- Academic Editor
†These authors contributed equally.
The incidence and mortality from malignant tumors continue to rise each year. Consequently, early diagnosis and intervention are vital for improving patient’ prognosis and survival. The traditional pathological tissue biopsy is currently considered the gold standard for cancer diagnosis. However, it suffers from several limitations including invasiveness, sometimes not repeatable or unsuitable, and the inability to capture the dynamic nature of tumors in terms of space and time. Consequently, these limit the application of tissue biopsies for the diagnosis of early-stage tumors and have redirected the research focus towards liquid biopsies. Blood-based liquid biopsies have thus emerged as a promising option for non-invasive assessment of tumor-specific biomarkers. These minimally invasive, easily accessible, and reproducible tests offer several advantages, such as being mostly complication-free and efficient at monitoring tumor progression and tracing drug resistance. Liquid biopsies show great potential for cancer prediction, diagnosis, and prognostic assessment. Circulating tumor-educated platelets (TEPs) possess the unique ability to absorb nucleic acids from the bloodstream and to modify transcripts derived from megakaryocytes in response to external signals. In addition, circulating free RNA (cfRNA) constitutes a significant portion of the biomolecules present in the bloodstream. This paper aims to provide a comprehensive overview of the current research status regarding TEP RNA and cfRNA in liquid biopsies from various tumor types. Our analysis includes cancers of the lung, liver, pancreas, breast, nasopharynx, ovary and colon, as well as multiple myeloma and sarcoma. By synthesizing this information, we intend to establish a solid theoretical foundation for exploring potential applications of circulating RNA as a reliable biomarker for tumor diagnosis and monitoring.
Cancer, or malignant neoplasm, is associated with high global incidence and mortality rates. There has been a worrisome surge in cancer incidence over the past 6 years, with approximately 4 million new cases and 1.4 million deaths [1, 2]. Traditional tissue biopsy serves as the gold standard for tumor diagnosis. However, it is limited by its invasiveness, high risk, potential complications, and lack of reproducibility and applicability in certain cases [3, 4, 5, 6]. Tissue biopsies are also unable to capture dynamic information on tumor development and epigenetic characteristics [7], thereby restricting their overall applicability. The limitations inherent with tissue biopsy have led the oncology field to shift its research focus towards the assessment of circulating components in the blood [8]. This approach, known as blood-based “liquid biopsies”, offers numerous advantages including being minimally invasive, easily accessible, reproducible, and free from potential complications. Moreover, liquid biopsies are efficient at monitoring disease progression and tracking tumor drug resistance. They have been extensively studied and found to be a viable alternative for the noninvasive assessment of tumor-specific biomarkers [9].
As a minimally invasive method for cancer detection and monitoring, liquid biopsy has the potential to revolutionize cancer diagnosis. It allows for comprehensive and precise analysis of tumors and their microenvironment at multiple levels. The careful application of liquid biopsies enables earlier detection of cancer development, prognostic evaluation of tumors at various stages, and the identification of novel targets for personalized treatment. Furthermore, blood tests can be utilized for pre-treatment tumor classification, thereby allowing enabling personalized treatment, early intervention, treatment response monitoring, regular assessment of treatment efficacy, and the follow-up and early detection of disease recurrence. Currently, researchers are investigating the different components of the blood in various cancer types (Fig. 1). Amongst these, significant attention has been focused on biomolecules such as circulating tumor DNA/RNA (ctDNA/ctRNA) and circulating cell-free DNA/RNA (cfDNA/cfRNA), as well as circulating tumor cells (CTCs), extracellular vesicles (including exosomes and tumor vesicles), and tumor-educated platelets (TEPs). These hold immense value for early tumor diagnosis and for the assessment of treatment efficacy [10].
Peripheral Blood Cells Isolation by Density Gradient Centrifugation. ctDNA/RNA, circulating tumor DNA/RNA; cfDNA/RNA, circulating cell-free DNA/RNA.
