Personalizing NSCLC therapy by characterizing tumors using TKI-PET and immuno-PET

Molecular imaging for evaluation of synovitis associated with osteoarthritis: a narrative review

Recent evidence highlights the role of low-grade synovial inflammation in the progression of osteoarthritis (OA). Inflamed synovium of OA joints detected by imaging modalities are associated with subsequent progression of OA. In this sense, detecting and quantifying synovitis of OA by imaging modalities may be valuable in predicting OA progressors as well as in improving our understanding of OA progression. Of the several imaging modalities, molecular imaging such as positron emission tomography (PET) and single-photon emission computed tomography (SPECT) has an advantage of visualizing the cellular or subcellular events of the tissues. Depending on the radiotracers used, molecular imaging method can potentially detect and visualize various aspects of synovial inflammation. This narrative review summarizes the recent progresses of imaging modalities in assessing inflammation and OA synovitis and focuses on novel radiotracers. Recent studies about imaging modalities including ultrasonography (US), magnetic resonance imaging (MRI), and molecular imaging that were used to detect and quantify inflammation and OA synovitis are summarized. Novel radiotracers specifically targeting the components of inflammation have been developed. These tracers may show promise in detecting inflamed synovium of OA and help in expanding our understanding of OA progression.

Radiolabeled EGFR TKI as predictive imaging biomarkers in NSCLC patients – an overview

Non-small cell lung cancer (NSCLC) has one of the highest cancer-related mortality rates worldwide. In a subgroup of NSCLC, tumor growth is driven by epidermal growth factor receptors (EGFR) that harbor an activating mutation. These patients are best treated with EGFR tyrosine kinase inhibitors (EGFR TKI). Identifying the EGFR mutational status on a tumor biopsy or a liquid biopsy using tumor DNA sequencing techniques is the current approach to predict tumor response on EGFR TKI therapy. However, due to difficulty in reaching tumor sites, and varying inter- and intralesional tumor heterogeneity, biopsies are not always possible or representative of all tumor lesions, highlighting the need for alternative biomarkers that predict tumor response. Positron emission tomography (PET) studies using EGFR TKI-based tracers have shown that EGFR mutational status could be identified, and that tracer uptake could potentially be used as a biomarker for tumor response. However, despite their likely predictive and monitoring value, the EGFR TKI-PET biomarkers are not yet qualified to be used in the routine clinical practice. In this review, we will discuss the currently investigated EGFR-directed PET biomarkers, elaborate on the typical biomarker development process, and describe how the advances, challenges, and opportunities of EGFR PET biomarkers relate to this process on their way to qualification for routine clinical practice.

Positron emission tomography imaging of lung cancer: An overview of alternative positron emission tomography tracers beyond F18 fluorodeoxyglucose

Lung cancer has been the leading cause of cancer-related mortality in China in recent decades. Positron emission tomography-computer tomography (PET/CT) has been established in the diagnosis of lung cancer. ¹⁸F-FDG is the most widely used PET tracer in foci diagnosis, tumor staging, treatment planning, and prognosis assessment by monitoring abnormally exuberant glucose metabolism in tumors. However, with the increasing knowledge on tumor heterogeneity and biological characteristics in lung cancer, a variety of novel radiotracers beyond ¹⁸F-FDG for PET imaging have been developed. For example, PET tracers that target cellular proliferation, amino acid metabolism and transportation, tumor hypoxia, angiogenesis, pulmonary NETs and other targets, such as tyrosine kinases and cancer-associated fibroblasts, have been reported, evaluated in animal models or under clinical investigations in recent years and play increasing roles in lung cancer diagnosis. Thus, we perform a comprehensive literature review of the radiopharmaceuticals and recent progress in PET tracers for the study of lung cancer biological characteristics beyond glucose metabolism.

PET Imaging of Lung Cancers in Precision Medicine: Current Landscape and Future Perspective

Despite the recent advances in cancer treatment, lung cancer remains the leading cause of cancer mortality worldwide. Immunotherapies using immune checkpoint inhibitors (ICIs) achieved substantial efficacy in nonsmall cell lung cancer (NSCLC). Currently, most ICIs are still a monoclonal antibody (mAb). Using mAbs or antibody derivatives labeled with radionuclide as the tracers, immunopositron emission tomography (immunoPET) possesses multiple advantages over traditional ¹⁸F-FDG PET in imaging lung cancers. ImmunoPET presents excellent potential in detecting, diagnosing, staging, risk stratification, treatment guidance, and recurrence monitoring of lung cancers. By using radiolabeled mAbs, immunoPET can visualize the biodistribution and uptake of ICIs, providing a noninvasive modality for patient stratification and response evaluation. Some novel targets and associated tracers for immunoPET have been discovered and investigated. This Review introduces the value of immunoPET in imaging lung cancers by summarizing both preclinical and clinical evidence. We also emphasize the value of immunoPET in optimizing immunotherapy in NSCLC. Lastly, immunoPET probes developed for imaging small cell lung cancer (SCLC) will also be discussed. Although the major focus is to summarize the immunoPET tracers for lung cancers, we also highlighted several small-molecule PET tracers to give readers a balanced view of the development status.

