Efficacy and Safety of Tinzaparin Thromboprophylaxis in Lung Cancer Patients with High Thromboembolic Risk: A Prospective, Observational, Single-Center Cohort Study

BACKGROUND

The aim of this study was to record and assess the efficacy and safety ofthromboprophylaxis with an intermediate dose of Tinzaparin in lung cancer patients with high thrombotic risk.

METHODS

This was a non-interventional, single-arm, prospective cohort study of lung cancer patients who received thromboprophylaxis with Tinzaparin 10.000 Anti-Xa IU in 0.5 mL, OD, used in current clinical practice. Enrolled ambulatory patients signed informed consent. Anti-Xa levels were tested.

RESULTS

In total, 140 patients were included in the study, of which 81.4% were males. The histology of the tumor was mainly adenocarcinoma. Lung cancer patients with high thrombotic risk based on tumor, patient, treatment, and laboratory-related factors were enrolled. Only one patient experienced a thrombotic event (0.7%), and 10 patients had bleeding events (7.1%), including only one major event. Anti-Xa levels measured at 10 days and 3 months did not differ significantly between patients who developed hemorrhagic events and those who did not (p = 0.26 and p = 0.32, respectively).

CONCLUSION

Thromboprophylaxis with an intermediate Tinzaparin dose in high thrombotic-risk lung cancer patients is a safe and effective choice for the prevention of VTE.

Eligibility for screening with low-dose CT in a real-world cohort of patients with lung cancer in Greece: A brief report

INTRODUCTION

NELSON and NLST prompted the implementation of lung cancer screening programs in the United States followed by several European countries. This study aimed to assess the sensitivity of different screening criteria among patients with lung cancer in Greece and investigate reasons for ineligibility.

METHODS

We performed a retrospective analysis on patients with lung cancer referred to the largest referral center in Athens, Greece, between June 2014 and May 2023. The proportion of patients who would meet the updated USPSTF and NLST criteria was compared to the corresponding proportion of the Greek population over 15 years of age.

RESULTS

Out of 2434 patients with lung cancer, 77.4 % (N = 1883) would meet the updated USPSTF criteria, and 58.9 % (N = 1439) would meet the NLST criteria at diagnosis; the corresponding proportions for the Greek population over 15 years would be 13.8 % and 8.2 %, respectively. Ineligible patients were more likely to be female, former or never-smokers, have adenocarcinoma histology, and have driver mutations (p < 0.001).

CONCLUSIONS

Although the updated USPSTF criteria demonstrated good sensitivity, a substantial proportion of patients with lung cancer would still not be eligible for screening. Future studies to shape a comprehensive screening strategy should focus on the incorporation of additional risk factors for lung cancer, including air pollution and individual genetic susceptibility.

Nivolumab and ipilimumab in combination with radiotherapy in patients with high-risk locally advanced squamous cell carcinoma of the head and neck

BACKGROUND

The combination of nivolumab and ipilimumab has been approved for the treatment of multiple solid tumors. This was a phase I study investigating definitive radioimmunotherapy (RIT) with nivolumab and ipilimumab for the treatment of locally advanced (LA) squamous cell carcinoma of the head and neck (SCCHN).

METHODS

Patients with newly diagnosed, stage IVA-IVB SCCHN eligible for cisplatin-based chemotherapy received nivolumab (3 mg/kg every 2 weeks for a total of 17 doses) and ipilimumab (1 mg/kg every 6 weeks for a total of 6 doses) starting 2 weeks prior to radiotherapy. The primary endpoint was safety of definitive RIT. Secondary endpoints included progression-free survival (PFS) and overall survival (OS). Exploratory endpoints included the association of baseline programmed death-ligand 1 (PD-L1) expression as well as on-treatment changes in immune bias with treatment outcomes.

RESULTS

Twenty-four patients were enrolled. With a median follow-up of 36.1 months, grade 3 or higher treatment-related adverse events were reported in 21 individuals (88%); 5 individuals developed in-field soft tissue ulceration during consolidation immunotherapy, resulting in one fatality. The 3-year PFS and OS rates were 74% (95% CI 58% to 94%) and 96% (95% CI 88% to 100%), respectively. PD-L1 combined positive score (CPS) did not correlate with death or disease progression. Decreases in extracellular vesicle PD-L1 within the concurrent RIT phase were associated with prolonged PFS (p=0.006). Also, interval decreases in circulating interleukin (IL)4, IL9, IL12, and IL17a during concurrent RIT were associated with subsequent ulceration.

CONCLUSIONS

Definitive RIT with nivolumab and ipilimumab has sufficient clinical activity to support further development. Early changes in circulating biomarkers appear able to predict treatment outcomes as well as ensuing in-field soft tissue ulceration.

TRIAL REGISTRATION NUMBER

NCT03162731.

Takotsubo Cardiomyopathy in Cancer Patients Treated with Immune Checkpoint Inhibitors: A Systematic Review and Meta-Summary of Included Cases

BACKGROUND

There are emerging reports of Takotsubo syndrome (TTS) in cancer patients treated with immune checkpoint inhibitors (ICIs); however, the association of the two remains uncertain.

METHODS

A systematic literature review was performed in the PubMed database and web sources (Google Scholar) according to the Preferred Reporting Items for Systematic reviews and Meta-analyses (PRISMA) guidelines. Case reports/series or studies including cancer patients treated with ICIs and presenting with TTS were considered.