Platelets are small cell fragments shed from the cytoplasm of mature megakaryocytes resident in the bone marrow, and comprise an important component of the blood [11]. In addition to their well-known functions in thrombosis and hemostasis regulation, platelets also play a vital role in the immune system. They are actively involved in both innate and adaptive immune responses, and contribute to various processes such as atherosclerosis, angiogenesis, and lymphatic vessel development [12]. The interaction between tumor cells and circulating platelets has been implicated in tumorigenesis, angiogenesis, tumor spread, and metastasis [13]. Platelets can influence the development and progression of cancer through several mechanisms [14, 15, 16]. Firstly, they can aggregate around tumors, thereby promoting tumor growth and evading immune elimination. Secondly, they facilitate the adhesion of tumor cells, allowing them to evade killing by the immune response. Thirdly, the activation of platelets promotes tumor cell invasion and metastasis through various processes, including the synthesis of lipid products [17], release of proteins from alpha granules [18], induction of epithelial-mesenchymal transition (EMT) [19], angiogenesis, and facilitating the resistance and extravasation of tumor cells [20]. On the other hand, platelet activation functions rely on tumor cells to induce changes in the transcriptome profile of platelets [21]. This can occur directly through the transfer of tumor-derived RNA [22], or indirectly through the release of signals that regulate platelet mRNA processing [23]. In the presence of tumor cells and the tumor microenvironment (TME), these changes lead to the conversion of immature platelet mRNAs into mature mRNAs that are subsequently translated into functional proteins, ultimately resulting in the generation of tumorigenic platelets. Sequencing analysis of mRNA from TEPs has revealed a remarkable potential to differentially diagnose limited and metastatic tumors with an accuracy of 96%. Additionally, sequencing of mRNA from TEPs could identify the primary tumor location of six distinct tumor types with an accuracy of 71% [24]. Of note, miRNAs are the most widely studied of the various RNA types. These small non-coding RNA molecules are typically 19 to 24 bases in length and play a crucial role in the post-transcriptional regulation of gene expression. They can sometimes behave as either oncogenes or tumor suppressor genes, and exert their regulatory influence over various cellular pathways with remarkable stability [25]. This stability may be due to the protective effects of miRNA within exosomes and/or protein complexes. It is worth noting that miRNAs are not only the most abundant RNA species in peripheral blood, but also the predominant RNA species found in TEP-derived RNA [21, 22, 23, 24, 25, 26].
In summary, platelets are involved in cancer development and progression, making them a promising source of biomarkers. In this paper, we review the current research status on TEP-RNAs in various cancer types. Additionally, we explore potential applications of TEP RNA in early cancer diagnosis, prognosis, and treatment, and offer insights into its future prospects as a biomarker. The investigation of cfRNA derived from plasma or serum has also attracted significant attention in recent years. The extraction and isolation methods for cfRNA and platelets are similar [27] and will be comprehensively reviewed in this paper (Supplementary Table 1). The application of platelets and cfRNA in cancer research is therefore very promising, and more in-depth studies should reveal their full potential in cancer diagnosis, treatment and prognosis.
TEP RNA and cfRNA have recently received considerable attention in the liquid biopsy field. They are considered to be potential tumor biomarkers due to their high stability and detectability. The continuous development of experimental techniques such as microarray sequencing and quantitative real-time polymerase chain reaction (qRT-PCR) has enabled in depth analysis of circulating RNA, including investigation of its potential roles in tumorigenesis, progression and prognostic assessment. Currently, this field of oncology research is undergoing rapid development. The current paper synthesizes the latest scientific findings and summarizes the current status of research on TEP RNA and cfRNA in different tumor types including lung, liver, pancreatic, breast, nasopharyngeal, ovarian, colorectal, multiple myeloma and sarcoma. Our aim is to provide an essential reference that allows a deeper understanding of circulating RNA and facilitates its application as a potential tumor biomarker.