Physiologically Based Pharmacokinetic (PBPK) Modeling to Predict PET Image Quality of Three Generations EGFR TKI in Advanced-Stage NSCLC Patients

Introduction: Epidermal growth factor receptor (EGFR) mutated NSCLC is best treated using an EGFR tyrosine kinase inhibitor (TKI). The presence and accessibility of EGFR overexpression and mutation in NSCLC can be determined using radiolabeled EGFR TKI PET/CT. However, recent research has shown a significant difference between image qualities (i.e., tumor-to-lung contrast) in three generation EGFR TKIs: ¹¹C-erlotinib, ¹⁸F-afatinib and ¹¹C-osimertinib. In this research we aim to develop a physiological pharmacokinetic (PBPK)-model to predict tumor-to-lung contrast and as a secondary outcome the uptake of healthy tissue of the three tracers. Methods: Relevant physicochemical and drug specific properties (e.g., pKa, lipophilicity, target binding) for each TKI were collected and applied in established base PBPK models. Key hallmarks of NSCLC include: immune tumor deprivation, unaltered tumor perfusion and an acidic tumor environment. Model accuracy was demonstrated by calculating the prediction error (PE) between predicted tissue-to-blood ratios (TBR) and measured PET-image-derived TBR. Sensitivity analysis was performed by excluding each key component and comparing the PE with the final mechanistical PBPK model predictions. Results: The developed PBPK models were able to predict tumor-to-lung contrast for all EGFR-TKIs within threefold of observed PET image ratios (PE tumor-to-lung ratio of −90%, +44% and −6.3% for erlotinib, afatinib and osimertinib, respectively). Furthermore, the models depicted agreeable whole-body distribution, showing high tissue distribution for osimertinib and afatinib and low tissue distribution at high blood concentrations for erlotinib (mean PE, of −10.5%, range −158%–+190%, for all tissues). Conclusion: The developed PBPK models adequately predicted the image quality of afatinib and osimertinib and erlotinib. Some deviations in predicted whole-body TBR lead to new hypotheses, such as increased affinity for mutated EGFR and active influx transport (erlotinib into excreting tissues) or active efflux (afatinib from brain), which is currently unaccounted for. In the future, PBPK models may be used to predict the image quality of new tracers.

New PET Tracers: Current Knowledge and Perspectives in Lung Cancer

PET/CT with the tracer 2-[¹⁸F]fluoro-2-deoxy-D-glucose ([¹⁸F]FDG) has improved diagnostic imaging in cancer and is routinely used for diagnosing, staging and treatment planning in lung cancer patients. However, pitfalls of [¹⁸F]FDG-PET/CT limit the use in specific settings. Additionally, lung cancer is still the leading cause of cancer associated death and has high risk of recurrence after curative treatment. These circumstances have led to the continuous search for more sensitive and specific PET tracers to optimize lung cancer diagnosis, staging, treatment planning and evaluation. The objective of this review is to present and discuss current knowledge and perspectives of new PET tracers for use in lung cancer. A literature search was performed on PubMed and clinicaltrials.gov, limited to the past decade, excluding case reports, preclinical studies and studies on established tracers such as [¹⁸F]FDG and DOTATE. The most relevant papers from the search were evaluated. Several tracers have been developed targeting specific tumor characteristics and hallmarks of cancer. A small number of tracers have been studied extensively and evaluated head-to-head with [¹⁸F]FDG-PET/CT, whereas others need further investigation and validation in larger clinical trials. At this moment, none of the tracers can replace [¹⁸F]FDG-PET/CT. However, they might serve as supplementary imaging methods to provide more knowledge about biological tumor characteristics and visualize intra- and inter-tumoral heterogeneity.

Prognostic Significance of PD-L1 Expression and Standardized Uptake Values in the Primary Lesions of Stage IV Adenocarcinoma Lung Cancer

Background

This study evaluated the prognostic ability of ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET)/computed tomography (CT) in patients with stage IV adenocarcinoma lung cancer to detect protein death-ligand 1 (PD-L1) expression levels.

Methods

In total, 86 patients with stage IV adenocarcinoma lung cancer underwent ¹⁸F-FDG PET/CT imaging and PD-L1 expression evaluation before treatment from February 2019 to November 2020 at Bach Mai Hospital, Hanoi, Vietnam. The assessed patient characteristics in this study included sex, age, smoking status, epidermal growth factor receptor (EGFR) mutation, PD-L1 expression level, survival status, tumor, node, and metastasis (TNM) stage, and metastasis locations.