RESULTS

Seventeen cases were included in the systematic review. Most patients were males (59%) with median age of 70 years (30-83). Most common tumor types were lung cancer (35%) and melanoma (29%). Most patients were on first-line immunotherapy (35%) and after the first cycle (54%) of treatment. The median time on immunotherapy at the time of TTS presentation was 77 days (1-450). The most used agents were pembrolizumab and the combination of nivolumab-ipilimumab (35%, respectively). Potential stressors were recognized in 12 cases (80%). Six patients (35%) presented with concurrent cardiac complications. Corticosteroids were used in the management of eight patients (50%). Fifteen patients (88%) recovered from TTS, two patients (12%) relapsed, and one patient died. Immunotherapy was reintroduced in five cases (50%).

CONCLUSION

TTS may be associated with immunotherapy for cancer. Physicians should be alert for TTS diagnosis in any patient with myocardial infarction-like presentation under treatment with ICIs.

Quantitative, Spatially Defined Expression of Leukocyte-associated Immunoglobulin-like Receptor in Non-small Cell Lung Cancer

Targeting the interaction of leukocyte-associated immunoglobulin-like receptor-1 (LAIR-1) and its ligands has been shown to reinstate antitumor immunity. In addition, the introduction of the LAIR-1 decoy protein, LAIR-2, sensitizes previously resistant lung tumors to programmed death-1 (PD-1) blockade, indicating the potential of LAIR-1 as an alternative marker for anti-PD-1 resistance in lung cancer. Here, we assessed LAIR-1 as compared with programmed death-ligand 1 (PD-L1) expression in various tumors, with a focus on non-small cell lung cancer (NSCLC) and its histologic subtypes using multiplexed quantitative immunofluorescence (mQIF) in 287 (discovery cohort) and 144 (validation cohort) patients with NSCLC. In addition, using multispectral imaging technology on mQIF images, we evaluated the localization of LAIR-1 on various cell types. We observed that CD14⁺, CD68⁺, and CD163⁺ monocytes and CK⁺ tumor cells predominantly expressed LAIR-1 more than other cell types. Furthermore, LAIR-1 expression in the tumor compartment was significantly higher in patients with lung adenocarcinoma (LUAD) than those with lung squamous cell carcinoma subtype (**, P = 0.003). Our results indicated that high tumor LAIR-1 expression in patients with LUAD is negatively associated with OS (overall survival, HR = 2.4; *, P = 0.02) highlighting its prognostic value in LUAD but not in other subtypes. The Pearson correlation between LAIR-1 and PD-L1 is 0.31; however, mutual exclusive staining pattern (i.e., several cases were positive for LAIR-1 and negative for PD-L1) was observed. Altogether, our data suggest that the combination therapy of anti-PD-1/PD-L1 with anti-LAIR-1 or the anti-LAIR-1 monotherapy alone may be promising cancer immunotherapeutic strategies.

Significance

The spatial, quantitative assessment of LAIR-1 in NSCLC shows positive association of OS with high LAIR-1⁺/CD68⁺ cell densities and negative association of OS with high LAIR-1 expression in LUAD tumor subtype.

Evolving Treatment Landscape of HER2-mutant Non-Small Cell Lung Cancer: Trastuzumab Deruxtecan and Beyond

Successful targeting of HER2-activating mutations in DESTINY-Lung02 phase II study has led to the approval of the antibody-drug conjugate (ADC) trastuzumab deruxtecan (T-DXd) as second-line treatment in patients with non-small cell lung cancer (NSCLC). Despite the impressive results, several matters need to be addressed, including the clinical activity of T-DXd in patients with disease in the central nervous system as well as the role of T-DXd in the context of HER2 overexpression. Additionally, data regarding novel agents used to target HER2 continue to accumulate. This review highlights the challenges and unanswered questions that have emerged after the approval of T-DXd in patients with HER2-mutant NSCLC.

Baseline gene expression profiling determines long-term benefit to programmed cell death protein 1 axis blockade

Treatment with immune checkpoint inhibitors has altered the course of malignant melanoma, with approximately half of the patients with advanced disease surviving for more than 5 years after diagnosis. Currently, there are no biomarker methods for predicting outcome from immunotherapy. Here, we obtained transcriptomic information from a total of 105 baseline tumor samples comprising two cohorts of patients with advanced melanoma treated with programmed cell death protein 1 (PD-1)-based immunotherapies. Gene expression profiles were correlated with progression-free survival (PFS) within consecutive clinical benefit intervals (i.e., 6, 12, 18, and 24 months). Elastic net binomial regression models with cross validation were utilized to compare the predictive value of distinct genes across time. Lasso regression was used to generate a signature predicting long-term benefit (LTB), defined as patients who remain alive and free of disease progression at 24 months post treatment initiation. We show that baseline gene expression profiles were consistently able to predict long-term immunotherapy outcomes with high accuracy. The predictive value of different genes fluctuated across consecutive clinical benefit intervals, with a distinct set of genes defining benefit at 24 months compared to earlier outcomes. A 12-gene signature was able to predict LTB following anti-PD-1 therapy with an area under the curve (AUC) equal to 0.92 and 0.74 in the training and validation set, respectively. Evaluation of LTB, via a unique signature may complement objective response classification and characterize the logistics of sustained antitumor immune responses.