Lung cancer (LC) is one of the most common malignancies worldwide, with rising incidence and mortality rates in recent years. According to the World Health Organization (WHO), there were approximately 18.1 million new cancer cases and 9.6 million cancer-related deaths worldwide in 2018. Of these, 2.09 million (11.5%) of all new cancers were LC, while 1.76 million (18.3%) of all cancer-related deaths were from LC [28]. Approximately 934,700 new cases of LC were reported in China in 2016, representing an incidence of 73.48 per 100,000 individuals. Additionally, there were approximately 440,500 deaths, resulting in a death rate of 56.82 per 100,000 individuals [29]. LC is now the leading cause of cancer-related death in men worldwide, and the second leading cause in women [30]. The histopathological subtypes of LC are classified as small cell LC and non-small cell LC (NSCLC). The latter accounts for the majority (85%) of cases and includes squamous cell carcinoma, adenocarcinoma, and large cell carcinoma [31]. Early-stage LC may show mild or even no typical clinical manifestations. Consequently, the majority of patients are diagnosed at an advanced stage, with the presence of lymph node or distant metastases. This adversely affects both the treatment outcomes and prognosis of LC [32]. Therefore, establishing early diagnosis and implementing timely interventions has major significance for disease progression and prognosis. At present, LC diagnosis relies primarily on a combination of clinical manifestations, diagnostic imaging, biochemical tests, and histopathological analysis. The biomarkers carcinoembryonic antigen (CEA), cancer antigen 125 (CA125) and cytokeratin 19 fragment (CYFRA21-1) are widely used in the detection and diagnosis of LC, but are more accurate for the diagnosis of advanced LC rather than early LC [33]. Meanwhile, molecular diagnostics is gradually improving and showing increasingly advantageous features [27]. Among these methods, the molecular expression profile of cancer samples show good potential for cancer classification. However, classical molecular diagnostic tests are limited by the availability of tissue samples and are somewhat hindered in clinical practice by time and space constraints. The development of liquid biopsies has addressed these problems very well. In the subsequent section, we provide a comprehensive review of TEP RNA and cfRNA in the context of LC research.
Li et al. [32] utilized lncRNA microarrays to investigate the potential
diagnostic value of TEP RNA in LC. They found that the expression levels of the
TEP lncRNAs GTF2H2-1 and RP3-466P17.2 in LC patients were significantly lower
than in the healthy population, whereas the levels of TEP lncRNA ST8SIA4-12 was
significantly higher (p = 0.0001). Similar differences were observed
between individuals with early-stage LC and the normal population. To further
investigate the accuracy of TEP RNA for LC diagnosis, the researchers constructed
receiver operating characteristic (ROC) curves. TEP lnc-GTF2H2-1, RP3-466P17.2
and ST8SIA4-12 showed good performance as biomarker complexes for the diagnosis
of LC, with a combined area under the curve (AUC) of 0.921, sensitivity of
82.6%, and specificity of 87.1%. Additionally, these biomarker complexes showed
promising diagnostic potential for early-stage LC, with a combined AUC of 0.895,
sensitivity of 93.6%, and specificity of 69.8%. Furthermore, TEP linc-GTF2H2-1
had the ability to distinguish between patients with early- and advanced-stage
LC. When combined with other biomarkers such as CEA, CYFRA21-1, and
neuron-specific enolase (NSE), the diagnostic performance of TEP linc-GTF2H2-1
for distinguishing between intermediate and advanced stages was significantly
enhanced (AUCs of 0.799, 0.806, and 0.790, respectively). The results were
significantly better than those of each biomarker alone (AUCs of 0.780, 0.797 and
0.773, respectively). Lastly, the combination of these four biomarkers resulted
in a notable improvement in LC diagnosis (AUC of 0.899, sensitivity of 76.6%,
and specificity of 85.0%), thus further emphasizing the potential role of TEP
RNA in tumor diagnosis and assessment of disease progression. Another study used
a similar approach to investigate the levels of Apoptotic Chromatin Condensation
Inducer 1 (ACIN1) mRNA in platelets derived from 146 LC patients and 58 healthy
individuals [33]. The level of ACIN1 mRNA was found to be significantly higher in
platelets from LC patients compared to platelets from healthy controls (p = 0.015). Moreover, ROC curve analysis for LC detection showed a sensitivity of
82.7%, specificity of 44.8%, accuracy of 0.724, and AUC of 0.608. The ACIN1
mRNA level was not significantly correlated with age, sex, type of pathology, or
presence of metastasis (p
Researchers have also focused on the role of cfRNA in the diagnosis and treatment of tumors, with studies showing that both quantitative and qualitative analysis of cfRNA can guide the selection of treatment options and monitor treatment efficacy [36]. Furthermore, cfRNA has broader applications compared to TEP RNA since it encapsulates a range of information, including the transcriptome of cancer cells, mutational data, and epigenetic regulatory information [37]. Hence, further in-depth studies on the application of cfRNA for early diagnosis, prognostic assessment and monitoring treatment response in LC appear warranted.