Results

The average age was 62.23 ± 9.51 years, and men and women represented 67.4% and 32.6% of the population, respectively. The EGFR mutation rate was 36%. PD-L1 expression was negative (detected in <1% of the tumor) in 40.7% of cases and positive in 59.3% of cases (detected in 1–49% of the tumor in 32.6%; detected in ≥50% of the tumor in 26.7%). The mean maximum standardized uptake value (SUV_max) was 11.09 ± 3.94. SUV_max was significantly higher in PD-L1–positive tumors than in PD-L1–negative tumors (12.24 ± 4.01 and 9.43 ± 3.22, respectively; p = 0.001). Receiver operating characteristic curve analysis revealed an area under the curve of SUVmax was 0.681 (95% confidence interval 0.570–0.793, p = 0.004). Compared with PD-L1–negative cases, SUV_max was significantly different in all PD-L1–positive cases (p = 0.001), weakly PD-L1–positive cases (1–49%, p = 0.005), and strongly PD-L1–positive cases (≥50%, p = 0.003). PD-L1 expression levels were significantly associated with SUV_max (p = 0.001), tumor size (p = 0.022), and EGFR mutation status (p = 0.045).

Conclusions

SUV_max in the primary lesions was able to predict PD-L1 expression and may play a role in predicting PD-L1 immunotherapy efficacy in patients with stage IV lung adenocarcinoma.

Relationship between Biodistribution and Tracer Kinetics of 11C-Erlotinib, 18F-Afatinib and 11C-Osimertinib and Image Quality Evaluation Using Pharmacokinetic/Pharmacodynamic Analysis in Advanced Stage Non-Small Cell Lung Cancer Patients

Background: Patients with non-small cell lung cancer (NSCLC) driven by activating epidermal growth factor receptor (EGFR) mutations are best treated with therapies targeting EGFR, i.e., tyrosine kinase inhibitors (TKI). Radiolabeled EGFR-TKI and PET have been investigated to study EGFR-TKI kinetics and its potential role as biomarker of response in NSCLC patients with EGFR mutations (EGFRm). In this study we aimed to compare the biodistribution and kinetics of three different EGFR-TKI, i.e., 11C-erlotinib, 18F-afatinib and 11C-osimertinib. Methods: Data of three prospective studies and 1 ongoing study were re-analysed; data from thirteen patients (EGFRm) were included for 11C-erlotinib, seven patients for 18F-afatinib (EGFRm and EGFR wild type) and four patients for 11C-osimertinib (EGFRm). From dynamic and static scans, SUV and tumor-to-blood (TBR) values were derived for tumor, lung, spleen, liver, vertebra and, if possible, brain tissue. AUC values were calculated using dynamic time-activity-curves. Parent fraction, plasma-to-blood ratio and SUV values were derived from arterial blood data. Tumor-to-lung contrast was calculated, as well as (background) noise to assess image quality. Results: 11C-osimertinib showed the highest SUV and TBR (AUC) values in nearly all tissues. Spleen uptake was notably high for 11C-osimertinib and to a lesser extent for 18F-afatinib. For EGFRm, 11C-erlotinib and 18F-afatinib demonstrated the highest tumor-to-lung contrast, compared to an inverse contrast observed for 11C-osimertinib. Tumor-to-lung contrast and spleen uptake of the three TKI ranked accordingly to the expected lysosomal sequestration. Conclusion: Comparison of biodistribution and tracer kinetics showed that 11C-erlotinib and 18F-afatinib demonstrated the highest tumor-to-background contrast in EGFRm positive tumors. Image quality, based on contrast and noise analysis, was superior for 11C-erlotinib and 18F-afatinib (EGFRm) scans compared to 11C-osimertinib and 18F-afatinib (EGFR wild type) scans.

NSCLC Biomarkers to Predict Response to Immunotherapy with Checkpoint Inhibitors (ICI): From the Cells to In Vivo Images

Lung cancer remains the leading cause of cancer-related death, and it is usually diagnosed in advanced stages (stage III or IV). Recently, the availability of targeted strategies and of immunotherapy with checkpoint inhibitors (ICI) has favorably changed patient prognosis. Treatment outcome is closely related to tumor biology and interaction with the tumor immune microenvironment (TME). While the response in molecular targeted therapies relies on the presence of specific genetic alterations in tumor cells, accurate ICI biomarkers of response are lacking, and clinical outcome likely depends on multiple factors that are both host and tumor-related. This paper is an overview of the ongoing research on predictive factors both from in vitro/ex vivo analysis (ranging from conventional pathology to molecular biology) and in vivo analysis, where molecular imaging is showing an exponential growth and use due to technological advancements and to the new bioinformatics approaches applied to image analyses that allow the recovery of specific features in specific tumor subclones.

Combining PD-L1 Expression and Standardized Uptake Values in FDG-PET/CT Can Predict Prognosis in Patients With Resectable Non-Small-Cell Lung Cancer

Background

This study aimed to determine the relationship of programmed death-ligand 1 (PD-L1) expression and standardized uptake values in fluorodeoxyglucose–positron emission tomography/computed tomography (FDG-PET/CT) with prognosis in non–small-cell lung cancer (NSCLC).

Methods

We retrospectively analyzed 328 NSCLC patients who underwent lobectomy/segmentectomy with lymph node dissection. PD-L1 expression was detected by immunohistochemically stained using the murine monoclonal antibody clone 22C3. The preoperative maximum standardized uptake value (SUV_max) of FDG-PET/CT at the primary lesion; pathological factors including histological type, microscopic lymphatic, venous, and pleural invasion; and lymph node metastases in resected specimens was determined. Significant prognostic clinicopathologic factors were analyzed by univariate and multivariate analyses.

