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Since the introduction of PET/CT hybrid imaging about two decades ago the landscape of oncological imaging has fundamentally changed, opening a new era of molecular imaging with emphasis on functional characterization of biological processes such as metabolism, cellular proliferation, hypoxia, apoptosis, angiogenesis and immune response. The most commonly assessed functional hallmark of cancer is the increased metabolism in tumor cells due to well-known Warburg effect, because of which FDG has been the most employed radiotracer, the so-called pan-cancer agent, in oncological imaging. However, several limitations such as low specificity and low sensitivity for several histopathological forms of lung cancer as well as high background uptake in the normal tissue of FDG imaging lead to numerous serious pitfalls. This restricts its utilization and diagnostic value in lung cancer imaging, even though this is currently considered to be the method of choice in pulmonary cancer imaging. Accurate initial tumor staging and therapy response monitoring with respect to the TNM criteria plays a crucial role in therapy planning and management in patients with lung cancer. To this end, many efforts have been made for decades to develop novel PET radiopharmaceuticals with innovative approaches that go beyond the assessment of increased glycolytic activity alone. Radiopharmaceuticals targeting DNA synthesis, amino acid metabolism, angiogenesis, or hypoxia have been extensively studied, leading to the emergence of indications for specific clinical questions or as a complementary imaging tool alongside existing conventional or FDG imaging. Nevertheless, despite some initial encouraging results, these tracers couldn't gain a widespread use and acceptance in clinical routine. However, given its mechanism of action and some initial pilot studies regarding lung cancer imaging, FAPI has emerged as a very promising alternative tool that could provide superior or comparable diagnostic performance to FDG imaging in lung cancer entities. Thus, in this review article, we summarized the current PET radiopharmaceuticals, different imaging approaches and discussed the potential benefits and clinical applications of these agents in lung cancer imaging.

Crucial transitions in cancer-including tumor initiation, local expansion, metastasis, and therapeutic resistance-involve complex interactions between cells within the dynamic tumor ecosystem. Transformative single-cell genomics technologies and spatial multiplex in situ methods now provide an opportunity to interrogate this complexity at unprecedented resolution. The Human Tumor Atlas Network (HTAN), part of the National Cancer Institute (NCI) Cancer Moonshot Initiative, will establish a clinical, experimental, computational, and organizational framework to generate informative and accessible three-dimensional atlases of cancer transitions for a diverse set of tumor types. This effort complements both ongoing efforts to map healthy organs and previous large-scale cancer genomics approaches focused on bulk sequencing at a single point in time. Generating single-cell, multiparametric, longitudinal atlases and integrating them with clinical outcomes should help identify novel predictive biomarkers and features as well as therapeutically relevant cell types, cell states, and cellular interactions across transitions. The resulting tumor atlases should have a profound impact on our understanding of cancer biology and have the potential to improve cancer detection, prevention, and therapeutic discovery for better precision-medicine treatments of cancer patients and those at risk for cancer.

Tachykinin-1 (TAC1) is the precursor protein for neuroendocrine peptides, including substance P, and is centrally involved in gastric secretion, motility, mucosal immunity, and cell proliferation. Here we report aberrant silencing of TAC1 in gastric cancer (GC) by promoter hypermethylation. TAC1 methylation and mRNA expression in 47 primary GCs and 41 noncancerous gastric mucosae (NLs) were analyzed by utilizing real-time quantitative PCR-based assays. TAC1 methylation was more prevalent in GCs than in NLs: 21 (45%) of 47 GCs versus 6 (15%) of 41 NLs (p

Background & Aims: Gene silencing via promoter hypermethylation is a central event in the pathogenesis of cancers. To identify novel methylation targets in colon cancer, we conducted a genome-wide, microarray-based, in silico, and epigenetic search. Methods: Complementary DNA microarray experiments were first performed to identify genes down-regulated in primary colon cancers and up-regulated in colon cancer cell lines after global DNA demethylation by 5-aza-2′-deoxycitidine. Candidate methylation targets were then identified by combining these microarray data with in silico genetic and functional searches. Candidate genes recognized by these searches were further investigated for promoter hypermethylation in colon cancer using methylation-specific polymerase chain reaction. Results: We identified 51 novel and 3 known candidate methylation targets. Subsequent epigenetic analysis revealed that primary colon cancers demonstrated frequent methylation of somatostatin (SST, 30 of 34 cases, 88%) and the substance P precursor gene tachykinin-1 (TAC1; 16 of 34 cases, 47%). TAC1 methylation intensity was significantly higher in Dukes A/B than in Dukes C/D cancers (P = .01). SST methylation intensity was significantly higher in low-level microsatellite instability (MSI-L) than in non-MSI-L cancers (P = .02). Methylation was associated with messenger RNA down-regulation for both SST and TAC1. Furthermore, we isolated 5 additional novel promoter methylation targets: NELL1, AKAP12, caveolin-1, endoglin, and MAL. Conclusions: These data strongly suggest that SST and TAC1 are involved in colon carcinogenesis. Further studies are now indicated to elucidate mechanisms underlying their involvement in colon cancer and their values as clinical biomarkers. NELL1, AKAP12, caveolin-1, endoglin, and MAL are also promising tumor suppressor gene candidates deserving of further study.

