% vs 62%, p=0.8) and side-effects (16% vs 27%, p=0.4) were equally common for bDMARDs and JAKi. Sex, age at treatment onset, and RA duration did not predict discontinuation by Cox regression analyses, and after sub-grouping into bDMARDs and JAKi.

Conclusion:

EULAR guidelines have placed bDMARDs equal to JAKi as post csDMARD failure therapy in active RA. However, this study demonstrates that JAKi has a greater durability than biologics regardless of gender, age, disease duration, and line of therapy. Therefore, JAKi may be considered as a preferable method of treatment post csDMARD failure in active RA.

Figure 1.

Kaplan-Meier survival curves for (A) time to discontinuation of therapy in all RA patients receiving bDMARDs versus JAKi; P-value represents Cox regression adjusted for gender, age, disease duration, and line of therapy (B) time to discontinuation of therapy in patients using bDMARDs/JAKi as first line of advanced therapy; P-value represents Cox regression adjusted for drug class, gender, age, and disease duration

Table 1.

Patient demographics and hazard ratios for discontinuation of bDMARDs versus JAKi by Cox regression model

CharacteristicJAKi (N=172)bDMARD (N=148)MeanAge (years)60.958.559.8Sex (% F)77.888.582.8Disease duration (years)15.315.815.5Line of advanced therapy (% first line)57.631.145.3Drug used (%)Tofacitinib: 93.5Rituximab: 26.4Etanercept: 19.6Adalimumab: 17.6Predictors of Drug DiscontinuationHR (95% CIs)P valuesCrude ModelJAKi vs bDMARDs0.60 (0.43, 0.84)0.003Adjusted modelJAKi vs bDMARDs0.68 (0.47, 0.97)0.034Male vs female0.77 (0.46, 1.31)0.342Age1.01 (0.99, 1.03)0.123RA duration0.99 (0.97, 1.01)0.500Treatment line 1 vs >10.59 (0.40, 0.88)0.010

Disclosure of Interests:

Karla Machlab: None declared, Samir M. Iskandar: None declared, Tatiana Nevskaya: None declared, Louise Vanderhoek: None declared, Jillian Bylsma: None declared, Sara Hewitt: None declared, Janet Pope Speakers bureau: AbbVie, Amgen, BMS, BI, Gilead, Galapagos, Janssen, Lilly, Medexus, Merck, Novartis, Pfizer, Sanofi, Sandoz, Consultant of: AbbVie, Amgen, BMS, BI, Celltrion, Gilead, Galapagos, Janssen, Lilly, Medexus, Merck, Novartis, Pfizer, Roche, Samsung, Sanofi, Sandoz, Teva, UCB, Grant/research support from: AbbVie, BMS, Merck, Pfizer, Roche, Seattle Genetics

Integrated Single-Cell Atlases Reveal an Oral SARS-CoV-2 Infection and Transmission Axis

Despite signs of infection, the involvement of the oral cavity in COVID-19 is poorly understood. To address this, single-cell RNA sequencing data-sets were integrated from human minor salivary glands and gingiva to identify 11 epithelial, 7 mesenchymal, and 15 immune cell clusters. Analysis of SARS-CoV-2 viral entry factor expression showed enrichment in epithelia including the ducts and acini of the salivary glands and the suprabasal cells of the mucosae. COVID-19 autopsy tissues confirmed in vivo SARS-CoV-2 infection in the salivary glands and mucosa. Saliva from SARS-CoV-2-infected individuals harbored epithelial cells exhibiting ACE2 expression and SARS-CoV-2 RNA. Matched nasopharyngeal and saliva samples found distinct viral shedding dynamics and viral burden in saliva correlated with COVID-19 symptoms including taste loss. Upon recovery, this cohort exhibited salivary antibodies against SARS-CoV-2 proteins. Collectively, the oral cavity represents a robust site for COVID-19 infection and implicates saliva in viral transmission.

Dynamics of genomic and immune responses during primary immunotherapy resistance in mismatch repair-deficient tumors

Mismatch repair-deficient (dMMR) cancers generate a substantial number of immunogenic neoantigens, rendering them sensitive to immunotherapy. Yet, there is considerable variability in responses, and roughly one-half of dMMR cancers are refractory to immunotherapy. Here we study a patient with dMMR lung cancer refractory to immunotherapy. The tumor exhibited typical dMMR molecular features, including exceptionally high frameshift insertions and deletions (indels). Despite the treatment inducing abundant intratumoral T-cell infiltrates, it failed to elicit tumor regression, pointing to the T cells lacking cytotoxic activity. A post-treatment tumor demonstrated compound heterozygous frameshift deletions located upstream of the kinase domain in the gene encoding JAK1 protein, down-regulation of JAK1 and mediators of its signal transduction, and total loss of JAK1 phosphorylation. Importantly, one of the JAK1 mutations, despite not being detected in the pretreatment tumor, was found at low variant allele frequency in the pretreatment circulating tumor DNA, suggesting clonal selection of the mutation. To our knowledge, this report provides the most detailed look yet at defective JAK1 signaling in the context of dMMR and immunotherapy resistance. Together with observations of JAK1 frameshift indels being enriched in dMMR compared with MMR-proficient tumors, our findings demonstrate the critical function of JAK1 in immunological surveillance of dMMR cancer.

Abstract A08: Development of FGFR4-specific chimeric antibody receptor (CAR) T cell and bispecific T cell engager (BiTE) for rhabdomyosarcoma (RMS) immunotherapy

Background: Despite decades of multimodule therapies, RMS remains incurable once it has metastasized; thus, new therapeutic strategies are warranted. FGFR4 is a developmentally regulated cell surface receptor tyrosine kinase, overexpressed in virtually all, mutationally activated in about 7.5% of RMS, and directly activated by PAX3-FOXO1 fusion protein, which makes it a tractable target for immunotherapy.

Material and Methods: Using monoclonal antibody technologies and a yeast display B-cell library, we generated 15 human or mouse binders specific to human FGFR4 and engineered into human scFvFc. All binders were successfully produced in vitro, and we further characterized them using FACS and ELISA for their specificity. Octet was used to measure the binding affinity against human FGFR4. For those lead hits, they were made into different formats of therapeutic including CAR and BiTE. We then performed in vitro killing assays and/or in vivo xenograft model to determine the efficacy of those therapeutics in killing RMS cells.

Results: m410 and m412 were two lead hits and scFvFcs of these two binders were successfully produced in vitro and showed FGFR4 specificity with a binding affinity at nanomolar concentration. By ELISA, these binders showed dose-dependent binding to FGFR4 protein but not to other FGFR family members. We then made m410 and m412 into CAR and BiTE format, respectively. T cells transduced with m410 CAR construct were found highly potent in inducing gamma interferon, TNF alpha, and cytotoxicity when the FGFR4-CART are cocultured with RMS cells. Our in vivo testing found them to be effective in eliminating RMS cells in murine xenograft models. When T cells were cocultured with RMS cells in the presence of m412 BiTE in vitro, potent selective antitumor effect was observed, suggesting this can be another promising strategy for RMS immunotherapy.

Conclusions: Here our data demonstrated that we had successfully generated binders specific to human FGFR4. The CAR and BiTE developed from these binders were able to kill FGFR4-positive target cells. Our data suggest that these FGFR4 CARs and FGFR4 BiTEs could provide effective immune therapies for rhabdomyosarcoma and other FGFR4-expressing cancers.

