[Assessment of setup errors of IGRT combined with a six degrees of freedom bed for patients with primary rectal cancer]

Objective: To investigate the effect of six degree of freedom (6-DOF) bed combined with cone beam computed tomography (CBCT) in the on-line correction of setup errors in patients with primary rectal cancer. Methods: The clinicopathological data of 17 patients with primary rectal cancer in Department of Radiotherapy, Third Hospital of Peking University from July 2013 to January 2014 were collected. There were 14 males and 3 females, a median age of 65 years. The difference of CBCT and 6-DOF bed combined with CBCT online correction of patients with positioning error were retrospectively analyzed. Results: Before position correction, the first CBCT verification of setup errors in the three translation directions including X (left and right), Y (in and out) and Z (up and down) directions were (0.06±0.25) cm, (0.13±0.40) cm and (-0.28±0.31) cm, respectively. The setup errors of RX (rotation pitch), RY(rolling) and RZ (left and right rotation) directions were (0.62±1.15)°, (-0.19±0.99)°, and (-0.34 ± 0.84)°, respectively . After correction of IGRT combined with six freedom of bed, the setup errors of translation X, Y and Z were (0.01±0.09) cm, (-0.01±0.05) cm and (-0.03±0.08) cm, respectively, and the setup errors of rotation RX, RY and RZ directions were (-0.16±0.40)°, (0.36±0.31)°and (-0.01±0.25)°, respectively. There were significant differences in translation direction (X, Y and Z direction) and rotation direction (Rx, RY and RZ) before and after 6-DOF bed combined with CBCT correction (all P<0.05). In the translation direction, the higher frequency range of Z-direction error value was 0.20-0.79 cm. In the rotation direction, the frequency range of error in Rx direction was 0.20°-2.99°. There was no significant difference between bone mode and gray scale model registration (P>0.05). With the progress of radiotherapy, the setup errors of X, Z, Rx, RY and RZ directions increased except Y direction. Conclusions: In radiotherapy, six freedom bed combined with CBCT is helpful to correct the setup errors of patients with primary rectal cancer. Six freedom bed may be used to correct the setup errors of patients with primary rectal cancer online. Image-guided radiation therapy (IGRT) is recommended for bone pattern registration in patients with rectal cancer.

Two novel venom proteins underlie divergent parasitic strategies between a generalist and a specialist parasite

Parasitoids are ubiquitous in natural ecosystems. Parasitic strategies are highly diverse among parasitoid species, yet their underlying genetic bases are poorly understood. Here, we focus on the divergent adaptation of a specialist and a generalist drosophilid parasitoids. We find that a novel protein (Lar) enables active immune suppression by lysing the host lymph glands, eventually leading to successful parasitism by the generalist. Meanwhile, another novel protein (Warm) contributes to a passive strategy by attaching the laid eggs to the gut and other organs of the host, leading to incomplete encapsulation and helping the specialist escape the host immune response. We find that these diverse parasitic strategies both originated from lateral gene transfer, followed with duplication and specialization, and that they might contribute to the shift in host ranges between parasitoids. Our results increase our understanding of how novel gene functions originate and how they contribute to host adaptation.

The complete mitochondrial genome of Leptopilina syphax (Hymenoptera: Figitidae)

Leptopilina syphax (Hymenoptera: Figitidae) is a newly recorded species of parasitic wasp, and it attacks the larval stage of Drosophilidae, mainly the Drosophila species. Few works have been done in the basic study of L. syphax, including the data of mitochondrial genome. In this study, the complete mitochondrial genome of L. syphax (GeneBank accession number: MT649407) was sequenced using Illumina HiSeq X Ten system. The mitochondrial genome is 15,882bp long and comprises 13 protein-coding genes, 2 ribosomal RNA genes and 22 transfer RNA genes. Meanwhile, 26 genes are in majority strand, and the remaining 11 genes are in minority strand. The overall base composition is 41.7% for A, 6.0% for G, 13.6% for C, and 38.7% for T, with an A + T content of 80.4%, respectively. We also performed a phylogenetic analysis with other known mitochondrial genomes of some parasitic wasps. The results show that L. syphax is closely related to L. boulardi, which is another Drosophila parasitoid.

Childhood Secondhand Smoke Exposure and Risk of Dementia, Alzheimer's Disease and Stroke in Adulthood: A Prospective Cohort Study

BACKGROUND

This study aimed to investigate the associations between secondhand smoke exposure and dementia, Alzheimer's disease (AD) and stroke.

METHODS

This prospective study analyzed Framingham Offspring (FHS-OS) cohort participants with parents in the original Framingham Heart Study (FHS) cohort with known smoking status during offspring childhood. Surveillance for incident events, including dementia and stroke, among offspring participants exposed to parental smoking up to the age of 18 years commenced at examination 9 through 2014 and continued for approximately 30 years.

