Plasma mRNA as liquid biopsy predicts chemo-sensitivity in advanced gastric cancer patients

Hidden messages in fluids: A review of clinical and fundamental perspectives on post-lymph node dissection drains

In recent years, there has been a growing interest in liquid biopsy due to its non-invasive diagnostic value. Postoperative drainage fluid (PDF) is the fluid exudate from the wound site following lymph node dissection. PDF is regarded as a medical waste with no specific clinical significance. Nevertheless, the liquid biopsy of PDF may enable the reuse of this fluid. PDF contains a variety of body fluids, including blood and lymph. PDF contains a variety of biological components, including cytokines, extracellular vesicles (EVs), proteins, nucleic acids, cells and bacteria. These components are indicative of the postoperative inflammatory response, the immune response and the therapeutic response. In this review, we examine the current state of research in the field of liquid biopsy in PDF, elucidating how the analysis of its components can assess the prognosis of patients after lymph node dissection, monitor real-time changes in patient status, and identify new biomarkers and potential therapeutic targets.

Helicobacter pylori infection induces POU5F1 upregulation and SPP1 activation to promote chemoresistance and T cell inactivation in gastric cancer cells

Infection with Helicobacter pylori (H. pylori or Hp) is associated with an increased susceptibility to gastric diseases, notably gastric cancer (GC). This study investigates the impact of Hp infection on chemoresistance and immune activity in GC cells. Hp infection in AGS and MKN-74 cells promoted proliferation, migration and invasion, apoptosis resistance, and tumorigenic activity of cells under cisplatin (DDP) plus gemcitabine (GEM) treatment. Additionally, it dampened activity of the co-cultured CD8+ T cells. Hp infection increased POU class 5 homeobox 1 (POU5F1) level, which further activated secreted phosphoprotein 1 (SPP1) transcription to increase its expression. Silencing of either SPP1 or POU5F1 enhanced the GEM sensitivity in GC cells, and it increased the populations of CD8+ T cells and the secretion of immune-active cytokines both in vitro and in xenograft tumors in immunocompetent mice. However, the effects of POU5F1 silencing were counteracted by SPP1 overexpression. Furthermore, the POU5F1/SPP1 axis activated the PI3K/AKT signaling pathway. This study demonstrates that Hp infection induces POU5F1 upregulation and SPP1 activation, leading to increased DDP/GEM resistance and T cell inactivation in GC cells.

Delayed processing of blood samples impairs the accuracy of mRNA-based biomarkers

The transcriptome of peripheral white blood cells (PWBCs) are indicators of an organism's physiological state, thus making them a prime biological sample for mRNA-based biomarker discovery. Here, we designed an experiment to evaluate the impact of delayed processing of whole blood samples on gene transcript abundance in PWBCs. We hypothesized that storing blood samples for 24 h at 4 °C would cause RNA degradation resulting in altered transcriptome profiles. There were no statistical differences in RNA quality parameters among samples processed after one, three, six, or eight hours post collection. Additionally, no significant differences were noted in RNA quality parameters or gene transcript abundance between samples collected from the jugular and coccygeal veins. However, samples processed after 24 h of storage had a lower RNA integrity number value (P = 0.03) in comparison to those processed after one hour of storage. Using RNA-sequencing, we identified four and 515 genes with differential transcript abundance in samples processed after storage for eight and 24 h, respectively, relative to samples processed after one hour. Sequencing coverage of transcripts was similar between samples from the 24-h and one-hour groups, thus showing no indication of RNA degradation. This alteration in transcriptome profiles can impair the accuracy of mRNA-based biomarkers, therefore, blood samples collected for mRNA-based biomarker discovery should be refrigerated immediately and processed within six hours post-sampling.