Citation Format: Adam Cheuk, Nityashree Shivaprasad, Dina Schneider, Marielle Yohe, Meijie Tan, Peter Azorsa, Ronald Sams, Silvia Pomella, Berkley Gryder, Rossella Rota, Ben Stanton, Jun Wei, Young Song, Xinyu Wen, Sivasish Sindiri, Jeetendra Kumar, Robert Hawley, Joon-Yong Chung, Doncho Zhelev, Zhongyu Zhu, Dimiter Dimitrov, Stephen Hewitt, Boro Dropulic, Rimas Orentas, Javed Khan. Development of FGFR4-specific chimeric antibody receptor (CAR) T cell and bispecific T cell engager (BiTE) for rhabdomyosarcoma (RMS) immunotherapy [abstract]. In: Proceedings of the AACR Special Conference on the Advances in Pediatric Cancer Research; 2019 Sep 17-20; Montreal, QC, Canada. Philadelphia (PA): AACR; Cancer Res 2020;80(14 Suppl):Abstract nr A08.

Evaluation of the Anti-Tumor Activity of the Humanized Monoclonal Antibody NEO-201 in Preclinical Models of Ovarian Cancer

Purpose: Despite high initial response rates with cytoreductive surgery, conventional chemotherapy and the incorporation of biologic agents, ovarian cancer patients often relapse and die from their disease. New approaches are needed to improve patient outcomes. This study was designed to evaluate the antitumor activity of NEO-201 monoclonal antibody (mAb) in preclinical models of ovarian cancer where the NEO-201 target is highly expressed.

Experimental Design: Functional analysis of NEO-201 against tumor cell lines was performed by antibody-dependent cellular cytotoxicity (ADCC) assays. Binding of NEO-201 to tumor tissues and cell lines were determined by immunohistochemistry (IHC) and flow cytometry, respectively. Further characterization of the antigen recognized by NEO-201 was performed by mass spectrometry. Ovarian cancer models were used to evaluate the anti-tumor activity of NEO-201 in vivo. NEO-201 at a concentration of 250 g/mouse was injected intraperitoneally (IP) on days 1, 4, and 8. Human PBMCs were injected IP simultaneously as effector cells.

Results: Both IHC and flow cytometry revealed that NEO-201 binds prominently to the colon, pancreatic, and mucinous ovarian cancer tissues and cell lines. Immunoprecipitation of the antigen recognized by NEO-201 was performed in human ovarian, colon, and pancreatic cancer cell lines. From these screening, carcinoembryonic antigen-related cell adhesion molecule 5 (CEACAM5) and CEACAM6 were identified as the most likely targets of NEO-201. Our results confirmed that NEO-201 binds different types of cancers; the binding is highly selective for the tumor cells without cross reactivity with the surrounding healthy tissue. Functional analysis revealed that NEO-201 mediates ADCC killing against human ovarian and colorectal carcinoma cell lines in vitro. In addition, NEO-201 inhibited tumor growth in the presence of activated human PBMCs in orthotopic mouse models of both primary and metastatic ovarian cancer. Importantly, NEO-201 prolonged survival of tumor-bearing mice.

Conclusions: These data suggested that NEO-201 has an antitumor activity against tumor cells expressing its antigen. Targeting an antigen expressed in tumors, but not in normal tissues, allows patient selection for optimal treatment. These findings strongly indicate that NEO-201 warrants clinical testing as both a novel therapeutic and diagnostic agent for treatment of ovarian carcinomas. A first in human clinical trial evaluating NEO-201 in adults with chemo-resistant solid tumors is ongoing at the NIH clinical Center.

Abstract C033: Racial differences in the associations between luminal master regulator transcription factor expression and breast cancer survival

Purpose: Women of African ancestry in the United States are more likely to die from breast cancer than their European counterparts. While prior studies suggest differences in the frequency of hormone receptor-negative disease as an underlying cause, recent studies report higher race-based mortality rates in patients with hormone receptor-positive, luminal breast cancer. Here we explore biologic factors that may underly this disparity by comparing racial differences in the level, functional activity, and prognostic significance of 3 master transcriptional regulators of mammary luminal differentiation.

Patients and Methods: Medical records and tissues from 555 patients (293 European and 262 African ancestry) diagnosed with Stage 0 to IV breast cancer, from 2001 to 2010 at a major medical center in East North Carolina, were analyzed for the expression of functional biomarkers of luminal differentiation including estrogen receptor (ESR1), and pioneer transcription factors FOXA1 and GATA3. Differential comparison of protein expression was integrated with network-level gene expression analysis (22% of cohort) to define predictive correlations with race and survival.

Results: Univariate and multivariate odds ratios combined with area under the curve receiver operator characteristics show significant differences in predictive activity of these functional biomarkers based on race and survival—ESR1 (EA OR= 0.47, p = 5e-04; AA OR= 0.77, p = 0.22), FOXA1 (EA OR= 0.38, p= 1.4e-04; AA OR = 0.53, p = 1.3e-02), and GATA3 (EA OR= 0.36, p= 3.7e-06, AA OR= 0.57, p= 0.51)—and uncover genes in the downstream regulons of these biomarkers that strongly correlate either with genetic ancestry or overall survival.

Conclusion: Transcriptional regulatory networks linked to mammary luminal differentiation reveal race-specific differences in master regulatory activity that may underlie tumor characteristics contributing to racial disparities in outcome. These biomarkers and their downstream regulons represent important targets to explore intrinsic mechanisms that drive breast cancer survival disparities.

Citation Format: Jung S. Byun, Sandeep K. Singhal, Sam Park, Dae Ik Yi, Tingfen Yan, Ambar Caban, Alana Jones, Partha Mukhopadhyay, Sara Gil Hernandez, Stephen Hewitt, Lisa A. Newman, Melissa Davis, Jorge Sepulveda, Adrianna De Siervi, Anna Napoles, Nasreen Vohra, Kevin Gardner. Racial differences in the associations between luminal master regulator transcription factor expression and breast cancer survival [abstract]. In: Proceedings of the Eleventh AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2018 Nov 2-5; New Orleans, LA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl):Abstract nr C033.

The challenge of implementing Less is More medicine: A European perspective

The concept of Less is More medicine emerged in North America in 2010. It aims to serve as an invitation to recognize the potential risks of overuse of medical care that may result in harm rather than in better health, tackling the erroneous assumption that more care is always better. In response, several medical societies across the world launched quality-driven campaigns ("Choosing Wisely") and published "top-five lists" of low-value medical interventions that should be used to help make wise decisions in each clinical domain, by engaging patients in conversations about unnecessary tests, treatments and procedures. However, barriers and challenges for the implementation of Less is More medicine have been identified in several European countries, where overuse is rooted in the culture and demanded by a society that requests certainty at almost any cost. Patients' high expectations, physician's behavior, lack of monitoring and pernicious financial incentives have all indirect negative consequences for medical overuse. Multiple interventions and quality-measurement efforts are necessary to widely implement Less is More recommendations. These also consist of a top-five list of actions: (1) a novel cultural approach starting from medical graduation courses, up to (2) patient and society education, (3) physician behavior change with data feedback, (4) communication training and (5) policy maker interventions. In contrast with the prevailing maximization of care, the optimization of care promoted by Less is More medicine can be an intellectual challenge but also a real opportunity to promote sustainable medicine. This project will constitute part of the future agenda of the European Federation of Internal Medicine.