Results

PD-L1 expression was higher in men, smokers, squamous cell carcinoma, advanced pathologic stages, positive venous invasion, positive pleural invasion, and high preoperative SUV_max (≥3). Postoperative survival analysis showed that both PD-L1 expression and preoperative SUV_max were significantly negative prognostic factors in univariate analysis for overall survival (OS) (P = 0.0123 and P < 0.0001) and relapse-free survival (RFS) (P = 0.0012 and P < 0.0001). Kaplan–Meier survival curves showed that the OS and RFS were the best in patients with negative PD-L1 expression and SUV_max < 3, intermediate in patients with positive PD-L1 expression and SUV_max < 3 and those with negative PD-L1 expression and SUV_max ≥ 3, and poor in patients with positive PD-L1 expression and SUV_max ≥ 3.

Conclusion

Combining PD-L1 expression and preoperative FDG-PET/CT SUV_max in primary tumor might help in accurate prediction of postoperative prognosis in NSCLC patients.

Effect of microRNA-4268 on Proliferation and Apoptosis of Non-Small Cell Lung Cancer Cells Through Regulating Signal Transducer and Activator of Transcription 3 Level

STAT3 is closely related to non-small cell lung cancer (NSCLC). miR-4268 is predicted to regulate STAT3 level by MiRDB analysis. Therefore, our study investigated whether miR-4268 affects NSCLC cells by regulating STAT3. The control group (NC group), miR-4268 Mimics group, and miR-4268 Mimics +pFBD-STAT3 group were set up followed by analysis of miR-4268 and STAT3 mRNA level by QRT-PCR, relationship between miR-4268 and STAT3 by dual fluorescein reporter assay, STAT3 and Tubulin protein level by Western blot, cell proliferation by MTT assay and apoptosis by Annexin V-FITC/PI staining. Compared with normal tissue, miR-4268 expression in cancer tissue was significantly reduced (P <0.01), while STAT3 level was elevated (P <0.01). STAT3 was a target gene of miR-4268. Compared with NC group, STAT3 level was significantly reduced in miR-4268 Mimics group (P <0.01) and increased in miR-4268 Mimics+pFBD-STAT3 group compared with miR-4268 Mimics group (P <0.05). Compared to NC group, miR-4268 Mimics group had reduced cell proliferation and increased cell apoptosis and opposite changes were observed in miR-4268 Mimics+pFBD-STAT3 group which had increased cell proliferation and decreased apoptosis (P < 0.05). miR-4268 regulates STAT3 mRNA level and inhibits NSCLC cell proliferation and promotes apoptosis. However, over-expression of STAT3 can inhibit the effect of miR-4268.

Identifying advanced stage NSCLC patients who benefit from afatinib therapy using 18F-afatinib PET/CT imaging

OBJECTIVES

Non-small cell lung cancer (NSCLC) tumors harboring common (exon19del, L858R) and uncommon (e.g. G719X, L861Q) activating epidermal growth factor receptor (EGFR) mutations are best treated with EGFR tyrosine kinase inhibitors (TKI) such as the first-generation EGFR TKI erlotinib, second-generation afatinib or third-generation osimertinib. However, identifying these patients through biopsy is not always possible. Therefore, our aim was to evaluate whether ¹⁸F-afatinib PET/CT could identify patients with common and uncommon EGFR mutations. Furthermore, we evaluated the relation between tumor ¹⁸F-afatinib uptake and response to afatinib therapy.

MATERIALS AND METHODS

¹⁸F-afatinib PET/CT was performed in 12 patients: 6 EGFR wild type (WT), 3 EGFR common and 3 EGFR uncommon mutations. Tumor uptake of ¹⁸F-afatinib was quantified using TBR_WB_60-90 (tumor-to-whole blood activity ratio 60-90 min post-injection) for each tumor. Response was quantified per lesion using percentage of change (PC): [(response measurement (RM)-baseline measurement (BM))/BM]×100. Statistical analyses were performed using t-tests, correlation plots and sensitivity/specificity analysis.

RESULTS

Twenty-one tumors were identified. Injected dose was 348 ± 31 MBq. Group differences were significant between WT versus EGFR (common and uncommon) activating mutations (p = 0.03). There was no significant difference between EGFR common versus uncommon mutations (p = 0.94). A TBR_WB_60-90 cut-off value of 6 showed the best relationship with response with a sensitivity of 70 %, a specificity of 100 % and a positive predictive value of 100 %.

CONCLUSION

¹⁸F-afatinib uptake was higher in tumors with EGFR mutations (common and uncommon) compared to WT. Furthermore, a TBR_WB_60-90 cut-off of 6 was found to best predict response to therapy. ¹⁸F-afatinib PET/CT could provide a means to identify EGFR mutation positive patients who benefit from afatinib therapy.