The miR-21 microRNA has been linked to various cancer types, including NSCLC
[38], liver cancer [39], and pancreatic cancer [40]. Significantly higher miR-21
levels were observed in the plasma of NSCLC patients compared to controls
(p
These findings also highlight the potentially important role of serum RNA in the diagnosis and treatment of cancer, particularly for early detection and prognostic evaluation. It has been reported that serum RNA is accurate and sensitive for the detection of LC metastases, even before these are visible on imaging scans [35]. Serum RNA offers several advantages over tissue biopsy, including non-invasiveness and better visualization of tumor heterogeneity, gene alterations, and clonal evolution, as well as providing a comprehensive view of tumor dynamics [42, 43]. In addition, the evaluation of serum RNA, is very convenient for the monitoring of tumor drug resistance and targeted therapy [44]. Moreover, the postoperative management of cancer patients can be optimized by monitoring tumor burden and detecting minimal residual disease [45]. Further research is needed to validate the possible application of serum RNA in cancer, but these biomarkers have recently become an active area of interest for researchers. They should also help in gaining a better understanding of the mechanisms of cancer development, as well as providing new ideas and approaches for cancer treatment and management.
Primary liver cancer is a prevalent malignancy worldwide, ranking sixth in terms of incidence and second in terms of mortality [46]. It therefore presents a significant threat to human life and well-being. There are approximately 782,000 new cases of hepatocellular carcinoma (HCC) per year worldwide, accounting for 75%–85% of all primary liver cancers [47, 48]. The primary techniques utilized for early, non-invasive detection of HCC include serum alpha-fetoprotein (AFP), ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI). Among these methods, serum AFP and US are the most commonly used diagnostic approaches [49]. Nevertheless, they have a high false-negative rate ranging from 10% to 30%. Hence, there is an urgent need to discover novel indicators with high sensitivity and specificity in order to increase the diagnostic accuracy for early-stage HCC and to facilitate early treatment and improve prognosis. Next, we will review the relevant advances of TEP RNA and cfRNA in HCC research in detail.
Numerous studies have reported that miRNA-122, which is specifically expressed
in the liver, is a key regulator in liver development and liver diseases.
MiRNA-122 is also upregulated in the peripheral circulation of HCC patients.
MiRNA-21 is one of the most prevalent miRNAs in the bloodstream and is present at
high levels in nearly all types of solid cancers [38, 40]. In light of these
findings, researchers have conducted quantitative real-time polymerase chain
reaction (qRT-PCR) assays to assess the diagnostic value of TEP miRNA-122 and TEP
miRNA-21 in HCC [39]. The levels of both were significantly increased in
individuals with liver cancer compared to normal subjects (p
Although great progress has been made in understanding the molecular mechanisms of pancreatic cancer (PC) development, it remains one of the deadliest cancer types. In the absence of new diagnostic methods and/or treatments, PC is expected to become the second leading cause of cancer-related deaths by the end of 2023. Surgical resection is the most effective treatment for PC, but the majority of patients (80–85%) are unable to undergo surgery due to the presence of local invasion and/or distant metastases [56]. Hence, there is an urgent need to develop new biomarkers for the early diagnosis and prognostic assessment of PC in order to enhance the clinical management of these patients [57]. Wang et al. [40] selected four plasma miRNAs (miR-21, miR-210, miR-155 and miR-196a) that are overexpressed in PCs in order to assess their effectiveness as biomarkers. Inhibition of miR-21 was previously found to reduce the proliferation, invasion and migration of pancreatic intraepithelial neoplasia (PanIN) cells in a mouse model, and also to delay the progression of PanIN to PC [58]. Vila-Navarro et al. [59] recently identified a set of 14 miRNAs in plasma that were significantly elevated in the plasma of patients with PC or intraductal papillary mucinous neoplasm (IPMN) compared to healthy controls. These (miRNAs) (let7e-5p, let-7f-5p, miR-103a-3p, miR-151a-5p, miR-151b, miR-16-5p, miR-181a-5p, miR192-5p, miR 21-5p, miR-221-3p, miR-23a-3p, miR-320a, miR-33a-3p and miR-93-5p) have been suggested as potential biomarkers for non-invasive diagnostic procedures in PC, with the combination of miR-33a-3p, miR-320a, and Carbohydrate Antigen 19-9 (CA19-9) showing the highest diagnostic accuracy (AUC = 0.948). Moreover, miR-181b-5p and miR-548d-3p were found to be significantly increased in the plasma of PC patients, but a similar upregulation was not observed in precancerous IPMN patients. These two miRNAs were therefore considered to be potential biomarkers for monitoring the malignant transformation of IPMN, although more prospective validation studies are required before their clinical application. Cao et al. [60] reported that a combination of three plasma miRNAs (miR-486-5p, miR-126-3p, and miR-106b-3p) had an AUC of 0.891 for the differentiation of PC from chronic pancreatitis (CP), thereby surpassing the diagnostic accuracy of CA19-9 (AUC = 0.775). Another study found that the diagnostic value of miR-486-5p alone for differentiating PC patients, CP patients and healthy controls was equivalent to that of CA19-9 [61]. Mazza et al. [62] analyzed three miRNAs (miR-1225p, miR-1273g-3p and miR-6126) overexpressed in PC patients. They found that a combination of plasma miR-1273g-3p with CA19-9 levels could more accurately differentiate PC patients from healthy individuals (AUC = 0.940) compared to miR-1273g-3p alone (AUC = 0.703) and CA19-9 (AUC = 0.906). Plasma miR-181b, miR-196a and miR-210 are reported to have similar properties, and since their levels correlate significantly with lymph node metastasis (p = 0.0010, 0.0008, and 0.0013, respectively), clinical stage (p = 0.0048, 0.0319, 0.0027) and vascular invasion (p = 0.0002, 0.0016, 0.0019), they could be used as prognostic markers [63]. Other investigators have reported that miR-99a-5p, miR-200c-3p, and miR-365a-3p could effectively distinguish PC patients with poor prognosis after resection and those with longer survival times [64].