Pitfalls in assessing stromal tumor infiltrating lymphocytes (sTILs) in breast cancer

Stromal tumor-infiltrating lymphocytes (sTILs) are important prognostic and predictive biomarkers in triple-negative (TNBC) and HER2-positive breast cancer. Incorporating sTILs into clinical practice necessitates reproducible assessment. Previously developed standardized scoring guidelines have been widely embraced by the clinical and research communities. We evaluated sources of variability in sTIL assessment by pathologists in three previous sTIL ring studies. We identify common challenges and evaluate impact of discrepancies on outcome estimates in early TNBC using a newly-developed prognostic tool. Discordant sTIL assessment is driven by heterogeneity in lymphocyte distribution. Additional factors include: technical slide-related issues; scoring outside the tumor boundary; tumors with minimal assessable stroma; including lymphocytes associated with other structures; and including other inflammatory cells. Small variations in sTIL assessment modestly alter risk estimation in early TNBC but have the potential to affect treatment selection if cutpoints are employed. Scoring and averaging multiple areas, as well as use of reference images, improve consistency of sTIL evaluation. Moreover, to assist in avoiding the pitfalls identified in this analysis, we developed an educational resource available at www.tilsinbreastcancer.org/pitfalls.

Relationships Between Vitamin D Status and PTH over 5 Years After Roux-en-Y Gastric Bypass: a Longitudinal Cohort Study

Purpose

Secondary hyperparathyroidism (SHPT) after obesity surgery may affect bone health. Optimal vitamin D levels have not been established to prevent SHPT postoperatively. We investigated whether SHPT differed across threshold levels of serum 25-hydroxyvitamin D (S-25(OH)D) from 6 months up to 5 years after Roux-en-Y gastric bypass (RYGB).

Materials and Methods

We included 554 patients at follow-up 5 years postoperatively. Blood samples were analysed for S-25(OH)D, ionized calcium (iCa) and parathyroid hormone (PTH) during follow-up.

Results

PTH and prevalence of SHPT increased from 6 months to 5 years postoperatively, while S-25(OH)D and iCa decreased (all P < 0.001). PTH and SHPT development are related with S-25(OH)D, and PTH differed between all subgroups of S-25(OH)D. SHPT occurred less frequently across all subgroups of S-25(OH)D ≥ 50 nmol/l during follow-up: odds ratio (OR) 0.44 (95% CI 0.36–0.54) in patients with S-25(OH)D ≥ 50 nmol/l, OR 0.38 (0.30–0.49) with S-25(OH)D ≥ 75 nmol/l and OR 0.19 (0.12–0.31) with S-25(OH) D ≥ 100 nmol/l, all compared with S-25(OH)D < 50 nmol/l. At 5 years, 208/554 patients (38%) had SHPT; SHPT was found in 94/188 patients (50%) with S-25(OH)D < 50 nmol/l, in 69/222 (31%) with S-25(OH)D 50–74 nmol/l, in 40/117 (34%) with S-25(OH)D 75–99 nmol/l and in 5/27 (19%) with S-25(OH)D ≥ 100 nmol/l. An interaction existed between S-25(OH)D and iCa. Bone alkaline phosphatase remained increased with SHPT.

Conclusions

A significant relationship existed between S-25(OH)D and development of PTH and SHPT. The prevalence of SHPT was lower with threshold levels 25(OH)D ≥ 50 nmol/l and ≥ 75 nmol/l over the 5 years, and lowest with S-25(OH)D ≥ 100 nmol/l.

Electronic supplementary material

The online version of this article (10.1007/s11695-020-04582-5) contains supplementary material, which is available to authorized users.

The path to a better biomarker: application of a risk management framework for the implementation of PD-L1 and TILs as immuno-oncology biomarkers in breast cancer clinical trials and daily practice

Immune checkpoint inhibitor therapies targeting PD-1/PD-L1 are now the standard of care in oncology across several hematologic and solid tumor types, including triple negative breast cancer (TNBC). Patients with metastatic or locally advanced TNBC with PD-L1 expression on immune cells occupying ≥1% of tumor area demonstrated survival benefit with the addition of atezolizumab to nab-paclitaxel. However, concerns regarding variability between immunohistochemical PD-L1 assay performance and inter-reader reproducibility have been raised. High tumor-infiltrating lymphocytes (TILs) have also been associated with response to PD-1/PD-L1 inhibitors in patients with breast cancer (BC). TILs can be easily assessed on hematoxylin and eosin-stained slides and have shown reliable inter-reader reproducibility. As an established prognostic factor in early stage TNBC, TILs are soon anticipated to be reported in daily practice in many pathology laboratories worldwide. Because TILs and PD-L1 are parts of an immunological spectrum in BC, we propose the systematic implementation of combined PD-L1 and TIL analyses as a more comprehensive immuno-oncological biomarker for patient selection for PD-1/PD-L1 inhibition-based therapy in patients with BC. Although practical and regulatory considerations differ by jurisdiction, the pathology community has the responsibility to patients to implement assays that lead to optimal patient selection. We propose herewith a risk-management framework that may help mitigate the risks of suboptimal patient selection for immuno-therapeutic approaches in clinical trials and daily practice based on combined TILs/PD-L1 assessment in BC. © 2020 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Ultrastructural Characterization of Proteinuric Patients Predicts Clinical Outcomes

BACKGROUND

The analysis and reporting of glomerular features ascertained by electron microscopy are limited to few parameters with minimal predictive value, despite some contributions to disease diagnoses.

METHODS

We investigated the prognostic value of 12 electron microscopy histologic and ultrastructural changes (descriptors) from the Nephrotic Syndrome Study Network (NEPTUNE) Digital Pathology Scoring System. Study pathologists scored 12 descriptors in NEPTUNE renal biopsies from 242 patients with minimal change disease or FSGS, with duplicate readings to evaluate reproducibility. We performed consensus clustering of patients to identify unique electron microscopy profiles. For both individual descriptors and clusters, we used Cox regression models to assess associations with time from biopsy to proteinuria remission and time to a composite progression outcome (≥40% decline in eGFR, with eGFR<60 ml/min per 1.73 m², or ESKD), and linear mixed models for longitudinal eGFR measures.

RESULTS

Intrarater and interrater reproducibility was >0.60 for 12 out of 12 and seven out of 12 descriptors, respectively. Individual podocyte descriptors such as effacement and microvillous transformation were associated with complete remission, whereas endothelial cell and glomerular basement membrane abnormalities were associated with progression. We identified six descriptor-based clusters with distinct electron microscopy profiles and clinical outcomes. Patients in a cluster with more prominent foot process effacement and microvillous transformation had the highest rates of complete proteinuria remission, whereas patients in clusters with extensive loss of primary processes and endothelial cell damage had the highest rates of the composite progression outcome.

CONCLUSIONS

Systematic analysis of electron microscopic findings reveals clusters of findings associated with either proteinuria remission or disease progression.

Health benefits and risks during 10 years after Roux-en-Y gastric bypass

Background

Long-term evaluations 10 years after Roux-en-Y gastric bypass (RYGB) are limited. We report the development in weight and cardiovascular risk factors during 10 years after laparoscopic RYGB, with evaluation of gastrointestinal symptoms and quality of life (QoL) at 10-year follow-up.

Methods

We performed a prospective longitudinal cohort study. Patients operated with laparoscopic RYGB from May 2004 to November 2006 were invited to 10-year follow-up consultations. Gastrointestinal Symptom Rating Scale (GSRS) questionnaire and two QoL questionnaires were used for analyses of gastrointestinal symptoms and QoL.