The Role of VEGF Receptors as Molecular Target in Nuclear Medicine for Cancer Diagnosis and Combination Therapy

Simple Summary

The rapid development of diagnostic and therapeutic methods of the cancer treatment causes that these diseases are becoming better known and the fight against them is more and more effective. Substantial contribution in this development has nuclear medicine that enables very early cancer diagnosis and early start of the so-called targeted therapy. This therapeutic concept compared to the currently used chemotherapy, causes much fewer undesirable side effects, due to targeting a specific lesion in the body. This review article discusses the possible applications of radionuclide-labelled tracers (peptides, antibodies or synthetic organic molecules) that can visualise cancer cells through pathological blood vessel system in close tumour microenvironment. Hence, at a very early step of oncological disease, targeted therapy can involve in tumour formation and growth.

Abstract

One approach to anticancer treatment is targeted anti-angiogenic therapy (AAT) based on prevention of blood vessel formation around the developing cancer cells. It is known that vascular endothelial growth factor (VEGF) and vascular endothelial growth factor receptors (VEGFRs) play a pivotal role in angiogenesis process; hence, application of angiogenesis inhibitors can be an effective approach in anticancer combination therapeutic strategies. Currently, several types of molecules have been utilised in targeted VEGF/VEGFR anticancer therapy, including human VEGF ligands themselves and their derivatives, anti-VEGF or anti-VEGFR monoclonal antibodies, VEGF binding peptides and small molecular inhibitors of VEGFR tyrosine kinases. These molecules labelled with diagnostic or therapeutic radionuclides can become, respectively, diagnostic or therapeutic receptor radiopharmaceuticals. In targeted anti-angiogenic therapy, diagnostic radioagents play a unique role, allowing the determination of the emerging tumour, to monitor the course of treatment, to predict the treatment outcomes and, first of all, to refer patients for AAT. This review provides an overview of design, synthesis and study of radiolabelled VEGF/VEGFR targeting and imaging agents to date. Additionally, we will briefly discuss their physicochemical properties and possible application in combination targeted radionuclide tumour therapy.

Genotype Driven Therapy for Non-Small Cell Lung Cancer: Resistance, Pan Inhibitors and Immunotherapy

Eighty-five percent of patients with lung cancer present with Non-small Cell Lung Cancer (NSCLC). Targeted therapy approaches are promising treatments for lung cancer. However, despite the development of targeted therapies using Tyrosine Kinase Inhibitors (TKI) as well as monoclonal antibodies, the five-year relative survival rate for lung cancer patients is still only 18%, and patients inevitably become resistant to therapy. Mutations in Kirsten Ras Sarcoma viral homolog (KRAS) and epidermal growth factor receptor (EGFR) are the two most common genetic events in lung adenocarcinoma; they account for 25% and 20% of cases, respectively. Anaplastic Lymphoma Kinase (ALK) is a transmembrane receptor tyrosine kinase, and ALK rearrangements are responsible for 3-7% of NSCLC, predominantly of the adenocarcinoma subtype, and occur in a mutually exclusive manner with KRAS and EGFR mutations. Among drug-resistant NSCLC patients, nearly half exhibit the T790M mutation in exon 20 of EGFR. This review focuses on some basic aspects of molecules involved in NSCLC, the development of resistance to treatments in NSCLC, and advances in lung cancer therapy in the past ten years. Some recent developments such as PD-1-PD-L1 checkpoint-based immunotherapy for NSCLC are also covered.

Role of theranostics in thoracic oncology

Theranostics is a re-emerging field of medicine that aims to create targeted agents that can be used for diagnostic and/or therapeutic indications. In the past, theranostics has been used to treat neoplasms, such as thyroid cancer and neuroblastomas. More recently, theranostics has seen a resurgence with advent of new therapeutic antibodies and small molecules which can be transformed into Theranostic agents through radioconjugating with a radioactive isotope. Positron emitting radioisotopes can be used for diagnostic purposes while alpha- and beta-emitting radioisotopes can be used for therapy. The technique of radiolabeling an existing therapeutic agent (small molecule or antibody) leverages the existing qualities of that drug, and potentiates therapeutic effect by conjugating it with a cytotoxic-energy bearing radioisotope (e.g., 131-iodine, 177-lutetium). Theranostics have been used for a few decades now, starting with 131-iodine for therapy of autoimmune thyroiditis (Graves’ disease, Hashimoto’s thyroiditis) as well as for thyroid cancer. Additionally, 131-iodine-meta-iodobenzylguanidine (131-I-MIBG) initially had been used for gastroenteropancreatic neuroendocrine (carcinoid) tumors. However, recently clinical trials have start enrolling patients to evaluate efficacy of 131-I-MIBG in patients with small cell carcinoma of the lung. In the era of precision medicine and personalized targeted therapeutics, Theranostics can play a key pivotal in improving diagnostic and therapeutic specificity by increasing potency of these targeted small molecules and antibodies with radioisotopes. In this review, we will review various clinically relevant Theranostics agent and their utility in thoracic disorders, notably within oncology.