The activin type II receptorgene (ACTRII) is mutated in 58.1% of microsatellite-unstable (MSI-H) colorectal cancers and is a close relative of the TGFbeta-1 type II receptor, which is known to be involved in both MSI-H and non-MSI-H colorectal carcinogenesis. We therefore sought to determine whether ACTRII was involved in non-MSI-H colorectal cancers. We evaluated ACTRII inactivation by allelic deletion, loss of mRNA expression, or somatic mutation in 51 non-MSI-H colon cancers. Loss of heterozygosity (LOH) at the ACTRII locus (2q23.1) was found in 9 (17.6%) of 51 primary tumors. Loss of ACTRII mRNA expression was seen in one (14.3%) of the seven LOH-positive primary tumors from which total RNA was available. We also performed DNA sequencing analysis of tumors showing LOH. One LOH-positive primary tumor exhibited a novel germline missense sequence alteration (amino acid substitution, 117 Ile to Phe) that was not found in 23 additional normal individuals, implying that this alteration is not a frequent polymorphism. We conclude that ACTRII is probably involved in both non-MSI-H and MSI-H colorectal carcinogenesis, but more frequently in the latter subgroup.

Background & Objective: In the United States, colorectal cancer (CRC) is the third most prevalent and deadly malignancy. Development of novel CRC-specific abnormal DNA biomarkers may advance non-invasive, cost-efficient population-based CRC screening and ultimately reduces CRC death. DNA hypermethylation is a common epigenetic abnormality in CRCs and represents a promising class of cancer biomarkers. The objective of the current study was to develop optimal DNA hypermethylation-based biomarkers for use in fecesor serum-based average-risk CRC screening. Design: We first applied DNAmethylationmicroarray analysis in order to identify novel loci demonstrating neoplasia-specific methylation in the colon. This array analysis allowed us to investigate 55% of CpG islands within the genome and was applied to 17 primary CRCs relative to 8 non-neoplastic colonic tissues (NCs) from neoplasia-free subjects. The detected CRC-associated hypermethylation events were then individually measured in 113 colonic tissues comprising 51 CRCs, 9 adenomas, 19 NCs from CRC patients (CRC-NCs), and 34 NCs from neoplasia-free subjects (control NCs) using highly sensitive and quantitative real-time quantitative methylation-specific PCR (qMSP) assays. Receiver-operator characteristics (ROC) curve analysis was applied to the qMSP data in order to assess each individual event as well as combination of events for their ability to discriminate neoplastic from non-neoplastic cases. Results: Microarray-based global methylation profiles discriminated CRCs from NCs. A bioinformatic filtering of the microarray data identified 169 candidate CRC-associated hypermethylation events, including one previously validated hypermethylation marker for fecal DNA-based CRC detection, SFRP2. Fourteen of these 169 loci were evaluated using qMSP assays. Ten of these 14 methylation events significantly distinguished CRCs from control NCs (p

Background. Cholangiocarcinoma (CCA) is an aggressive epithelial cancer of the biliary tree with survival measured in months. The only potentially curative treatment for CCA is surgical resection. Unfortunately, the vast majority of patients are diagnosed at late stages, when surgery is not an option. MicroRNAs (miRs) are short single stranded RNA sequences, recently shown to have major regulatory functions in cancer. TIMP3 is one of 4 members of the metalloproteinases family and its role was associated with cancer invasion and metastasis. We aimed at elucidating the regulatory mechanisms of TIMP3 in CCA. Methods. Fifteen histologically confirmed CCAs and 9 normal liver specimens were collected at surgery at Johns Hopkins Hospital after informed consent was obtained from all patients. The NLs were obtained at the time of surgery for CCA from normal liver. Quantitative RT-PCR (qRTPCR) for messenger RNA (mRNA) and miRs and quantitative Methylation Specific PCR (qMSP) were performed as previously described. Results. We measured the qRT-PCR level of TIMP3 mRNA and found it to be underexpressed in CCA vs. NL specimens, suggesting a tumor-suppressive role for TIMP3 in the biliary tree. In contrast, our previous work revealed that miR-21 is overexpressed in CCA vs. NL, suggesting a possible negative regulation of TIMP3 by miR-21. In silico searches suggested that TIMP3 is indeed a putative target of miR-21. The CCA cell lines CAK1, TFK1 and HuCCT1 were transfected with a miR-21 inhibitor and TIMP3 protein levels were measured. TIMP3 was significantly elevated in all 3 cell lines transfected with the inhibitor, strongly suggesting that miR-21 downregulates TIMP3 protein levels. Interestingly, miR-21 does not directly bind to TIMP3 mRNA, as evinced by luciferase assays, suggesting the presence of an intermediary molecule or a different mechanism of miR-21 regulation of TIMP3. To investigate a potential co-regulation of TIMP3 in CCA by hypermethylation, we measured the promoter methylation in all 24 specimens. TIMP3 promoter was found to be hypermethylated in only 1/15 CCA (6.6%), 0/3 CCA cell lines and 0/9 NL specimens. Conclusions: TIMP3 mRNA is elevated in NL and decreased in CCA specimens implicating TIMP3 as a tumor suppressor gene in the biliary tree. Our data also suggests that TIMP3 promoter hypermethylation does not appear to play a major role in its downregulation in human CCA specimens. In contrast, miR-21 is a major regulator of TIMP3 in CCA. Furthermore, miR-21 may exert at least part of its oncogenic, pro-invasive effects in CCA by inhibiting TIMP3.