Photonic technologies for liquid biopsies: recent advances and open research challenges

The recent development of sophisticated techniques capable of detecting extremely low concentrations of circulating tumor biomarkers in accessible body fluids, such as blood or urine, could contribute to a paradigm shift in cancer diagnosis and treatment. By applying such techniques, clinicians can carry out liquid biopsies, providing information on tumor presence, evolution, and response to therapy. The implementation of biosensing platforms for liquid biopsies is particularly complex because this application domain demands high selectivity/specificity and challenging limit-of-detection (LoD) values. The interest in photonics as an enabling technology for liquid biopsies is growing owing to the well-known advantages of photonic biosensors over competing technologies in terms of compactness, immunity to external disturbance, and ultra-high spatial resolution. Some encouraging experimental results in the field of photonic devices and systems for liquid biopsy have already been achieved by using fluorescent labels and label-free techniques and by exploiting super-resolution microscopy, surface plasmon resonance, surface-enhanced Raman scattering, and whispering gallery mode resonators. This paper critically reviews the current state-of-the-art, starting from the requirements imposed by the detection of the most common circulating biomarkers. Open research challenges are considered together with competing technologies, and the most promising paths of improvement are discussed for future applications.

Circulating RNA in blood plasma as diagnostic tool for clinical oncology

One of the key challenges facing today’s oncology is the discovery of early predictors of malignant neoplasms in patients’ biological samples. Liquid biopsy is a noninvasive diagnostic technique based on the detection and isolation of tumor cells, tumor-derived nucleic acid and exosomes circulating in the blood plasma of cancer patients. There is a plethora of research studies of circulating tumor DNA in patients with MN. The active proliferation of tumor cells occurs in the backdrop of altered gene expression. The presence of tissue-specific transcripts in the circulating RNA fraction suggests that levels of circulating RNA reflect the development of the primary tumor. We think that cell-free RNA circulating in the blood plasma is a promising molecular biomarker for early cancer detection.

Gastric Cancer with Radiographically Occult Metastatic Disease: Biology, Challenges, and Diagnostic Approaches

Gastric adenocarcinoma is an aggressive cancer that demonstrates heterogeneous biology depending on patient ethnicity, tumor location, tumor type, and genetic profile. It remains the third leading cause of cancer deaths worldwide and was estimated to result in 782,000 deaths in 2018. Challenges exist in accurately assessing the disease burden, as available radiological staging often underestimates metastatic disease. This diagnostic handicap, along with the poor understanding of the heterogeneous biology of gastric cancer, has hindered the development of effective therapeutic solutions and thus halted improvement in patient outcomes over the last few decades. The management of occult peritoneal disease is complicated, as most patients are understaged by standard imaging studies and therefore thought to have local diseases. In this article, we systematically review recent literature on the limitations that are associated with standard radiographic staging, discuss recent molecular biology advances to better identify and diagnose occult peritoneal disease, and propose possible management strategies to approach this complicated clinical problem.

The Translational Status of Cancer Liquid Biopsies

Abstract

Precision oncology aims to tailor clinical decisions specifically to patients with the objective of improving treatment outcomes. This can be achieved by leveraging omics information for accurate molecular characterization of tumors. Tumor tissue biopsies are currently the main source of information for molecular profiling. However, biopsies are invasive and limited in resolving spatiotemporal heterogeneity in tumor tissues. Alternative non-invasive liquid biopsies can exploit patient’s body fluids to access multiple layers of tumor-specific biological information (genomes, epigenomes, transcriptomes, proteomes, metabolomes, circulating tumor cells, and exosomes). Analysis and integration of these large and diverse datasets using statistical and machine learning approaches can yield important insights into tumor biology and lead to discovery of new diagnostic, predictive, and prognostic biomarkers. Translation of these new diagnostic tools into standard clinical practice could transform oncology, as demonstrated by a number of liquid biopsy assays already entering clinical use. In this review, we highlight successes and challenges facing the rapidly evolving field of cancer biomarker research.