Programmed Cell Death Protein 1 Axis Inhibition in Viral Infections: Clinical Data and Therapeutic Opportunities

A vital function of the immune system is the modulation of an evolving immune response. It is responsible for guarding against a wide variety of pathogens as well as the establishment of memory responses to some future hostile encounters. Simultaneously, it maintains self-tolerance and minimizes collateral tissue damage at sites of inflammation. In recent years, the regulation of T-cell responses to foreign or self-protein antigens and maintenance of balance between T-cell subsets have been linked to a distinct class of cell surface and extracellular components, the immune checkpoint molecules. The fact that both cancer and viral infections exploit similar, if not the same, immune checkpoint molecules to escape the host immune response highlights the need to study the impact of immune checkpoint blockade on viral infections. More importantly, the process through which immune checkpoint blockade completely changed the way we approach cancer could be the key to decipher the potential role of immunotherapy in the therapeutic algorithm of viral infections. This review focuses on the effect of programmed cell death protein 1/programmed death-ligand 1 blockade on the outcome of viral infections in cancer patients as well as the potential benefit from the incorporation of immune checkpoint inhibitors (ICIs) in treatment of viral infections.

Quantitative assessment of Siglec-15 expression in lung, breast, head, and neck squamous cell carcinoma and bladder cancer

Immune checkpoint blockade with programmed cell death (PD-1)/programmed death-ligand 1 (PD-L1) inhibitors has resulted in significant progress in the treatment of various cancer types. However, not all patients respond to PD-1/PD-L1 blockade, underscoring the importance of identifying new potential targets for immunotherapy. One promising target is the immune system modulator Siglec-15. In this study, we assess Siglec-15 expression in solid tumors, with a focus on lung, breast, head and neck squamous and bladder cancers. Using quantitative immunofluorescence (QIF) with a previously validated antibody, we found increased Siglec-15 expression in both tumor and immune cells in all the four cancer types. Siglec-15 was seen to be predominantly expressed by the stromal immune cells (83% in lung, 70.1% in breast, 95.2% in head and neck squamous cell and 89% in bladder cancers). Considerable intra-tumoral heterogeneity was noted across cancer types. As previously described for non-small cell lung cancer (NSCLC), Siglec-15 expression was seen to be mutually exclusive to PD-L1 in all the four cancer types, although this differential expression was maintained but somewhat diminished in head and neck squamous cell carcinoma (HNSCC). Siglec-15 was not prognostic either for overall survival (OS) or progression-free survival (PFS). In summary, we show broad expression of this potential immune modulatory target in a wide range of cancer types. These data suggest potential future clinical trials in these tumor types.

New Insights into SARS-CoV-2 and Cancer Cross-Talk: Does a Novel Oncogenesis Driver Emerge?

Since the pandemic’s onset, a growing population of individuals has recovered from SARS-CoV-2 infection and its long-term effects in some of the convalescents are gradually being reported. Although the precise etiopathogenesis of post-acute COVID-19 sequelae (PACS) remains elusive, the mainly accepted rationale is that SARS-CoV-2 exerts long-lasting immunomodulatory effects, promotes chronic low-grade inflammation, and causes irreversible tissue damage. So far, several viruses have been causally linked to human oncogenesis, whereas chronic inflammation and immune escape are thought to be the leading oncogenic mechanisms. Excessive cytokine release, impaired T-cell responses, aberrant activation of regulatory signaling pathways (e.g., JAK-STAT, MAPK, NF-kB), and tissue damage, hallmarks of COVID-19 disease course, are also present in the tumor microenvironment. Therefore, the intersection of COVID-19 and cancer is partially recognized and the long-term effects of the virus on oncogenesis and cancer progression have not been explored yet. Herein, we present an up-to-date review of the current literature regarding COVID-19 and cancer cross-talk, as well as the oncogenic pathways stimulated by SARS-CoV-2.

Spatially resolved proteomic profiling identifies tumor cell CD44 as a biomarker associated with sensitivity to PD-1 axis blockade in advanced non-small-cell lung cancer

BACKGROUND

Most patients with advanced non-small-cell lung cancer (NSCLC) fail to derive significant benefit from programmed cell death protein-1 (PD-1) axis blockade, and new biomarkers of response are needed. In this study, we aimed to discover and validate spatially resolved protein markers associated with sensitivity to PD-1 axis inhibition in NSCLC.

METHODS

We initially assessed a discovery cohort of 56 patients with NSCLC treated with PD-1 axis inhibitors at Yale Cancer Center. Using the GeoMx Digital Spatial Profiling (DSP) system, 71 proteins were measured in spatial context on each spot in a tissue microarray. We used the AQUA method of quantitative immunofluorescence (QIF) to orthogonally validate candidate biomarkers. For external independent validation, we assessed whole tissue sections derived from 128 patients with NSCLC treated with single-agent PD-1 axis inhibitors at the 12 de Octubre Hospital (Madrid) using DSP. We further analyzed two immunotherapy untreated cohorts to address prognostic significance (n=252 from Yale Cancer Center; n=124 from University Clinic of Navarra) using QIF and DSP, respectively.