Efficacy of a small molecule inhibitor of the transcriptional cofactor PC4 in prevention and treatment of non-small cell lung cancer

The human positive coactivator 4 (PC4) was originally identified as a multi-functional cofactor capable of mediating transcription activation by diverse gene- and tissue-specific activators. Recent studies suggest that PC4 might also function as a novel cancer biomarker and therapeutic target for different types of cancers. siRNA knockdown studies indicated that down-regulation of PC4 expression could inhibit tumorigeneicity of A549 non-small cell lung cancer tumor model in nude mice. Here we show that AG-1031, a small molecule identified by high throughput screening, can inhibit the double-stranded DNA binding activity of PC4, more effectively than its single-stranded DNA binding activity. AG-1031 also specifically inhibited PC4-dependent transcriptional activation in vitro using purified transcription factors. AG-1031 inhibited proliferation of several cultured cell lines derived from non-small cell lung cancers (NSCLC) and growth of tumors that formed from A549 cell xenografts in immuno-compromised mice. Moreover, pre-injection of AG-1031 in these mice not only reduced tumor size, but also prevented tumor formation in 20% of the animals. AG-1031 treated A549 cells and tumors from AG-1031 treated animals showed a significant decrease in the levels of both PC4 and VEGFC, a key mediator of angiogenesis in cancer. On the other hand, all tested mice remained constant weight during animal trials. These results demonstrated that AG-1031 could be a potential therapy for PC4-positive NSCLC.

Intellectual Structure and Evolutionary Trends of Precision Medicine Research: Coword Analysis

BACKGROUND

Precision medicine (PM) is playing a more and more important role in clinical practice. In recent years, the scale of PM research has been growing rapidly. Many reviews have been published to facilitate a better understanding of the status of PM research. However, there is still a lack of research on the intellectual structure in terms of topics.

OBJECTIVE

This study aimed to identify the intellectual structure and evolutionary trends of PM research through the application of various social network analysis and visualization methods.

METHODS

The bibliographies of papers published between 2009 and 2018 were extracted from the Web of Science database. Based on the statistics of keywords in the papers, a coword network was generated and used to calculate network indicators of both the entire network and local networks. Communities were then detected to identify subdirections of PM research. Topological maps of networks, including networks between communities and within each community, were drawn to reveal the correlation structure. An evolutionary graph and a strategic graph were finally produced to reveal research venation and trends in discipline communities.

RESULTS

The results showed that PM research involves extensive themes and, overall, is not balanced. A minority of themes with a high frequency and network indicators, such as Biomarkers, Genomics, Cancer, Therapy, Genetics, Drug, Target Therapy, Pharmacogenomics, Pharmacogenetics, and Molecular, can be considered the core areas of PM research. However, there were five balanced theme directions with distinguished status and tendencies: Cancer, Biomarkers, Genomics, Drug, and Therapy. These were shown to be the main branches that were both focused and well developed. Therapy, though, was shown to be isolated and undeveloped.

CONCLUSIONS

The hotspots, structures, evolutions, and development trends of PM research in the past ten years were revealed using social network analysis and visualization. In general, PM research is unbalanced, but its subdirections are balanced. The clear evolutionary and developmental trend indicates that PM research has matured in recent years. The implications of this study involving PM research will provide reasonable and effective support for researchers, funders, policymakers, and clinicians.

PET Imaging of Receptor Tyrosine Kinases in Cancer

Overexpression and/or mutations of the receptor tyrosine kinase (RTK) subfamilies, such as epidermal growth factor receptors (EGFR) and vascular endothelial growth factor receptors (VEGFR), are closely associated with tumor cell growth, differentiation, proliferation, apoptosis, and cellular invasiveness. Monoclonal antibodies (mAb) and tyrosine kinase inhibitors (TKI) specifically inhibiting these RTKs have shown remarkable success in improving patient survival in many cancer types. However, poor response and even drug resistance inevitably occur. In this setting, the ability to detect and visualize RTKs with noninvasive diagnostic tools will greatly refine clinical treatment strategies for cancer patients, facilitate precise response prediction, and improve drug development. Positron emission tomography (PET) agents using targeted radioactively labeled antibodies have been developed to visualize tumor RTKs and are changing clinical decisions for certain cancer types. In the present review, we primarily focus on PET imaging of RTKs using radiolabeled antibodies with an emphasis on the clinical applications of these immunoPET probes. Mol Cancer Ther; 17(8); 1625-36. ©2018 AACR.