Breast cancer (BC) is one of the most common and deadly cancers in women
worldwide. The incidence of BC (30%) has surpassed that of LC (13%) as the most
common malignancy in women worldwide [65]. BC is also the leading cause of
cancer-related deaths in the female population, with metastasis and recurrence
being the main causes of mortality [66]. The cure rate for
On the basis of previous findings, researchers have validated changes in the
serum miR-155 level of BC patients [68]. This was significantly increased in BC
patients (p
Nasopharyngeal carcinoma (NPC) is a common malignant tumor of the nasopharynx,
with an annual incidence of 15–50 cases per 100,000 individuals in the southern
region of China and Southeast Asian countries [73]. Similar to other cancer
types, there are numerous challenges in the early diagnosis of NPC. The detection
of DNA and antibodies for Epstein Barr virus (EBV) in the peripheral blood are
commonly used diagnostic methods, but have limitations in terms of their
sensitivity and specificity. Hence, the identification of novel biomarkers is
urgently needed to improve the early detection of NPC. Significantly higher
expression levels of TEP miR-34c-3p and TEP miR-18a-5p were reported in patients
with NPC (p
Ovarian cancer (OC) is the fifth leading cause of cancer death in women and
faces the same challenges of early diagnosis and poor prognosis [76]. Serum
miRNAs have been found to correlate with OC diagnosis and may provide a more
accurate and reliable method of early diagnosis for the benefit of patients.
Among them, miR-200c and miR-141 were effective at distinguishing OC patients
from healthy controls (p
The high incidence of colorectal cancer (CRC) in developing countries and its
poor prognosis [78, 79] have led to an increased focus on the identification of
non-invasive biomarkers for this disease. LncRNAs are non-protein-coding RNA
molecules of
Multiple myeloma (MM) is an incurable malignant hematologic cancer characterized by the clonal growth of plasma cells. The traditional diagnostic method for MM is bone marrow aspiration, but the invasiveness of this procedure and its inability to identify MM heterogeneity are major clinical shortcomings. Although the correlation between TEPs and MM has not been studied in detail, a low mean platelet volume was associated with poor prognosis in MM patients and could therefore be a potential marker of progression and prognosis [87, 88]. The analysis of TEPs in liquid biopsies, may also provide a new method for the diagnosis of MM [89]. Another study recently found that liquid biopsies based on TEP RNA could help in the diagnosis of sarcoma [90].
Although the study of blood-derived biomarkers has shown tremendous progress over the past decade, most of the RNAs identified so far as potential cancer biomarkers have failed to advance from the experimental stage to clinical trials. This is largely due to the limited reproducibility of RNA in blood as a biomarker the instability and low abundance of blood samples, and DNA contamination during specimen processing [91]. Therefore, further optimization of extraction processes and standardized parameter thresholds are needed before blood-related biomarkers can be used for clinical cancer diagnosis [92]. In response to the current limitations of liquid biopsies, researchers have developed ultra-high depth sequencing [93, 94, 95]. This can lower the detection limit to as little as 0.001%, thus significantly increasing the diagnostic sensitivity for various cancer types. Selecting the size of sequenced fragments and constructing libraries based on single strands are also effective methods for increasing assay sensitivity [96]. Recent work has shown that polymer structures can improve the operational performance of biosensors by increasing sensitivity, improved binding, and avoidance of non-specific interactions thereby leading to enhanced specificity. Furthermore, polymer-based materials can greatly increase signal amplification from low-concentration targets in the sample, thereby improving the sensitivity of detection [97]. Targeted balancing of the core assessment metrics in various early cancer screening products also helps to achieve flexible application of liquid biopsy technology [98].