RESULTS

Using continuous log-scaled data, we identified CD44 expression in the tumor compartment (pan-cytokeratin (CK)+) as a novel predictor of prolonged progression-free survival (PFS) (multivariate HR=0.68, p=0.043) in the discovery set. We validated by QIF that tumor CD44 levels assessed as continuous QIF scores were associated with longer PFS (multivariate HR=0.31, p=0.022) and overall survival (multivariate HR=0.29, p=0.038). Using DSP in an independent immunotherapy treated cohort, we validated that CD44 levels in the tumor compartment, but not in the immune compartment (panCK-/CD45+), were associated with clinical benefit (OR=1.22, p=0.018) and extended PFS under PD-1 axis inhibition using the highest tertile cutpoint (multivariate HR=0.62, p=0.03). The effect of tumor cell CD44 in predicting PFS remained significant after correcting for programmed death-ligand 1 (PD-L1) Tumor Proportion Score (TPS) in both cohorts. High tumor cell CD44 was not prognostic in the absence of immunotherapy. Using DSP data, intratumoral regions with elevated tumor cell CD44 expression showed prominent (fold change>1.5, adjusted p<0.05) upregulation of PD-L1, TIM-3, ICOS, and CD40 in two independent cohorts.

CONCLUSIONS

This work highlights CD44 as a novel indicative biomarker of sensitivity to PD-1 axis blockade that might help to improve immunotherapy strategies for NSCLC.

CD24: A Novel Target for Cancer Immunotherapy

Cluster of differentiation 24 (CD24) is a small, highly glycosylated cell adhesion protein that is normally expressed by immune as well as epithelial, neural, and muscle cells. Tumor CD24 expression has been linked with alterations in several oncogenic signaling pathways. In addition, the CD24/Siglec-10 interaction has been implicated in tumor immune evasion, inhibiting macrophage-mediated phagocytosis as well as natural killer (NK) cell cytotoxicity. CD24 blockade has shown promising results in preclinical studies. Although there are limited data on efficacy, monoclonal antibodies against CD24 have demonstrated clinical safety and tolerability in two clinical trials. Other treatment modalities evaluated in the preclinical setting include antibody–drug conjugates and chimeric antigen receptor (CAR) T cell therapy. In this review, we summarize current evidence and future perspectives on CD24 as a potential target for cancer immunotherapy.

Programmed cell death protein 1 axis blockade in locally advanced squamous cell carcinoma of the head and neck: Neoadjuvant and adjuvant approaches

Immunotherapy and in particular programmed cell death protein 1 (PD-1) inhibitors have been applied not only in the management of recurrent or metastatic disease but also as component of potentially curative treatment for many solid tumors. The incorporation of immunotherapy as neoadjuvant and /or adjuvant therapy in the treatment paradigm of locally advanced squamous cell carcinoma of the head and neck (SCCHN) is appealing with the goals of enhancing antitumor efficacy and, at the same time, reduce toxicity. This review analyzes the rationale for employing immunotherapy in the neoadjuvant and adjuvant settings, reviews the results of relevant clinical trials, and examines the potential benefits and caveats of neoadjuvant and/or adjuvant approaches in patients with SCCHN.

Immune Checkpoint Blockade in Hormone Receptor-Positive Breast Cancer: Resistance Mechanisms and Future Perspectives

Anti-programmed cell death protein 1 immunotherapy has been incorporated in the treatment algorithm of triple-negative breast cancer (TNBC). However, clinical trial results for patients with hormone receptor (HR)-positive disease appear less compelling. HR-positive tumors exhibit lower levels of programmed death-ligand 1 expression in comparison with their triple-negative counterparts. Moreover, signaling through estrogen receptor alters the immune microenvironment, rendering such tumors immunologically "cold." To explain differential responses to immune checkpoint blockade, this review interrogates differences between HR-positive and TNBC. Starting from distinct genomic features, we further present disparities concerning the tumor microenvironment and finally, we summarize early-phase clinical trial results on promising novel immunotherapy combinations.

PD-L1 and PD-L2 mRNA measured using closed system qRT-PCR are associated with outcome and high negative predictive value in immunotherapy-treated non-small cell lung cancer

INTRODUCTION

Immune checkpoint inhibitors (ICIs) have become standard of care in lung cancer management, but only a relatively small percentage of patients treated respond. Current predictive biomarkers, including immunohistochemical (IHC) detection of PD-L1, are insufficient for determining who will respond or, more importantly in the adjuvant setting, who will not respond to ICI therapy. Here, we investigate an alternative method of assessment of PD-L1 to predict non-response.

METHODS

This study utilizes a research use only quantitative real-time reverse transcription polymerase chain reaction assay on the GeneXpert® (GX) system, to test for the association between 4 target immune genes, CD274 (PD-L1), PDCD1LG2 (PD-L2), CD8A, and IRF1, and response to ICI therapy. Tissues were collected from 122 patients with advanced non-small cell lung cancer prior to ICI therapy in a retrospective cohort, macro-dissected, and analyzed using the GX.

RESULTS

Both high PD-L1 and PD-L2 mRNA expression levels were associated with improved long-term benefit at 24 months (p=0.047 for both PD-L1 and PD-L2) and overall survival (PD-L1, p= 0.048; PD-L2 p= 0.049). Both PD-L1 and PD-L2 mRNA levels were higher in patients with KRAS mutations. Most importantly, low PD-L1 mRNA showed a high negative predictive value of 0.92 for absence of long-term benefit.

CONCLUSIONS

With further validation this assay in low stage patients, assessment of PD-L1 mRNA rather than protein, could be a method to determine which low stage patients should not be treated with ICIs in the adjuvant setting. This approach may also be a useful objective method for selecting patients for treatment in the advanced setting.