Intrinsic resistance to EGFR-Tyrosine Kinase Inhibitors in EGFR-Mutant Non-Small Cell Lung Cancer: Differences and Similarities with Acquired Resistance

Activating mutations in the epidermal growth factor receptor gene occur as early cancer-driving clonal events in a subset of patients with non-small cell lung cancer (NSCLC) and result in increased sensitivity to EGFR-tyrosine-kinase-inhibitors (EGFR-TKIs). Despite very frequent and often prolonged clinical response to EGFR-TKIs, virtually all advanced EGFR-mutated (EGFRM+) NSCLCs inevitably acquire resistance mechanisms and progress at some point during treatment. Additionally, 20-30% of patients do not respond or respond for a very short time (<3 months) because of intrinsic resistance. While several mechanisms of acquired EGFR-TKI-resistance have been determined by analyzing tumor specimens obtained at disease progression, the factors causing intrinsic TKI-resistance are less understood. However, recent comprehensive molecular-pathological profiling of advanced EGFRM+ NSCLC at baseline has illustrated the co-existence of multiple genetic, phenotypic, and functional mechanisms that may contribute to tumor progression and cause intrinsic TKI-resistance. Several of these mechanisms have been further corroborated by preclinical experiments. Intrinsic resistance can be caused by mechanisms inherent in EGFR or by EGFR-independent processes, including genetic, phenotypic or functional tumor changes. This comprehensive review describes the identified mechanisms connected with intrinsic EGFR-TKI-resistance and differences and similarities with acquired resistance and among clinically implemented EGFR-TKIs of different generations. Additionally, the review highlights the need for extensive pre-treatment molecular profiling of advanced NSCLC for identifying inherently TKI-resistant cases and designing potential combinatorial targeted strategies to treat them.

Correlative analysis of miR-34b and p53 with pathological characteristics of NSCLC

The expression of miR-34b and p53 in non-small cell lung cancer (NSCLC) was investigated to explore its relationship with clinical pathology of NSCLC. Reverse transcription-quantitative PCR (RT-qPCR) method was used to quantitatively analyze miR-34b and p53 in cancer tissue and adjacent paraneoplastic (PTLC) tissue in 54 cases of NSCLC. The relationship between gene expression and clinical pathological data was analyzed. The expression of miR-34b in tumor tissues of NSCLC patients was significantly downregulated in comparison with PTLC. The expression level of miR-34b was negatively correlated with lymph node metastasis. It was positively correlated with the degree of differentiation and negatively correlated with the pathological stage (P<0.05). There was no significant association in the expression of miR-34b with age, sex, histological type, and gross classification (all P>0.05). The expression of p53 in the tumor tissue of NSCLC patients was significantly reduced in comparison with PTLC, and its expression was negatively correlated with the pathological stage, lymph node metastasis, and was positively correlated with the degree of differentiation. The expression of p53 in adenocarcinoma was generally higher than that of squamous cell carcinoma and large cell carcinoma. The expression of p53 in central type cancer was significantly higher than that in peripheral type (P<0.05). The expression of miR-34b and p53 was positively correlated in NSCLC tissues (r=0.797, P<0.001). The high expression of miR-34b and p53 is closely related to the clinical stage and pathological grade of NSCLC. miR-34b and p53 may serve as important tumor markers for NSCLC.

Maximizing quality of life remains an ultimate goal in the era of precision medicine: exemplified by lung cancer

An ultimate goal of precision medicine in lung cancer treatment is to restore patient health with maximized quality of life (QOL). Results from Mayo Clinic studies show that a significant improvement in fatigue, dyspnea, and pain scales could lead to better overall QOL. Although treatments and guidelines for clinical implementation to alleviate these key symptoms are available, few cancer patients receive adequate therapy, mostly because of limitations in current care delivery systems and unclear clinicians’ roles. For optimal care of lung cancer survivors in different subpopulations, three barriers must be overcome: physicians’ lack of knowledge, unwarranted practice variation, and uncertainty regarding care provider roles. Appropriate culturally adapted, tested and validated tools for QOL measures must be developed, rather than directly translating existing tools between different languages and across cultures or diverse subpopulations. Finally, lack of sensitive, adequate, and relevant tools in measuring health-related QOL (HRQOL) has long been an issue for effective data collection, demanding a global consensus on a set of core components that reflect the needs of all critical parties for the best cure and care, supporting patients to achieve optimal HRQOL.

The developing role of FDG PET imaging for prognostication and radiotherapy target volume delineation in non-small cell lung cancer

Advancements in functional imaging technology have allowed new possibilities in contouring of target volumes, monitoring therapy, and predicting treatment outcome in non-small cell lung cancer (NSCLC). Consequently, the role of ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG PET) has expanded in the last decades from a stand-alone diagnostic tool to a versatile instrument integrated with computed tomography (CT), with a prominent role in lung cancer radiotherapy. This review outlines the most recent literature on developments in FDG PET imaging for prognostication and radiotherapy target volume delineation (TVD) in NSCLC. We also describe the challenges facing the clinical implementation of these developments and present new ideas for future research.

Value of 18F-FDG PET/CT for predicting EGFR mutations and positive ALK expression in patients with non-small cell lung cancer: a retrospective analysis of 849 Chinese patients

PURPOSE

Epidermal growth factor receptor (EGFR) mutations and the anaplastic lymphoma kinase (ALK) rearrangement are the two most common druggable targets in non-small cell lung cancer (NSCLC). However, genetic testing is sometimes unavailable. Previous studies regarding the predictive role of 18F-FDG PET/CT for EGFR mutations in NSCLC patients are conflicting. We investigated whether or not 18F-FDG PET could be a valuable noninvasive method to predict EGFR mutations and ALK positivity in NSCLC using the largest patient cohort to date.