RESULTS

At baseline, a total of 1683 (56.2%) subjects were not exposed to any secondhand smoke, whereas 670 (22.4%) subjects were exposed to 0-1 packs (20 cigarettes)/day, and 640 (21.4%) were exposed to over 1 pack/day. On follow-up (median: 31 years), 2993 patients developed dementia, including 103 with AD dementia and 315 with stroke. After adjusting for a wide range of established risk factors, participants with the highest exposure to secondhand smoke exhibited increased risks of all dementia, AD dementia and stroke compared with individuals with no exposure [HR 2.86 (2.00-4.09) for dementia; HR 3.13 (1.80-5.42) for AD dementia; HR 1.89 (1.37-2.61) for stroke]. The results remained comparable in the subgroup for individuals with median exposure to secondhand smoke.

CONCLUSION

Exposure to secondhand smoke may be associated with increased risks of dementia, AD dementia and stroke.

[Epidemiological characteristics of imported COVID-19 cases in Guangzhou]

Objective: To understand the epidemiological characteristics of imported COVID-19 cases in Guangzhou and provide scientific basis for the prevention and control of the disease. Methods: The data of imported COVID-19 in Guangzhou reported as of April 1, 2020 were collected from National Notifiable Disease Report System of China. The software Excel 2010 and SPSS 19.0 were applied for data cleaning and statistical analysis. Results: As of April 1, 2020, a total of 103 imported COVID-19 cases had been reported in Guangzhou, in which 92 were confirmed cases and 11 were asymptomatic infection cases. The number of the confirmed imported cases accounted for 11.4% (92/806) in of the total in China at the same time. The male to female ratio of the cases was 1.58∶1 (63∶40). The median age of the cases was 31 years (P(25)-P(75):22-40 years), range of age was 11-63 years. The main occupational distributions of the cases were business services (41/103, 39.8%) and students (36/103, 35.0%). The imported cases whose destinations were 19 provinces and municipalities rather than Guangdong after entering the country accounted for 43.7%. The main source countries of infections were the United Kingdom (27/103, 26.2%), the Philippines (13/103, 12.6%), the United States (13/103, 12.6%) and Nigeria (7/103, 6.8%). There were 34 inbound flights from which the imported COVID-19 cases were detected, in which 10 flights (10/34, 29.4%) were found to carry more than 3 cases, with an average voyage time of (11.14±0.53) hours. A total of 29 imported cases(28.2%) showed symptoms before entering the country, and 65 cases (63.1%) had been isolated before the onset of the disease. The mean free activity time of the isolated cases after the onset was (6.76±0.79) days. The average number of the imported cases' close contacts was 53. There were 13 clusters of COVID-19 caused by the imported cases, involving 36 cases (including 1 imported associated case). Conclusions: The sources of the imported COVID-19 cases in Guangzhou were widely distributed, and no cases had been found to be infected on the flights. In the early stage of the imported epidemic, there was high risk for the spread of the epidemic. Strengthened prevention and control of imported COVID-19 effectively reduced the of transmission risk of COVID-19 in communities.

Haplotype of receptor for advanced glycation end products is associated with arterial stiffness in essential hypertension

Background

What causes us to age has been extensively explored. The receptor for AGEs (RAGE) expression is up-regulated in atherosclerotic plaques and its activation leads to oxidative stress, cytokine and adhesion molecule formation, activation of nuclear factor-κB and cell apoptosis. We hypothesized that genetic variation in the RAGE receptor may be associated with arterial stiffness.

Methods

309 untreated hypertensive subjects were tested for genotypes of –374T&gt;A and –429T&gt;C polymorphisms with polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP). Arterial stiffness was measured as pulse wave velocity (PWV), augmentation index (AIx) and central aortic blood pressure (BP). Data was analysed using JMP Version 13 (SAS for Windows).

Results

Both polymorphisms were in Hardy-Weinberg equilibrium. The –374A A allele carriers had significantly lower aortic systolic BP (143±2 vs. 154±1, p&lt;0.001) while –429C allele carriers had lower aortic systolic BP (151±1 vs. 157±2, p&lt;0.01) compared with T carriers. –429C allele carriers had lower PWV compared to 429TT individuals (8.86±1 vs. 10.70±2.5). –374A allele carriers had lower PWV compared to 374TT individuals (9.7±1.43 vs. 10.65±2.6). Subjects with the AC haplotype had the lowest and those with the TT haplotype the highest PWV and aortic BP than any of the other haplotypes containing one or more of the at-risk alleles.