Quantitative assessment of the immune microenvironment in African American Triple Negative Breast Cancer: a case-control study

PURPOSE

Triple negative breast cancer (TNBC) is more common in African American (AA) than Non-AA (NAA) population. We hypothesize that tumor microenvironment (TME) contributes to this disparity. Here, we use multiplex quantitative immunofluorescence to characterize the expression of immunologic biomarkers in the TME in both populations.

PATIENTS AND METHODS

TNBC tumor resection specimen tissues from a 100-patient case: control cohort including 49 AA and 51 NAA were collected. TME markers including CD45, CD14, CD68, CD206, CD4, CD8, CD20, CD3, Ki67, GzB, Thy1, FAP, aSMA, CD34, Col4, VWF and PD-L1 we quantitatively assessed in every field of view. Mean expression levels were compared between cases and controls.

RESULTS

Although no significant differences were detected in individual lymphoid and myeloid markers, we found that infiltration with CD45⁺ immune cells (p = 0.0102) was higher in TNBC in AA population. AA TNBC tumors also had significantly higher level of lymphocytic infiltration defined as CD45⁺ CD14^- cells (p = 0.0081). CD3⁺ T-cells in AA tumors expressed significantly higher levels of Ki67 (0.0066) compared to NAAs, indicating that a higher percentage of AA tumors contained activated T-cells. All other biomarkers showed no significant differences between the AA and NAA group.

CONCLUSIONS

While the TME in TNBC is rich in immune cells in both racial groups, there is a numerical increase in lymphoid infiltration in AA compared to NAA TNBC. Significantly, higher activated T cells seen in AA patients raises the possibility that there may be a subset of AA patients with improved response to immunotherapy.

HER2 Aberrations in Non-Small Cell Lung Cancer: From Pathophysiology to Targeted Therapy

While human epidermal growth factor receptor 2 (HER2) aberrations have long been described in patients with non-small cell lung cancer (NSCLC), they have only recently been effectively targeted. Unlike patients with breast cancer, NSCLC patients can harbor either HER2-activating mutations or HER2 amplification coupled with protein overexpression. The latter has also been the case for patients with acquired resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs). As preclinical data continue to accumulate, clinical trials evaluating novel agents that target HER2 have produced promising preliminary results. Here, we review existing data on HER2 aberrations in NSCLC. Starting from HER2 biology in normal and disease processes, we summarize discrepancies in HER2 diagnostic assays between breast cancer and NSCLC. Finally, to dissect the therapeutic implications of HER2-activating mutations versus gene amplification and/or protein overexpression, we present data from prospective clinical trials that have employed distinct classes of agents to target HER2 in patients with NSCLC.

Alpha-smooth Muscle Actin Expression in the Stroma Predicts Resistance to Trastuzumab in Patients with Early-stage HER2-positive Breast Cancer

PURPOSE

The companion diagnostic test for trastuzumab has not changed much in the last 25 years. We used high-plex digital spatial profiling to identify biomarkers besides HER2 that can help predict response to trastuzumab in HER2-positive breast cancer.

EXPERIMENTAL DESIGN

Fifty-eight protein targets were measured in three different molecularly defined compartments by the NanoString GeoMx Digital Spatial Profiler (DSP) in a tissue microarray containing 151 patients with breast cancer that received adjuvant trastuzumab as part of the Hellenic Cooperative Oncology Group 10/05 clinical trial. Promising candidate biomarkers were orthogonally validated with quantitative immunofluorescence (QIF). RNA-sequencing data from the Neoadjuvant Lapatinib and/or Trastuzumab Treatment Optimisation Study (NeoALTTO) were accessed to provide independent cohort validation. Disease-free survival (DFS) was the main outcome assessed. Statistical analyses were performed using a two-sided test (α = 0.05) and multiple testing correction (Benjamini-Hochberg method, FDR < 0.1).

RESULTS

By DSP, high expression of alpha-smooth muscle actin (α-SMA), both in the leukocyte and stromal compartments, was associated with shorter DFS in univariate analysis (P = 0.002 and P = 0.023, respectively). High α-SMA expression in the stroma was validated by QIF after controlling for estrogen receptor and progesterone receptor status [HR, 3.12; 95% confidence interval (CI), 1.12-8.68; P = 0.029] showing recurrence on trastuzumab in the same cohort. In the NeoALTTO cohort, elevated levels of ACTA2 were predictive for shorter DFS in the multivariate analysis (HR, 3.21; 95% CI, 1.14-9.05; P = 0.027).

CONCLUSIONS

This work identifies α-SMA as a novel, easy-to-implement biomarker of resistance to trastuzumab that may be valuable in settings where trastuzumab is combined with other therapies.

Targeting Pyruvate Kinase M2 Phosphorylation Reverses Aggressive Cancer Phenotypes

Triple-negative breast cancer (TNBC) is the most aggressive breast cancer subtype with low survival rate and a lack of biomarkers and targeted treatments. Here, we target pyruvate kinase M2 (PKM2), a key metabolic component of oncogenesis. In patients with TNBC, PKM2pS37 was identified as a prominent phosphoprotein corresponding to the aggressive breast cancer phenotype that showed a characteristic nuclear staining pattern and prognostic value. Phosphorylation of PKM2 at S37 was connected with a cyclin-dependent kinase (CDK) pathway in TNBC cells. In parallel, pyruvate kinase activator TEPP-46 bound PKM2pS37 and reduced its nuclear localization. In a TNBC mouse xenograft model, treatment with either TEPP-46 or the potent CDK inhibitor dinaciclib reduced tumor growth and diminished PKM2pS37. Combinations of dinaciclib with TEPP-46 reduced cell invasion, impaired redox balance, and triggered cancer cell death. Collectively, these data support an approach to identify PKM2pS37-positive TNBC and target the PKM2 regulatory axis as a potential treatment. SIGNIFICANCE: PKM2 phosphorylation marks aggressive breast cancer cell phenotypes and targeting PKM2pS37 could be an effective therapeutic approach for treating triple-negative breast cancer.