Lay Summary

Precision oncology aims to tailor clinical decisions specifically to patients with the objective of improving treatment outcomes. The discovery of biomarkers for precision oncology has been accelerated by high-throughput experimental and computational methods, which can inform fine-grained characterization of tumors for clinical decision-making. Moreover, advances in the liquid biopsy field allow non-invasive sampling of patient’s body fluids with the aim of analyzing circulating biomarkers, obviating the need for invasive tumor tissue biopsies. In this review, we highlight successes and challenges facing the rapidly evolving field of liquid biopsy cancer biomarker research.

The Prospect and Challenges to the Flow of Liquid Biopsy in Africa

Liquid biopsy technologies have the potential to transform cancer patient management as it offers non-invasive diagnosis and real-time monitoring of disease progression and treatment responses. The use of liquid biopsy for non-invasive cancer diagnosis can have pivotal importance for the African continent where access to medical infrastructures is limited, as it eliminates the need for surgical biopsies. To apply liquid biopsy technologies in the African setting, the influence of environmental and population genetic factors must be known. In this review, we discuss the use of circulating tumor cells, cell-free nucleic acids, extracellular vesicles, protein, and other biomolecules in liquid biopsy technology for cancer management with special focus on African studies. We discussed the prospect, barriers, and other aspects that pose challenges to the use of liquid biopsy in the African continent.

Discovery of plasma messenger RNA as novel biomarker for gastric cancer identified through bioinformatics analysis and clinical validation

Background

Gastric cancer (GC) is the third leading cause of cancer-related death worldwide, partially due to the lack of effective screening strategies. Thus, there is a stringent need for non-invasive biomarkers to improve patient diagnostic efficiency in GC.

Methods

This study initially filtered messenger RNAs (mRNAs) as prospective biomarkers through bioinformatics analysis. Clinical validation was conducted using circulating mRNA in plasma from patients with GC. Relationships between expression levels of target genes and clinicopathological characteristics were calculated. Then, associations of these selected biomarkers with overall survival (OS) were analyzed using the Kaplan-Meier plotter online tool.

Results

Based on a comprehensive analysis of transcriptional expression profiles across 5 microarrays, top 3 over- and underexpressed mRNAs in GC were generated. Compared with normal controls, expression levels of collagen type VI alpha 3 chain (COL6A3), serpin family H member 1 (SERPINH1) and pleckstrin homology and RhoGEF domain containing G1 (PLEKHG1) were significantly upregulated in GC plasmas. Receiver-operating characteristic (ROC) curves on the diagnostic efficacy of plasma COL6A3, SERPINH1 and PLEKHG1 mRNAs in GC showed that the area under the ROC (AUC) was 0.720, 0.698 and 0.833, respectively. Combined, these three biomarkers showed an elevated AUC of 0.907. Interestingly, the higher COL6A3 level was significantly correlated with lymph node metastasis and poor prognosis in GC patients. High level of SERPINH1 mRNA expression was correlated with advanced age, poor differentiation, lower OS, and PLEKHG1 was also associated with poor OS in GC patients.

Conclusion

Our results suggested that circulating COL6A3, SERPINH1 and PLEKHG1 mRNAs could be putative noninvasive biomarkers for GC diagnosis and prognosis.

The circulating transcriptome as a source of cancer liquid biopsy biomarkers

Non-invasive biomarkers or liquid biopsies have the potential to revolutionise cancer patient management as repeated sampling allows real-time monitoring of disease progression and response to treatment. This allows for earlier intervention and dynamic treatment management; both cornerstones of personalised medicine. The circulating transcriptome represents a rich source of potential cancer biomarkers that includes many classes of RNA, both coding and non-coding, that are only now beginning to be explored. In particular the increasing power and availability of RNAseq techniques have pushed studies beyond circulating miRNAs, to other classes of RNA including mRNA, snRNA, snoRNA, piRNA, YRNA, lncRNA and circRNA. In this review we focus on the emerging potential for these different classes of RNA as cancer biomarkers, and in particular the barriers and limitations that remain to be overcome if these molecules are to become part of routine clinical practice.