Background: Esophageal cancer (EC) ranks as the eighth most common malignancy and the sixth most frequent cause of cancer death worldwide. EC has an aggressive behavior and tends to recur after surgery and to spread systematically, despite recent surgical and radiotherapeutic advances. Survival of esophageal cancer patients remains poor, approximately 10% for squamous cell carcinoma (ESCC) and 20% for adenocarcinoma (EAD). Therefore, the development of novel therapeutic strategies would be highly beneficial. In gene therapy for any type of malignancy, tumor-specific gene delivery is of utmost importance. The aim of the current study was to identify genes expressed specifically in esophageal cancer cells as candidate promoters of esophageal cancer-specific expressing vector.

Background: Microsatellite instability (MSI) status is currently defined as either microsatellitestable (MSS), low-frequency MSI (MSI-L), or high-frequency MSI (MS1-H). Hypermethylation of CpG islands in the promoter regions of several genes has been associated with MSI status in colorectal cancers. In order to identify novel methylation sites unique to MSI-H or MS1L tumors in an unbused fashion, we conducted an expression profiling-based methylation target search. Methods: 41 primary colorectal cancers (12 MSI-H, 15 MSI-S and 14 MSI-L) were studied with high-density eDNA microarrays, and the bioinformatics methods principal components analysis (PC.A) and significance analysis of microarrays (SAM) were used to identify differentially expressed genes, which were in turn scanned for CpG islands in their putative promoter regions. Results: SAM and PCA identified 166 genes showing significantly different expression levels in MSI-H vs. non-H or in MSI-L vs. MSS colon tumors. 95 of these genes were decreased in mRNA expression in either MSI-H or MSI-L tumors. Genomic chtahase screening revealed that of these 95 genes, 48 had CpG islands within their putative promoter regions. These 48 genes were scanned for expression in normal tissue and for likely cancer-related putative protein functions. This combined approach identified 19 genes vath both CpG islands and significantly differential expression levels between MSI categories. 10 genes were excluded because of pro-carcinogenic (oncogenic) functions. Among the remaining 9 genes, 2 were underexpressed in MSI-L vs. MSS tumors: RBM8A (a binding partner of potential tumor suppressor gene OVCA1) and OAS3 (an IFN-induced protein required to degrade RNA). 7 were underexpressed in MSI-H vs. non-H tumors: RAB32 (ras family gene), PTPRO (a receptor-protein tyrosine phnsphatase), SDBCAG84 (breast cancer anugen 84), HDACll (histone deacetylase), ITPR2 (inositol triphosphate receptor), N33 (putative prostate cancer tumor suppressor), and TSC22 (TGFI~ stimulated transcription regulating factor). Conclusions: The anti-carcinogenic functions of these genes suggest that they are potential targets of tumor-specific methylation. In support of this hypothesis, one gene (N33) is a known tumor suppressor reactivated by promoter hypermethylation in multiple cancers. These results suggest that our approach will identify novel genes involved in the MSI status of colorectal carcinoma.

Microurray And Bioinformatics Analyses Discriminate Among Biologic Subtypes Of Esophageal Neeplasia. Florin M. Selaru, Yan Xu, Univ of Maryland Sch of Medicine, Baltimore, MD; Jing Yin, Valentina Shustova, Tong Zou, Charles Twigg, John M. Abraham, Yudko Mod, Fumiaki Sato, Ion Cotarla, Univ of Maryland, Baltimore, MD; Bruce D. Greenwald, Stephen J. Meitzer, Univ of Maryland Sch of Medicine, Baltimore, MD

A release of serotonin (5-HT), but not that of histamine, from rat peritoneal mast cells, mouse mastocytoma P-815 cells, and rabbit platelets induced by N -(2-ethylhexyl)-3-hydroxybutyramide (butoctamide) in vitro was synergistically augmented by epinephrine or norepinephrine. In the presence of 2.3 mM butoctamide and 270 μM epinephrine, the 5-HT release was optimal at pH 7.4 and 37°, and was suppressed by various enzymic and metabolic inhibitors. A viability test and microscopy indicated that, on exposure to butoctamide and epinephrine, normal mast cells were degranulated, but most of the cells still retained viability. In contrast, neoplastic mast cells showed more severe morphological alterations, and became non-viable.