Abstract 339: Resistance to trastuzumab is associated with alpha-smooth muscle actin expression in the stroma of patients with HER2+ breast cancer

Background: Approximately 15-20% of women diagnosed with breast cancer have HER2+ disease. Trastuzumab is currently FDA approved for the treatment of HER+ breast cancer, based on assessment of HER2 status by the combination of IHC and FISH assays. We hypothesized that there are biomarkers besides HER2 that can help predict response, or resistance, to trastuzumab in HER2+ breast cancer.

Methods: We used the NanoString® GeoMx® Digital Spatial Profiler (DSP) to measure 58 protein targets in three different enriched compartments (tumor [PanCK+], leukocyte [CD45+/CD68-] and macrophage [CD68+]) in a cohort of 151 breast cancer patients that received trastuzumab in the adjuvant setting, represented in a tissue microarray. To assess stromal protein expression, leukocyte and macrophage compartments were analyzed in aggregate. Spatially-resolved proteins were correlated with disease-free survival (DFS). Then, we used multiplexed quantitative immunofluorescence (QIF), performed on the AQUA platform, to validate our findings. Statistical analyses were performed using a two-sided test (α=0.05) and multiple testing correction (Benjamini-Hochberg method, FDR&lt;0.10).

Results: We assessed 58 individual protein targets in four compartments resulting in 282 candidate biomarkers per patient. After adjusting for multiple testing, high expression of alpha-smooth muscle actin (a-SMA) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), both measured in the leukocyte compartment, were associated with shorter DFS in univariate analysis (p=0.045 and p=0.084, respectively); high expression of a-SMA in the stroma was also associated with worse outcome (HR, 4.94; 95% CI, 1.07-22.86; unadjusted p=0.023). Digital counts of a-SMA were inversely correlated with immune cell infiltration in the stroma. Using QIF, and after adjusting for four clinical prognostic factors (stage, grade, ER status and PR status), we validated that high a-SMA expression in the stroma was predictive for shorter DFS (HR, 3.34; 95% CI, 1.18-9.48, p=0.023) in the same cohort.

Conclusions: This work supports the role of cancer-associated fibroblasts in the tumor microenvironment in orchestrating the immune response and mediating resistance to trastuzumab for patients with HER2+ breast cancer. In light of the many new HER2 targeted therapies, this observation identifies a-SMA as a potential biomarker to augment the predictive value of the current standard of care HER2 assay and justifies further validation.

Citation Format: Ioannis A. Vathiotis, Myrto K. Moutafi, Prajan Divakar, Thazin Nwe Aung, Aileen Fernandez, Vesal Yaghoobi, Saba Shafi, Konstantinos N. Syrigos, George Fountzilas, Lajos Pusztai, Sarah Warren, David L. Rimm. Resistance to trastuzumab is associated with alpha-smooth muscle actin expression in the stroma of patients with HER2+ breast cancer [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 339.

Programmed Death-Ligand 1 as a Regulator of Tumor Progression and Metastasis

Programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) immune checkpoint has long been implicated in modeling antitumor immunity; PD-1/PD-L1 axis inhibitors exert their antitumor effects by relieving PD-L1-mediated suppression on tumor-infiltrating T lymphocytes. However, recent studies have unveiled a distinct, tumor-intrinsic, potential role for PD-L1. In this review, we focus on tumor-intrinsic PD-L1 signaling and delve into preclinical evidence linking PD-L1 protein expression with features of epithelial-to-mesenchymal transition program, cancer stemness and known oncogenic pathways. We further summarize data from studies supporting the prognostic significance of PD-L1 in different tumor types. We show that PD-L1 may indeed have oncogenic potential and act as a regulator of tumor progression and metastasis.

Comparison of programmed death-ligand 1 protein expression between primary and metastatic lesions in patients with lung cancer

Assessment of programmed cell death-ligand 1 (PD-L1) expression by immunohistochemistry (IHC) is the definite diagnostic test to guide treatment for patients with advanced-stage non-small cell lung cancer. Intratumoral heterogeneity and discrepancy of PD-L1 expression between primary and metastatic lesions may increase the risk of tumor misclassification. We performed a retrospective study of the Foundation Medicine, Inc clinical database on lung cancer cases that were evaluated for PD-L1 expression by IHC in the context of routine care. All cases were assessed with the Food and Drug Administration-approved 22C3 pharmDx assay and scoring system. 15,028 lung cancer cases, including 8285 primary tumors and 6743 unmatched metastatic lesions were analyzed. Metastatic lesions (mets) were more frequently high positive (tumor proportion score (TPS) ≥50%) for PD-L1 expression than primary lesions (33.8% vs 28.4%; OR, 1.28; 95% CI, 1.19 to 1.37; p<0.001). Higher levels in mets than primaries were seen in samples from lymph nodes, pleural fluid, soft tissue and adrenal gland but not in those from liver, brain and bone. Metastatic lesions of patients with non-squamous histology were more likely to have TPS ≥50% in comparison with primary (OR, 1.37; 95% CI, 1.27 to 1.49; p<0.001), but this was not the case for patients with squamous histology (OR, 0.89; 95% CI, 0.74 to 1.06; p=0.197). PD-L1 expression varies with respect to histologic subtype, sampling site and gender, but is generally higher in metastatic sites. This observation may affect future patient management and trial design.