METHODS

We retrospectively reviewed and included 849 NSCLC patients who were tested for EGFR mutations or ALK status and subjected to 18F-FDG PET/CT prior to treatment. The differences in several clinical characteristics and three parameters based on 18F-FDG PET/CT, including the maximal standard uptake value (SUVmax) of the primary tumor (pSUVmax), lymph node (nSUVmax) and distant metastasis (mSUVmax), between the different subgroups were analyzed. Multivariate logistic regression analysis was performed to identify predictors of EGFR mutations and ALK positivity.

RESULTS

EGFR mutations were identified in 371 patients (45.9%). EGFR mutations were found more frequently in females, non-smokers, adenocarcinomas and stage I disease. Low pSUVmax, nSUVmax and mSUVmax were significantly associated with EGFR mutations. Multivariate analysis demonstrated that pSUVmax < 7.0, female sex, non-smoker status and adenocarcinoma were predictors of EGFR mutations. The receiver operating characteristic (ROC) curve yielded area under the curve (AUC) values of 0.557 and 0.697 for low pSUVmax alone and the combination of the four factors, respectively. ALK-positive patients tended to have a high nSUVmax. Younger age and distant metastasis were the only two independent predictors of ALK positivity.

CONCLUSION

We demonstrated that low pSUVmax is associated with mutant EGFR status and could be integrated with other clinical factors to enhance the discriminability on the EGFR mutation status in some NSCLC patients whose EGFR testing is unavailable.

Immunotherapy in metastatic urothelial carcinoma: focus on immune checkpoint inhibition

Immunotherapy has been used in localized urothelial carcinoma for decades, especially in the treatment of superficial disease, in which instillation of BCG is a commonly used treatment option. Clinical investigations based on new insights into the immunogenic potential of metastatic urothelial carcinoma have led to the accelerated FDA approval of the immune checkpoint inhibitors atezolizumab, nivolumab, durvalumab, avelumab, and pembrolizumab. Preliminary findings suggest additional benefits of combinations of immunotherapeutic agents as a future treatment approach in metastatic urothelial carcinoma. Treatment experience with immunotherapy suggests that these drugs are associated with a unique spectrum of immune-related adverse events and specific immune-related patterns of response, including cases of pseudoprogression, which could impede the optimal use of immune checkpoint inhibitors in the clinic. Appropriate management of immune-related adverse events and a greater awareness of immune-mediated response patterns will help to inform treatment decisions and improve patient outcomes; predictive biomarkers of response might facilitate selection of patients who are most likely to respond to and benefit from these exciting new treatments.

Genomic Characterization of Lung Cancer and Its Impact on the Use and Timing of PET in Therapeutic Response Assessment

Significant advances in understanding the genomic landscape of non-small cell lung cancer (NSCLC) together with the coupling discovery of key oncogenic drivers and the development of effective targeted and immunotherapeutic agents have revolutionized the management of this malignancy. Although these therapies have resulted in improved outcomes for a subgroup of patients, their benefit may not necessarily be reflected by conventional response assessment criteria, because these therapeutic agents differ in their mechanism of action and response time compared with cytotoxic chemotherapy. Here the authors review available therapies in NSCLC and the utility of PET in therapeutic response assessment.

Development of Antibody-Drug Conjugates Using DDS and Molecular Imaging

Antibody-drug conjugate (ADC), as a next generation of antibody therapeutics, is a combination of an antibody and a drug connected via a specialized linker. ADC has four action steps: systemic circulation, the enhanced permeability and retention (EPR) effect, penetration within the tumor tissue, and action on cells, such as through drug delivery system (DDS) drugs. An antibody with a size of about 10 nm has the same capacity for passive targeting as some DDS carriers, depending on the EPR effect. In addition, some antibodies are capable of active targeting. A linker is stable in the bloodstream but should release drugs efficiently in the tumor cells or their microenvironment. Thus, the linker technology is actually a typical controlled release technology in DDS. Here, we focused on molecular imaging. Fluorescent and positron emission tomography (PET) imaging is useful for the visualization and evaluation of antibody delivery in terms of passive and active targeting in the systemic circulation and in tumors. To evaluate the controlled release of the ADC in the targeted area, a mass spectrometry imaging (MSI) with a mass microscope, to visualize the drug released from ADC, was used. As a result, we succeeded in confirming the significant anti-tumor activity of anti-fibrin, or anti-tissue factor-ADC, in preclinical settings by using DDS and molecular imaging.

Molecularly targeted therapies in cancer: a guide for the nuclear medicine physician

Molecular imaging continues to influence every aspect of cancer care including detection, diagnosis, staging and therapy response assessment. Recent advances in the understanding of cancer biology have prompted the introduction of new targeted therapy approaches. Precision medicine in oncology has led to rapid advances and novel approaches optimizing the use of imaging modalities in cancer care, research and development. This article focuses on the concept of targeted therapy in cancer and the challenges that exist for molecular imaging in cancer care.