Results

A total of 203 patients were operated; nine (4.4%) died during follow-up. Of 194 eligible patients, 124 (63.9%) attended 10-year follow-up consultations. Percent excess weight loss (%EWL) and percent total weight loss (%TWL) at 10 years were 53.0% and 24.1%, respectively. %EWL > 50% was seen in 53.2%. Significant weight regain (≥15%) from 2 to 10 years was seen in 63.3%. Remission rates of type 2 diabetes, dyslipidemia, and hypertension were 56.8%, 46.0%, and 41.4%, respectively. Abdominal operations beyond 30 days after RYGB were reported in 33.9%. Internal hernia and ileus (13.7%) and gallstone-related disease (9.7%) were the most common causes. Vitamin D deficiency (<50nmol/L) was seen in 33.3%. At 10 years, bothersome abdominal pain and indigestion symptoms (GSRS scores ≥3) were reported in 42.9% and 54.0%, respectively, and were associated with low QoL.

Conclusion

We observed significant weight loss and remission of comorbidities 10 years after RYGB. Significant weight regain occurred in a substantial subset of patients. Gastrointestinal symptoms were common and negatively impacted QoL.

Application of convolutional neural networks to breast biopsies to delineate tissue correlates of mammographic breast density

Breast density, a breast cancer risk factor, is a radiologic feature that reflects fibroglandular tissue content relative to breast area or volume. Its histology is incompletely characterized. Here we use deep learning approaches to identify histologic correlates in radiologically-guided biopsies that may underlie breast density and distinguish cancer among women with elevated and low density. We evaluated hematoxylin and eosin (H&E)-stained digitized images from image-guided breast biopsies (n = 852 patients). Breast density was assessed as global and localized fibroglandular volume (%). A convolutional neural network characterized H&E composition. In total 37 features were extracted from the network output, describing tissue quantities and morphological structure. A random forest regression model was trained to identify correlates most predictive of fibroglandular volume (n = 588). Correlations between predicted and radiologically quantified fibroglandular volume were assessed in 264 independent patients. A second random forest classifier was trained to predict diagnosis (invasive vs. benign); performance was assessed using area under receiver-operating characteristics curves (AUC). Using extracted features, regression models predicted global (r = 0.94) and localized (r = 0.93) fibroglandular volume, with fat and non-fatty stromal content representing the strongest correlates, followed by epithelial organization rather than quantity. For predicting cancer among high and low fibroglandular volume, the classifier achieved AUCs of 0.92 and 0.84, respectively, with epithelial organizational features ranking most important. These results suggest non-fatty stroma, fat tissue quantities and epithelial region organization predict fibroglandular volume. The model holds promise for identifying histological correlates of cancer risk in patients with high and low density and warrants further evaluation.

Associations of tobacco smoking with body mass distribution; a population-based study of 65,875 men and women in midlife

BACKGROUND

Studies indicate an effect of smoking toward abdominal obesity, but few assess hip and waist circumferences (HC and WC) independently. The present study aimed to assess the associations of smoking status and volume smoked with HC and WC and their ratio in a population with low prevalence of obesity together with high prevalence of smoking.

METHODS

We used cross-sectional survey data from 11 of a total 19 Norwegian counties examined in 1997-99 including 65,875 men and women aged 39-44 years. Analysis of associations were adjusted for confounding by socioeconomic position, health indicators, and additionally for BMI.

RESULTS

Compared with never-smokers, when adjusting for confounders and in addition for BMI, mean HC remained lower while mean WC and waist-hip-ratio (WHR) were higher in current smokers. The finding of a lower HC and higher WHR level among smokers was consistent by sex and in strata by levels of education and physical activity, while the finding of higher WC by smoking was less consistent. Among current smokers, BMI-adjusted mean HC decreased whereas WC and WHR increased by volume smoked. Compared with current smokers, former smokers had higher BMI-adjusted HC, lower WHR and among women WC was lower.

CONCLUSIONS

The main finding in this study was the consistent negative associations of smoking with HC. In line with the hypothesis that lower percentage gluteofemoral fat is linked with higher cardiovascular risk, our results suggest that smoking impacts cardiovascular risk through mechanisms that reduce the capacity of fat storage in the lower body region.

Bone metabolism, bone mineral density and low-energy fractures 10 years after Roux-en-Y gastric bypass

BACKGROUND

Roux-en-Y gastric bypass (RYGB) is a common surgical procedure for treatment of morbid obesity. RYGB induces considerable and sustained weight loss, and remission of obesity related-comorbidities. While studies have suggested negative effects of RYGB on bone health, long-term data are lacking. We aimed to evaluate the prevalence of aBMD below the expected range for age, osteopenia, osteoporosis and low-energy fractures in a defined patient cohort 10 years after RYGB. Secondly, we wanted to identify factors associated with increased risk of aBMD z-score or t-score of -1.1 or lower 10 years after RYGB.

METHODS

Patients undergoing RYGB surgery from June 2004 to December 2006 at the Department of Morbid Obesity and Bariatric Surgery, Oslo University Hospital, a tertiary referral centre for treatment of morbid obesity, were invited to a 10 year follow-up. Follow-up visits included morning fasting blood samples, clinical examination, anthropometric measures and dual energy X-ray absorptiometry (DXA).

RESULTS

Out of 194 patients eligible for the study, 124 attended the 10 year follow-up and 122 (63%) were examined with DXA. Mean (SD) age was 50.3 (9.0) years, 118 (97%) were of Caucasian ethnicity, 94 were females (77%), of whom 41 (44%) were postmenopausal. Secondary hyperparathyroidism (SHPT) was noted in 37 participants (31%) and vitamin D deficiency (value below 50 nmol/L) and insufficiency (value below 75 nmol/L) in 40 (33%) and 91 (75%), respectively. Among the 63 participants who were premenopausal females or males 49 years or younger the prevalence of areal bone mineral density (aBMD) in the lower range of normal (z-score -1.1- to -1.9) was 30% (n = 19) and aBMD below the expected range for age (z-score ≤ -2.0) was noted in 8% (n = 5). Among the 59 participants who were postmenopausal females or males 50 years or older, the prevalence of osteopenia (t-score -1.1 to -2.4) was 51% (n = 30) and osteoporosis (t-score ≤ -2.5) was 27% (n = 16). The bone resorption markers CTX-1 and PINP were higher in participants with aBMD z-score or t-score of -1.1 or lower compared to participants with aBMD z-score or t-score of -1.0 or higher. Preoperative hypothyroidism, or higher age, postmenopausal status, BMI < 35 kg/m², SHPT or higher PINP levels at 10 year follow-up were independently associated with aBMD z-score or t-score of -1.1 or lower 10 years after RYGB. Eighteen participants (15%) reported a clinical low-energy fracture after RYGB. In addition, vertebral fracture assessment by DXA revealed that 10 participants (8%) had experienced at least one moderate to severe morphometric vertebral fracture.

CONCLUSION

Ten years after RYGB 27% of postmenopausal females and males 50 years or older were osteoporotic, and 8% of premenopausal females and males 49 years or younger exhibited aBMD below the expected range for age. The prevalence of fragility fractures was high. SHPT, higher age, postmenopausal status or higher PINP levels at 10 years and preoperative hypothyroidism were all independent risk factors for aBMD z-score or t-score of -1.1 or lower 10 years after RYGB.