Enhancing programmed cell death protein 1 axis inhibition in head and neck squamous cell carcinoma: Combination immunotherapy

Anti-programmed cell death protein 1 immunotherapy has become the new standard in the treatment of patients with recurrent or metastatic head and neck squamous cell carcinoma (HNSCC). However, the population that benefits is small, warranting drug combinations and novel approaches. HNSCC is a profoundly immunosuppressive disease, characterized by the interplay among different immune regulatory pathways. As clinical trials evaluating immunotherapy combinations in patients with HNSCC have started producing preliminary results, preclinical evidence on potential new targets for combination immunotherapy continues to accumulate. This review summarizes emerging clinical and preclinical data on immunotherapy combinations for the treatment of HNSCC.

Quantitative Assessment of CD200 and CD200R Expression in Lung Cancer

CD200/CD200R is an immune checkpoint with broad expression patterns and a potential target for immune therapy. In this study, we assess both CD200 and CD200R expression in solid tumors, with a focus on lung cancer, and evaluate their association with clinicopathologic characteristics, mutation status, outcome, and programmed death-ligand 1 (PD-L1) expression. We used multiplexed quantitative immunofluorescence (QIF) to measure the expression of CD200 and CD200R in a total of 455 patients from three lung cancer cohorts. Using carefully validated antibodies, we performed target measurement with tyramide-based QIF panels and analyzed the data using the PM2000 microscope and AQUA software. CD200 tumor positivity was found in 29.7% of non-small cell lung cancer (NSCLC) patients and 33.3% of lung large cell neuroendocrine carcinoma (LCNEC) patients. CD200 demonstrated notable intratumoral heterogeneity. CD200R was expressed in immune cells in 25% of NSCLC and 41.3% of LCNEC patients. While CD200R is predominantly expressed in immune cells, rare tumor cell staining was seen in a highly heterogeneous pattern. CD200R expression in the stromal compartment was significantly higher in patients with squamous differentiation (p < 0.0001). Neither CD200 nor CD200R were associated with other clinicopathologic characteristics or mutation status. Both biomarkers were not prognostic for disease-free or overall survival in NSCLC. CD200 showed moderate correlation with PD-L1. CD200/CD200R pathway is frequently expressed in lung cancer patients. Differential expression patterns of CD200 and CD200R with PD-L1 suggest a potential role for targeting this pathway alone in patients with NSCLC.

Tinzaparin Safety in Patients With Cancer and Renal Impairment: A Systematic Review

Low-molecular-weight heparins are approved for primary and secondary venous thromboembolism prevention. Tinzaparin is the low-molecular-weight heparin with the highest average molecular weight. The purpose of this systematic review is to provide an update regarding the safety profile of tinzaparin, prescribed either as a prophylactic or as a therapeutic regimen for venous thromboembolism in special populations, including cancer patients and patients with renal impairment. We identified prospective studies up to August 2020 reporting safety outcomes for cancer patients and patients with renal impairment on tinzaparin regimens. In patients with cancer major bleeding rates fluctuated between 0.8% and 7%. Patients on tinzaparin exhibited significantly lower rates of clinically relevant nonmajor bleeding events in comparison with those on vitamin K antagonists. Bioaccumulation of tinzaparin was not correlated with age, body weight or creatinine clearance. Periodic administration of either prophylactic or therapeutic doses of tinzaparin did not result in bioaccumulation, even in patients with severe renal impairment and creatinine clearance < 20 ml/min. Major bleeding rates for non-cancer patients with renal impairment on prophylactic tinzaparin regimens were 0%. Non-cancer patients with renal impairment on therapeutic tinzaparin regimens exhibited major bleeding in 0 to 3.4% of cases; major bleeding rates were higher for cancer patients with renal impairment on therapeutic tinzaparin regimens (4.3 to 10%). Tinzaparin can be used without dose adjustment in patients with severe renal impairment and creatinine clearance > 20 ml/min. Tinzaparin represents a safe choice for special populations at increased risk for thrombosis and bleeding.

Antibody validation for protein expression on tissue slides: a protocol for immunohistochemistry

Antibodies play a crucial role in basic research and clinical decision-making. However, there are no standardized algorithms or guidelines to ensure their accuracy and validity. There have been efforts to generate consensus, but, with the exception of clinical labs, antibody validation remains variable in the literature and sometimes in clinical practice. Here we focus on immunohistochemistry, an example of a scientific and clinical tool where validation of antibodies is critical. We describe a protocol that we use to validate antibodies specifically for immunohistochemistry, including some of the pillars of antibody validation from Uhlen et al. 2016, as an example of a rigorous approach to build antibody-based tests for both basic and translational science labs and for the clinic.