The use of blood-based liquid biopsy as a novel, non-invasive biomarker detection method in recent years has led to revolutionary advances in clinical diagnostic and treatment technologies. By analyzing the presence of bioactive substances and RNA in plasma or serum, liquid biopsy can provide a wealth of diagnostic and testing information for clinical purposes, including early cancer screening, tumor diagnosis and monitoring, and assessment of treatment response. In addition, liquid biopsy technology offers a wide range of applications for the prognostic assessment of diseases and clinical screening of drugs. Some studies have shown that platelet inhibitors, such as aspirin or the P2Y12 inhibitor tegretol, can slow tumor progression and the growth and metastasis of cancer cells by blocking their interaction with platelets, thus improving the progression-free survival of patients [99, 100].
Despite still being an immature field, liquid biopsy is undeniably an important and growing area of investigation. To fully exploit the enormous potential of liquid biopsy for cancer prediction, diagnosis and real-time monitoring, there is an urgent need to address several issues. These include the improvement of blood sample processing and RNA extraction processes, the development of standardized parameter thresholds, and the implementation of clinical trials. This should allow liquid biopsy to become a reliable, accurate and widely used tool for early diagnosis, individualized treatment, and better prognostic assessment of cancer patients.
ACIN1, Apoptotic Chromatin Condensation Inducer 1; AFP, alpha-fetoprotein; AUC, area under the curve; BC, Breast cancer; BCLC, Barcelona Clinic Liver Cancer; CA125, Cancer Antigen 125; CA19-9, Carbohydrate Antigen 19-9; CA15-3, carbohydrate antigen 15-3; CEA, Carcinoembryonic antigen; cfDNA/cfRNA, circulating cell-free DNA/RNA; ChE, cholinesterase; CP, chronic pancreatitis; CRC, colorectal cancer; CT, computed tomography; CTCs, circulating tumor cells; ctDNA, circulating tumor DNA; CYFRA21-1(cytokeratin 19 fragment), Cytokeratin Fragment 21-1; EBV, Epstein Barr virus; EML4-ALK, echinoderm microtubule-associated protein like 4-anaplastic lymphoma kinase; EMT, epithelial-mesenchymal transition; HBV, hepatitis B virus; HCC, hepatocellular carcinoma; IPMN, intraductal papillary mucinous neoplasm; MM, Multiple myeloma; MRI, magnetic resonance imaging; NLR, Neutrophil-to-Lymphocyte Ratio; NPC, Nasopharyngeal carcinoma; NSCLC, non-small cell lung cancer; NSE, neuron-specific enolase; OC, Ovarian cancer; OS, overall survival; PC, pancreatic cancer; PanIN, pancreatic intraepithelial neoplasia; PFS, progression-free survival; qRT-PCR, quantitative real-time polymerase chain reaction; ROC, receiver operating characteristic; TEPs, tumor-educated platelets; TME, tumor microenvironment; TPS, tissue peptide-specific antigen; US, ultrasound; WHO, World Health Organization.
All authors listed in this article have made substantial contributions to the conception or design of the work. HH, HS, BH, JH and HZ were involved in drafting the work and reviewing it critically for important intellectual content, BH was involved the acquisition, analysis, or interpretation of data for the work, and JH and HZ finally approved the version to be released; and agrees to be responsible for all aspects of the work to ensure that issues related to the accuracy or completeness of any part of the work are properly investigated and resolved. All authors read and approved the final manuscript. All authors have participated sufficiently in the work and agreed to be accountable for all aspects of the work.
Not applicable.
Not applicable.
This article was supported by Human Resources and Social Security Department System of Shanxi Province (Grant No.20210001), Research Project Supported by Shanxi Scholarship Council of China (Grant No. 2021-116), Shanxi ‘136’ Leading Clinical Key Specialty (Grant No. 2019XY002), and Shanxi Provincial Key Laboratory of Hepatobiliary and Pancreatic Diseases (under construction).
The authors declare no conflict of interest.
Publisher’s Note: IMR Press stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.