No evidence of ongoing HIV replication or compartmentalization in tissues during combination antiretroviral therapy: Implications for HIV eradication

HIV persistence during combination antiretroviral therapy (cART) is the principal obstacle to cure. Mechanisms responsible for persistence remain uncertain; infections may be maintained by persistence and clonal expansion of infected cells or by ongoing replication in anatomic locations with poor antiretroviral penetration. These mechanisms require different strategies for eradication, and determining their contributions to HIV persistence is essential. We used phylogenetic approaches to investigate, at the DNA level, HIV populations in blood, lymphoid, and other infected tissues obtained at colonoscopy or autopsy in individuals who were on cART for 8 to 16 years. We found no evidence of ongoing replication or compartmentalization of HIV; we did detect clonal expansion of infected cells that were present before cART. Long-term persistence, and not ongoing replication, is primarily responsible for maintaining HIV. HIV-infected cells present when cART is initiated represent the only identifiable source of persistence and is the appropriate focus for eradication.

Abstract 2311: Analysis of glypican 3-targeted chimeric antigen receptor T cells in hepatocellular carcinoma cell and mouse models

Background: Glypican-3 (GPC3) is a cell surface protein that is highly expressed in hepatocellular carcinoma (HCC).

Methods and Results: In this report, we analyzed two chimeric antigen receptors (CARs) targeting GPC3, CAR (HN3) recognizes the N-lobe of GPC3 while CAR (hYP7) targets the C-lobe that is close to the cell surface. In a real-time cell cytolytic assay, we found that CAR (hYP7) T cells showed higher cytolytic activity than CAR(HN3) T cells at an E:T ratio of 2:1 when co-cultured with HepG2 cells for up to 140 hours. The Luminex analysis showed that CAR (hYP7) T cells produced significantly more Th1/Th2 cytokines and chemokines than CAR (HN3) T cells following exposure to Hep3B and HepG2 cells. In the Hep3B peritoneal dissemination xenograft mouse model, a single intraperitoneal infusion of CAR (hYP7) cells exhibited sustainable antitumor efficacy, and all of the mice survived without recurrence 10 weeks post treatment. Strikingly, we demonstrated that single injection of CAR (hYP7) T cells derived from either healthy donor or HCC patient significantly regressed tumor growth in the orthotopic HCC mouse model. Using a highly sensitive droplet digital PCR (ddPCR), we detected high frequencies of CAR T cells in the spleen and tumor microenvironment of mice in the CAR (hYP7) group. By contrast, CD19 CAR T cells showed no sign of gene integration in either tissue. More importantly, we found that CD8+ CAR (hYP7) T cells recovered from mouse spleens exhibited much higher lytic activity against HCC cells than CD4+ CAR (hYP7) T cells. Finally, we found that the GPC3-targeted CAR T cells downregulated the Wnt signaling in HCC cells.

Conclusion: The hYP7 antibody-derived GPC3-specific CAR is a promising therapeutic that could be tested for the treatment of advanced stage liver cancer.

Citation Format: Dan Li, Nan Li, Yifan Zhang, Haiying Fu, Zhijian Duan, Alissa Hummer, Hongjia Yang, Madeline B. Torres, Xiaoling Luo, Ling Su, Hu Zhu, Josh Kramer, Jinqiu Chen, Xiaolin Wu, Matthew Hall, Qun Wang, Stephen Hewitt, Tim Greten, Mitchell Ho. Analysis of glypican 3-targeted chimeric antigen receptor T cells in hepatocellular carcinoma cell and mouse models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2311.

Abstract 5033: The role of the epigenetic regulator SATB2 in colon cancer progression

SATB2 is a nuclear matrix-associated transcription factor that orchestrates gene expression by regulating higher-order chromatin structure. Using antibody-based screening of 48 normal human tissues and 20 cancer types, we identified SATB2 as a protein almost exclusively expressed in gastrointestinal tissue. We confirmed this observation at the mRNA level in 10,533 human tissue samples. Differential expression of SATB2 was observed in colorectal cancer, with loss of expression occurring along the adenoma-carcinoma sequence. Additionally, SATB2 expression was markedly decreased in metastatic SW620 colon cancer cells and siRNA knockdown of SATB2 expression in parental SW480 cells increased their growth and migratory capacity. Ectopic expression of SATB2 in the metastatic variant reversed the observed phenotype. Using tissue microarray and automated image analysis of SATB2 expression in colorectal cancers (n=309), SATB2 was demonstrated by multivariate Cox regression analysis to be an independent predictor of disease-specific survival (HR=0.52, 95% CI 0.32-0.83, p=0.006). SATB2 mRNA levels were examined in a second cohort (n=290) and again, SATB2 was demonstrated to be an independent predictor of disease-specific survival (HR=0.40, 95% CI 0.18-0.92, p=0.031). Interestingly, in colorectal cancer patients, SATB2 levels significantly correlated with CD3+ T-cell infiltrates in the tumours (p=0.006) and inversely correlated with COX2 expression (p=0.019). In two independent colorectal cancer cohorts (n=467), SATB2-low tumours were found to be significantly enriched in the CMS1 (immune-related) subtype (p&lt;0.001). Gene set enrichment analysis revealed that SATB2 low tumours demonstrated altered immune signalling with significant increases in IFNγ (p=0.001), IL6 (p=0.001), IL8 (p&lt;0.001) TFGβ (p&lt;0.001), which was mirrored by in vitro manipulation of SATB2 expression in colon cancer cells. Furthermore, in a longitudinal cohort of patients with ulcerative colitis, we observed a significant correlation between loss of SATB2 expression and occurrence of future cancers (p=0.013). We therefore postulate that SATB2 acts as a master regulator of the inflammatory response in the gut and loss of expression is significantly associated with the progression of colorectal cancer.

Citation Format: Donal J. Brennan, Kirsha Naicker, Sudipto Das, Bruce Moran, Rut Klinger, Fredrik Ponten, Stephen Hewitt, Karin Jirström, Annette T. Byrne, Jacintha O'Sullivan, William M. Gallagher, Darran P. O'Connor. The role of the epigenetic regulator SATB2 in colon cancer progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 5033.

Durvalumab in Combination with Olaparib in Patients with Relapsed SCLC: Results from a Phase II Study

PURPOSE

Despite high tumor mutationburden, immune checkpoint blockade has limited efficacy in SCLC. We hypothesized that poly (ADP-ribose) polymerase inhibition could render SCLC more susceptible to immune checkpoint blockade.

METHODS

A single-arm, phase II trial (NCT02484404) enrolled patients with relapsed SCLC who received durvalumab, 1500 mg every 4 weeks, and olaparib, 300 mg twice a day. The primary outcome was objective response rate. Correlative studies included mandatory collection of pretreatment and during-treatment biopsy specimens, which were assessed to define SCLC immunephenotypes: desert (CD8-positive T-cell prevalence low), excluded (CD8-positive T cells in stroma immediately adjacent/within tumor), and inflamed (CD8-positive T cells in direct contact with tumor).

RESULTS

A total of 20 patients were enrolled. Their median age was 64 years, and most patients (60%) had platinum-resistant/refractory disease. Of 19 evaluable patients, two were observed to have partial or complete responses (10.5%), including a patient with EGFR-transformed SCLC. Clinical benefit was observed in four patients (21.1% [95% confidence interval: 6.1%-45.6%]) with confirmed responses or prolonged stable disease (≥8 months). The most common treatment-related adverse events were anemia (80%), lymphopenia (60%), and leukopenia (50%). Nine of 14 tumors (64%) exhibited an excluded phenotype; 21% and 14% of tumors exhibited the inflamed and desert phenotypes, respectively. Tumor responses were observed in all instances in which pretreatment tumors showed an inflamed phenotype. Of the five tumors without an inflamed phenotype at baseline, no during-treatment increase in T-cell infiltration or programmed death ligand 1 expression on tumor-infiltrating immune cells was observed.