Abstract 3095: Combination of spatial protein data with bulk transcriptional profiling of the same cohort shows relationships between RNA and protein and facilitates combined predictive signatures

Background: Although there are several mRNA signatures with some ability to predict outcomes in melanoma patients treated with immunotherapy, more robust predictive models are needed to optimize therapeutic selection. Here, we integrated spatially-resolved protein information acquired by the NanoString® GeoMx® Digital Spatial Profiler (DSP) with information from bulk mRNA gene expression acquired using NanoString® nCounter® PanCancer IO 360™ panel on the same cohort of immunotherapy treated melanoma patients to create predictive models associated with clinical outcomes.

Methods: We assessed pretreatment tumor samples from 59 immunotherapy treated melanoma patients. RNA for gene expression was extracted from formalin-fixed paraffin-embedded whole tissue sections, then hybridized to the 770-plex PanCancer IO 360™ panel and measured on the nCounter platform. The same cases were represented in a tissue microarray, where 32 protein targets were quantified in three different compartments (tumor [s100+], leukocyte [CD45+] and macrophage [CD68+]) using NanoString's GeoMx DSP platform (Toki et al, CCR 2018). The combined dataset of IO 360 gene expression and GeoMx DSP protein data was compared to patient overall survival (OS), objective response (OR), or clinical benefit (CB) using univariate cox or logistic regression models, as well as receiver operator characteristic (ROC) analysis. For each outcome, we used either Lasso (L1 Regularization) or Elastic Net (L0.5 Regularization) approaches to select analytes that were initially identified as nominally significant univariate analysis (P&lt;0.05). Internal leave one out cross-validation was used to ensure model robustness.

Results: Hierarchical clustering of both data sets showed that the DSP data generally clustered away from bulk RNA profiling data. PD-L1 mRNA showed weak correlation with spatially-derived protein (R2=0.04 in the s100+, 0.11 in the CD68+ and 0.12 in the CD45+ compartment). IDO1 mRNA was moderately correlated with protein (R2=0.39 in the s100+, 0.21 in the CD68+ and 0.23 in the CD45+ compartment). A total of 228 variables (including 191 mRNA and 37 protein) that were statistically significant in univariate analysis were identified. Models were constructed to predict OR, OS and CB with individual and mixed modality markers with AUCs above 0.7.

Conclusions: This work supports the integration of spatially-derived protein data with bulk mRNA gene expression data for the construction of predictive models for melanoma patients receiving immune checkpoint inhibition and lays the groundwork for validation in an independent dataset.

Citation Format: Ioannis A. Vathiotis, Jason Reeves, Maria Toki, Pok Fai Wong, Harriet Kluger, Thazin Nwe Aung, Konstantinos N. Syrigos, Sarah Warren, David L. Rimm. Combination of spatial protein data with bulk transcriptional profiling of the same cohort shows relationships between RNA and protein and facilitates combined predictive signatures [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3095.

Abstract 937: Quantitative assessment of CD200 and CD200R expression in lung cancer

Background: CD200 is a membrane-bound glycoprotein expressed on normal tissue, tumor and immune cells. The interaction of CD200 with its receptor leads to attenuation of the inflammatory process, resulting in tumor cell mediated immune suppression. CD200 has been characterized in hematologic malignancies and consists of an independent negative prognostic factor for chronic lymphocytic leukemia, acute myeloid leukemia and multiple myeloma patients. Here we assess both CD200 and CD200R expression in lung cancer and evaluate its association with clinicopathologic characteristics, mutation status, outcome and PD-L1 expression.

Methods: We used quantitative multiplexed immunofluorescence (QIF) to measure the expression of CD200 and CD200R in 287 non-small cell lung cancer (NSCLC) patients and 30 patients with large cell neuroendocrine carcinomas (LCNEC) of the lung. We performed target measurement with tyramide-based QIF panels and analyzed the data using the PM2000 microscope and AQUA software. Targets were measured in cytokeratin-positive (CK+) tumor compartment and cytokeratin-negative (CK-) stromal compartment.

Results: CD200 tumor positivity was found in 29.7% of NSCLC patients and 33.3% of LCNEC patients. CD200 demonstrated notable intratumoral heterogeneity (R2=0.09-0.31 between different TMA blocks versus 0.46-0.60 for CD200R). CD200R was expressed in immune cells in 25% of NSCLC and 41.3% of LCNEC patients. While CD200R is predominantly expressed in immune cells, rare tumor cell staining was seen in a highly heterogeneous pattern. CD200R expression in the stromal compartment was significantly higher in patients with squamous differentiation (p&lt;0.0001). Neither CD200 nor CD200R were associated with other clinicopathologic characteristics or mutation status. Both CD200 and CD200R were not prognostic for disease-free or overall survival in NSCLC. Since these biomarkers are associated with immune modulation, both markers were assessed for correlation with PD-L1. CD200 showed moderate correlation with PD-L1 (R2=0.28 in the CK+ compartment and 0.40 in the CK- compartment); CD200R was less correlated with PD-L1 (R2=0.07 in the CK+ compartment and 0.10 in the CK- compartment).

Conclusions: CD200 and CD200R pathway represents a novel immune checkpoint, frequently expressed in lung cancer patients. Co-expression patterns of CD200 and CD200R with PD-L1 suggest a potential role for targeting this pathway alone or in combination with PD-1/PD-L1 axis inhibitors.

Citation Format: Ioannis A. Vathiotis, Tyler MacNeil, Jon Zugazagoitia, Sandra Martinez-Morilla, Fahad Ahmed, Konstantinos N. Syrigos, Aaron M. Gruver, Kyla Driscoll, David L. Rimm. Quantitative assessment of CD200 and CD200R expression in lung cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 937.