CONCLUSIONS

The study combination did not meet the preset bar for efficacy. Pretreatment and during-treatment biopsy specimens suggested that tumor immune phenotypes may be relevant for SCLC responses to immune checkpoint blockade combinations. The predictive value of preexisting CD8-positive T-cell infiltrates observed in this study needs to be confirmed in larger cohorts.

Two ICD Inducers are better than one for induction of anti-tumor immunity in cold carcinomas

Background

Cytotoxic agents and viruses cause Immunogenic Cell Death (ICD), which initiates a primary immune response in tumor-bearing hosts by releasing cellular antigens with immune chaperones. We postulate that two ICD inducers are better than one in immune competent mouse models of colorectal and breast cancer.

Methods

Approximately 6 mm diameter CT26 rectal or 4T1 breast carcinomas were established in groups of 5–7 BALB/c mice and injected once intratumorally (IT) with oxaliplatin (OX) mixed with a human adenovirus AdV optimized for calreticulin externalization in 3-D spheroids of human carcinomas. Tumor volumes were measured every other day and rate of growth analyzed by Rate-Based T/C Ratio at 19–21 days. Tumor-Infiltrating Lymphocytes (TIL) and nodal cytotoxicity were assessed 11 days after treatment.

Results

In 3 experiments with OX-AdV IT in PBS buffer the T/C ratios were 0.17–0.29 those of the volume of PBS IT injected mice. The T/C Ratio for OX-AdV IT in D5W (used to stabilize the OX) was 0.10 of the IT control volume with 0.32–0.40 for OX or AdV alone and with all groups different by P&lt;0.05 by 2-way ANOVA. OX-AdV IT increased TIL by 4-fold and decreased CD8+PD-1+EOMES+ from 79% to 19% with a dramatic influx of CD8+PD-1-Eomes- T cells compared to PBS IT controls. Draining node lymphocytes were cytotoxic to CT26 cells from OX-AdV IT mice while lymphocytes from PBS IT mice were not. OX-AdV IT in D5W caused 40% of mice to be complete responders that later rejected a contralateral challenge of CT26.

Conclusions

The buffer for IT treatment with OX is critical. The two ICD inducer formulation with D5W is promising as a checkpoint therapy sensitizer for carcinomas that lack TIL or resist checkpoint inhibitor therapy like colorectal carcinoma.

Etiology of hormone receptor positive breast cancer differs by levels of histologic grade and proliferation

Limited epidemiological evidence suggests that the etiology of hormone receptor positive (HR+) breast cancer may differ by levels of histologic grade and proliferation. We pooled risk factor and pathology data on 5,905 HR+ breast cancer cases and 26,281 controls from 11 epidemiological studies. Proliferation was determined by centralized automated measures of KI67 in tissue microarrays. Odds ratios (OR), 95% confidence intervals (CI) and p-values for case-case and case-control comparisons for risk factors in relation to levels of grade and quartiles (Q1-Q4) of KI67 were estimated using polytomous logistic regression models. Case-case comparisons showed associations between nulliparity and high KI67 [OR (95% CI) for Q4 vs. Q1 = 1.54 (1.22, 1.95)]; obesity and high grade [grade 3 vs. 1 = 1.68 (1.31, 2.16)] and current use of combined hormone therapy (HT) and low grade [grade 3 vs. 1 = 0.27 (0.16, 0.44)] tumors. In case-control comparisons, nulliparity was associated with elevated risk of tumors with high but not low levels of proliferation [1.43 (1.14, 1.81) for KI67 Q4 vs. 0.83 (0.60, 1.14) for KI67 Q1]; obesity among women ≥50 years with high but not low grade tumors [1.55 (1.17, 2.06) for grade 3 vs. 0.88 (0.66, 1.16) for grade 1] and HT with low but not high grade tumors [3.07 (2.22, 4.23) for grade 1 vs. 0.85 (0.55, 1.30) for grade 3]. Menarcheal age and family history were similarly associated with HR+ tumors of different grade or KI67 levels. These findings provide insights into the etiologic heterogeneity of HR+ tumors.

Anemia following Roux-en-Y gastric bypass for morbid obesity; a 5-year follow-up study

OBJECTIVES

Patients are at risk of anemia post Roux-en-Y gastric bypass (RYGB). We sought to determine the prevalence of anemia and related nutritional deficiencies 5 years after RYGB and to evaluate adherence to nutritional supplements with iron, vitamin B12, and folate.

MATERIAL AND METHODS

Patients operated with RYGB 2004-2006 were eligible for evaluation. Blood samples were collected and use of nutritional supplements was recorded preoperatively, and at outpatients' consultations 1, 2, and 5 years postoperatively. Of 203 patients operated, 184 (91%) completed the 5 year follow-up and were included in the study. Of these, 97% had valid measurements of hemoglobin both at baseline and after 5 years.

RESULTS

During the 5 years after RYGB, the prevalence of anemia increased from 4% preoperatively to 24% in females, and from 0% to 7% in males. Ferritin levels decreased gradually in both genders. Iron deficiency increased from 6% preoperatively to 42% at 5 years in females, and from 0% to 9% in males. Vitamin B12 deficiency was not altered while folate deficiency decreased from 10% preoperatively to 1% at 5 years. Five years after surgery 25% reported the use of supplements with iron, while 83% used vitamin B12 and 65% used multivitamins with folate.

CONCLUSIONS

We observed a long-term increase in anemia and iron deficiency after RYGB in both genders, but most pronounced in women. Our postoperative protocol for prevention of vitamin B12 and folate deficiencies appear acceptable. Iron status and iron supplementation seems to need stronger emphasis during follow-up after RYGB.

Increased High Molecular Weight FGF2 in Endocrine-Resistant Breast Cancer

Endocrine resistance may develop as a consequence of enhanced growth factor signaling. Fibroblast growth factor 2 (FGF2) consists of a low and several high molecular weight forms (HMW-FGF2). We previously demonstrated that antiprogestin-resistant mammary carcinomas display lower levels of progesterone receptor A isoforms (PRA) than B isoforms (PRB). Our aim was to evaluate the role of FGF2 isoforms in breast cancer progression. We evaluated FGF2 expression, cell proliferation, and pathway activation in models with different PRA/PRB ratios. We performed lentiviral infections of different FGF2 isoforms using the human hormone-responsive T47D-YA cells, engineered to only express PRA, and evaluated tumor growth, metastatic dissemination, and endocrine responsiveness. We assessed FGF2 expression and localization in 81 human breast cancer samples. Antiprogestin-resistant experimental mammary carcinomas with low PRA/PRB ratios and T47D-YB cells, which only express PRB, displayed higher levels of HMW-FGF2 than responsive variants. HMW-FGF2 overexpression in T47D-YA cells induced increased tumor growth, lung metastasis, and antiprogestin resistance compared to control tumors. In human breast carcinomas categorized by their PRA/PRB ratio, we found nuclear FGF2 expression in 55.6% of tumor cells. No differences were found between nuclear FGF2 expression and Ki67 proliferation index, tumor stage, or tumor grade. In low-grade tumor samples, moderate to high nuclear FGF2 levels were associated to carcinomas with low PRA/PRB ratio. In conclusion, we show that HMW-FGF2 isoforms are PRB targets which confer endocrine resistance and are localized in the nuclei of breast cancer samples. Hence, targeting intracellular FGF2 may contribute to overcome tumor progression.

Relationships of serum 25-hydroxyvitamin D, ionized calcium and parathyroid hormone after obesity surgery

OBJECTIVE

The high prevalence of secondary hyperparathyroidism (SHPT) after obesity surgery is a concern for long-term bone health. Limited knowledge exists about optimal vitamin D and suppression of parathyroid hormone (PTH) after these procedures. The aim of this study was to investigate the prevalence of SHPT and its relation to vitamin D status.

DESIGN

A cross-sectional study at Oslo University Hospital, Norway.

PATIENTS

A total of 502 consecutive patients, age 22-64 years, attending 2-year follow-up after Roux-en-Y gastric bypass.

MEASUREMENTS

A serum intact PTH >7.0 pmol/L in the absence of elevated serum ionized calcium (iCa) was considered as SHPT. Vitamin D status was defined by serum concentrations of 25-hydroxyvitamin D (S-25(OH)D).

RESULTS

Altogether, 171 patients (34%) had SHPT. The prevalence of SHPT varied across the range of S-25(OH)D (P < 0.001), being highest (71%) with S-25(OH)D < 25 nmol/L. Compared with S-25(OH)D < 50 nmol/L, the prevalence of SHPT was lower with S-25(OH)D ≥ 50 nmol/L (29.0%; RR = 0.64 (95%-CI:0.50-0.81)) and S-25(OH)D ≥ 75 nmol/L (27.7%; RR = 0.61 (95%-CI:0.44-0.84)). S-25(OH)D ≥ 100 nmol/L was associated with the lowest PTH and the lowest prevalence of SHPT (16.0%; RR = 0.35 (95%-CI:0.14-0.88) compared with S-25(OH)D < 50 nmol/L) and the most normal calcium distribution. These associations were most pronounced with iCa in the lower range. A synergistic association was found for S-25(OH)D and iCa on SHPT.

CONCLUSIONS

Vitamin D deficient patients had the highest prevalence of SHPT 2 years after gastric bypass. PTH and the prevalence of SHPT were notably lower with S-25(OH)D ≥ 100 nmol/L, compared with lower target levels.

Assessing Tumor-Infiltrating Lymphocytes in Solid Tumors: A Practical Review for Pathologists and Proposal for a Standardized Method from the International Immuno-Oncology Biomarkers Working Group: Part 2: TILs in Melanoma, Gastrointestinal Tract Carcinomas, Non-Small Cell Lung Carcinoma and Mesothelioma, Endometrial and Ovarian Carcinomas, Squamous Cell Carcinoma of the Head and Neck, Genitourinary Carcinomas, and Primary Brain Tumors

Assessment of the immune response to tumors is growing in importance as the prognostic implications of this response are increasingly recognized, and as immunotherapies are evaluated and implemented in different tumor types. However, many different approaches can be used to assess and describe the immune response, which limits efforts at implementation as a routine clinical biomarker. In part 1 of this review, we have proposed a standardized methodology to assess tumor-infiltrating lymphocytes (TILs) in solid tumors, based on the International Immuno-Oncology Biomarkers Working Group guidelines for invasive breast carcinoma. In part 2 of this review, we discuss the available evidence for the prognostic and predictive value of TILs in common solid tumors, including carcinomas of the lung, gastrointestinal tract, genitourinary system, gynecologic system, and head and neck, as well as primary brain tumors, mesothelioma and melanoma. The particularities and different emphases in TIL assessment in different tumor types are discussed. The standardized methodology we propose can be adapted to different tumor types and may be used as a standard against which other approaches can be compared. Standardization of TIL assessment will help clinicians, researchers and pathologists to conclusively evaluate the utility of this simple biomarker in the current era of immunotherapy.

Assessing Tumor-infiltrating Lymphocytes in Solid Tumors: A Practical Review for Pathologists and Proposal for a Standardized Method From the International Immunooncology Biomarkers Working Group: Part 1: Assessing the Host Immune Response, TILs in Invasive Breast Carcinoma and Ductal Carcinoma In Situ, Metastatic Tumor Deposits and Areas for Further Research

Assessment of tumor-infiltrating lymphocytes (TILs) in histopathologic specimens can provide important prognostic information in diverse solid tumor types, and may also be of value in predicting response to treatments. However, implementation as a routine clinical biomarker has not yet been achieved. As successful use of immune checkpoint inhibitors and other forms of immunotherapy become a clinical reality, the need for widely applicable, accessible, and reliable immunooncology biomarkers is clear. In part 1 of this review we briefly discuss the host immune response to tumors and different approaches to TIL assessment. We propose a standardized methodology to assess TILs in solid tumors on hematoxylin and eosin sections, in both primary and metastatic settings, based on the International Immuno-Oncology Biomarker Working Group guidelines for TIL assessment in invasive breast carcinoma. A review of the literature regarding the value of TIL assessment in different solid tumor types follows in part 2. The method we propose is reproducible, affordable, easily applied, and has demonstrated prognostic and predictive significance in invasive breast carcinoma. This standardized methodology may be used as a reference against which other methods are compared, and should be evaluated for clinical validity and utility. Standardization of TIL assessment will help to improve consistency and reproducibility in this field, enrich both the quality and quantity of comparable evidence, and help to thoroughly evaluate the utility of TILs assessment in this era of immunotherapy.

Abstract 4718: Filamin A interacting protein 1-like is a marker of prognosis, progression and chemosensitivity in ovarian cancer

Purpose: The WNT/β-catenin pathway and the resulting epithelial-to-mesenchymal transition (EMT) play a key role in ovarian cancer progression and chemoresistance. Filamin A interacting protein 1-like (FILIP1L) enhances β-catenin degradation, thereby inhibiting canonical WNT signaling and EMT. FILIP1L is a tumor suppressor whose expression is down-regulated by promoter hyper-methylation in ovarian cancer. FILIP1L down-regulation is inversely correlated with the invasive potential of ovarian cancer cells. However, the clinical relevance of FILIP1L down-regulation in ovarian cancer progression has yet to be addressed.

Experimental design: To study the clinical implications of FILIP1L in regulating the WNT/β-catenin pathway and chemoresistance, the expression of FILIP1L, β-catenin, SNAIL and SLUG was analyzed by immunohistochemistry on tissue microarrays of 369 ovarian samples ranging from normal to metastatic. Their expression was evaluated with clinicopathological characteristics including FIGO stage and chemosensitivity, and correlated with overall and disease-free survival by Kaplan-Meier plots and Cox proportional hazards model.

Results: We demonstrated that FILIP1L expression decreased with tumor progression, resulting in a significant difference between primary and metastatic ovarian cancer samples. In contrast, levels of β-catenin and SLUG increased with tumor progression. Furthermore, tumors that were resistant to platinum/paclitaxel combination therapy showed a significant reduction in FILIP1L expression when compared to sensitive tumors, contrary to SLUG expression, which was significantly higher. The expression of FILIP1L was negatively correlated with the expression of β-catenin and SLUG, whereas β-catenin expression was positively correlated with SLUG expression, suggesting a link between FILIP1L and the WNT/β-catenin pathway in ovarian cancer. Moreover, patients with low FILIP1L expression showed a median overall survival and disease-free survival of 60 and 19 months, respectively, whereas patients with high FILIP1L expression had not yet reached median overall and disease-free survival at their 120 month follow-up. Notably, low FILIP1L expression was independent negative prognostic factor with respect to overall and disease-free survival.

Conclusions: Our study provides the first clinical relevance of FILIP1L in human cancer, and suggests that FILIP1L may be a novel biomarker for good prognosis and lower probability of recurrence in ovarian cancer patients.

Citation Format: Mijung Kwon, Jae-Hoon Kim, Chel Hun Choi, Joon-Yong Chung, Stephen Hewitt, Steven Libutti. Filamin A interacting protein 1-like is a marker of prognosis, progression and chemosensitivity in ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4718. doi:10.1158/1538-7445.AM2017-4718

Abstract 2927: Proteogenomic heterogeneity in metastatic lung adenocarcinoma revealed from rapid/warm autopsy

Introduction: Intratumor heterogeneity has been characterized among multiple cancer types. However, in lung adenocarcinoma, recent work has been limited to early stage primary tumors and intertumor heterogeneity has not been well-studied. Most importantly, an integrated tumor heterogeneity analysis at the level of somatic variants, copy number, transcript and protein expression, and the phosphoproteome is outstanding.

Methods: In order to characterize both intra-tumor and inter-tumor heterogeneity of metastatic lung adenocarcinoma, we applied whole exome sequencing, RNA-seq, CNV-seq and mass spectrometry-based proteomic analyses on 33 tumor regions from metastatic sites including lung, liver and kidney, obtained by rapid/warm autopsy from 4 patients with Stage IV lung adenocarcinoma. The autopsy procedure was initiated between 2-4 hours of death.

Results: We found considerable intertumor heterogeneity with organ-specific, branched evolution that was consistent across DNA, RNA and protein analyses. Intratumor heterogeneity differed depending on oncogene-status: oncogene-negative tumors (without RTK/RAS/RAF mutations or known fusion gene) had significantly higher genomic intratumor heterogeneity than oncogene positive tumors. The degree of heterogeneity at the genomic and proteomic level was patient-specific. The proteomic analysis complemented genomic variants-based clonal evolution analysis. High-confidence driver mutations (KRAS, EGFR, TP53, CTNNB1) uniformly occurred early in the evolution of metastatic lung adenocarcinoma consistent with the concept of these mutations as likely ‘founders’. In contrast, other known driver mutations occurred more often in later stages among specific organ branches. Notably, oncogene-negative tumors carried significantly more driver mutations than oncogene-positive tumors suggesting that genomic alterations may have a larger role in the metastatic process versus the early evolution of lung adenocarcinoma in oncogene-negative vs. oncogene-positive tumors. Among all patients, lung cancer specific focal copy number alterations frequently occurred within metastatic branch points. Single metastatic site biopsies would therefore be unlikely to capture all significant driver mutations and copy number alterations, particularly among oncogene-negative tumors.

Conclusion: Metastatic lung adenocarcinoma evolves through a branched, organ-specific, process with acquisition of significant driver mutations and copy number changes, particularly among oncogene-negative tumors. The branched evolution is ultimately influenced by proteomic and phosphoproteomic alterations affecting key signaling pathways that may not be always a result of genomic changes.

Citation Format: Nitin Roper, Tapan K. Maity, James Gao, Abhilash Venugopalan, Xu Zhang, Romi Biswas, Constance Cultraro, David Kleiner, Stephen Hewitt, Javed Khan, Guha Udayan. Proteogenomic heterogeneity in metastatic lung adenocarcinoma revealed from rapid/warm autopsy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2927. doi:10.1158/1538-7445.AM2017-2927

Discovery and validation of candidate host DNA methylation markers for detection of cervical precancer and cancer

Human papillomavirus (HPV) testing has been recently introduced as an alternative to cytology for cervical cancer screening. However, since most HPV infections clear without causing clinically relevant lesions, additional triage tests are required to identify women who are at high risk of developing cancer. We performed DNA methylation profiling on formalin-fixed, paraffin-embedded tissue specimens from women with benign HPV16 infection and histologically confirmed cervical intraepithelial neoplasia grade 3, and cancer using a bead-based microarray covering 1,500 CpG sites in over 800 genes. Methylation levels in individual CpG sites were compared using a t-test, and results were summarized by computing p-values. A total of 12 candidate genes (ADCYAP1, ASCL1, ATP10, CADM1, DCC, DBC1, HS3ST2, MOS, MYOD1, SOX1, SOX17 and TMEFF2) identified by DNA methylation profiling, plus an additional three genes identified from the literature (EPB41L3, MAL and miR-124) were chosen for validation in an independent set of 167 liquid-based cytology specimens using pyrosequencing and targeted, next-generation bisulfite sequencing. Of the 15 candidate gene markers, 10 had an area under the curve (AUC) of ≥ 0.75 for discrimination of high grade squamous intraepithelial lesions or worse (HSIL+) from <HSIL cytology using at least one assay. Overall, SOX1, DCC, and EPB41L3 showed the best discrimination with AUC values of ≥0.80, irrespective of methylation detection assay. In addition to verifying candidate markers from the literature (e.g., SOX1 and EPB41L3), we identified novel markers that may be considered for detection of cervical precancer and cancer and warrant further validation in prospective studies.

Progesterone Receptor Isoform Ratio: A Breast Cancer Prognostic and Predictive Factor for Antiprogestin Responsiveness

Background

Compelling evidence shows that progestins regulate breast cancer growth. Using preclinical models, we demonstrated that antiprogestins are inhibitory when the level of progesterone receptor isoform A (PR-A) is higher than that of isoform B (PR-B) and that they might stimulate growth when PR-B is predominant. The aims of this study were to investigate ex vivo responses to mifepristone (MFP) in breast carcinomas with different PR isoform ratios and to examine their clinical and molecular characteristics.

Methods

We performed human breast cancer tissue culture assays (n = 36) to evaluate the effect of MFP on cell proliferation. PR isoform expression was determined by immunoblotting (n = 282). Tumors were categorized as PRA-H (PR-A/PR-B ≥ 1.2) or PRB-H (PR-A/PR-B ≤ 0.83). RNA was extracted for Ribo-Zero-Seq sequencing to evaluate differentially expressed genes. Subtypes and risk scores were predicted using the PAM50 gene set, the data analyzed using The Cancer Genome Atlas RNA-seq gene analysis and other publicly available gene expression data. Tissue microarrays were performed using paraffin-embedded tissues (PRA-H n = 53, PRB-H n = 24), and protein expression analyzed by immunohistochemistry. All statistical tests were two-sided.

Results

One hundred sixteen out of 222 (52.3%) PR+ tumors were PRA-H, and 64 (28.8%) PRB-H. Cell proliferation was inhibited by MFP in 19 of 19 tissue cultures from PRA-H tumors. A total of 139 transcripts related to proliferative pathways were differentially expressed in nine PRA-H and seven PRB-H tumors. PRB-H and PRA-H tumors were either luminal B or A phenotypes, respectively ( P = .03). PRB-H cases were associated with shorter relapse-free survival (hazard ratio [HR] = 2.70, 95% confidence interval [CI] = 1.71 to 6.20, P = .02) and distant metastasis-free survival (HR = 4.17, 95% CI = 2.18 to 7.97, P <  .001). PRB-H tumors showed increased tumor size ( P <  .001), Ki-67 levels ( P <  .001), human epidermal growth factor receptor 2 expression ( P =  .04), high grades ( P =  .03), and decreased total PR ( P =  .004) compared with PRA-H tumors. MUC-2 ( P <  .001) and KRT6A ( P =  .02) were also overexpressed in PRB-H tumors.

Conclusion

The PRA/PRB ratio is a prognostic and predictive factor for antiprogestin responsiveness in breast cancer.