Conclusions

The combined effect of the two genotypes was additive with AA homozygotes of –374T&gt;A and C allele carriers of –429T&gt;C and the haplotype AC, associated with lowest aortic BP and arterial stiffness.

PWV & RAGE haplotypes

Funding Acknowledgement

Type of funding source: None

Gastric cancer nodal tumour-stroma ratios influence prognosis

This study showed that nodal tumour-stroma ratio (NTSR) is an independent prognostic factor for overall and disease-free survival of patients with gastric cancer. Both relative stroma-rich primary tumour-stroma ratio (PTSR) and NTSR were independent negative prognostic factors for overall survival in gastric cancer. This study supports assessment of tumour-stroma ratio in the routine pathological diagnosis of gastric cancer. validated in node-positive disease.

Positron Emission Tomography-Computed Tomography Surveillance after (Chemo)Radiotherapy in Advanced Head and Neck Squamous Cell Cancer: Beyond the PET-NECK Protocol

AIMS

To evaluate the implementation of 18-fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET-CT) surveillance after (chemo)radiotherapy, to compare outcomes for those who achieved a complete (CR), equivocal (EQR) and incomplete (ICR) nodal response on 12-week PET-CT according to their human papillomavirus (HPV) status, and to assess the safety of ongoing surveillance beyond 12 weeks in the HPV-positive EQR group.

MATERIALS AND METHODS

All patients with node-positive head and neck squamous cell carcinoma (HNSCC) treated with (chemo)radiotherapy between January 2013 and September 2017 were identified. PET-CT responses were classified as CR, ICR or EQR. Patient outcomes were obtained from electronic records.

RESULTS

In total, 236 patients with a minimum of 2 years of follow-up were identified. The mean age was 59 years; 79.3% had N2 disease; 77.1% of patients had oropharyngeal cancer and 10.1% had squamous cell carcinoma of unknown primary, of whom 82.0% (169) were HPV positive; 78.0% received chemoradiotherapy. The median time from the end of radiotherapy to PET-CT was 91 days. Of the HPV-related HNSCC, 60.4% achieved CR, 29.0% EQR and 10.6% ICR. With a median follow-up of 41.7 months, there was no difference in survival between patients with HPV-related HNSCC achieving CR and EQR (median overall survival not reached for both, P = 0.67) despite the omission of immediate neck dissection in 98.0% of the EQR group.

CONCLUSION

Patients with HPV-positive HNSCC who have achieved EQR have comparable survival outcomes to those who achieved a CR despite the omission of immediate neck dissections; this shows the safety of ongoing surveillance beyond 12 weeks in this group of patients.

HOXD-AS1: a novel oncogenic long intergenic non-coding RNA in humans

OBJECTIVE

Long non-coding RNAs are an emerging special class of regulatory RNAs with more than 200 nucleotides that play vital roles in gene regulation, metabolism, drug resistance, cell differentiation, and other processes. These RNAs were also reported to be dysregulated in human disease, especially malignant tumors. However, the underlying mechanisms remain elusive. HOXD cluster antisense RNA 1 (HOXD-AS1), a recently discovered long non-coding RNA, is overexpressed in many cancers. We now review recent advances in understanding the function, role, regulation, and oncogenic properties of HOXD-AS1.

MATERIALS AND METHODS

A systematic literature review in PubMed of HOXD-AS1 and cancer-related articles in English, published until June 2018, was conducted.

RESULTS

The literature suggests that HOXD-AS1 is an oncogene that regulates diverse physiological and cellular processes such as proliferation, apoptosis, migration, invasion, metastasis, chemoresistance, epithelial to mesenchymal transition, and stem cell formation by interacting with various regulatory proteins and sequestering several microRNAs such as miR-608, miR-130a, and miR-217.

CONCLUSIONS

HOXD-AS1 may be a prognostic biomarker and potential therapeutic target for various tumor diagnosis and treatment.

MiR-126-3p suppresses the growth, migration and invasion of NSCLC via targeting CCR1

OBJECTIVE

MicroRNA (miRNA) plays vital roles in the development of different cancers. In the current work, we explored the function of miR-126-3p in the growth and metastasis of non-small-cell lung cancer (NSCLC) cell in vitro and in vivo.

PATIENTS AND METHODS

The expressions of miR-126-3p in NSCLC cell lines were assessed using the quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) assay. 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT), colony formation, wound healing and transwell invasion were applied to reveal the role of miR-126b-3p on NSCLC cell growth, migration and invasion. The expressions of epithelial-mesenchymal transition (EMT) associated markers (E-cadherin and N-cadherin) were assessed by immunofluorescence staining. The Xenograft model and lung metastasis model were applied to explore the impact of miR-126-3p on the growth and aggressiveness of NSCLC cell in vivo.

RESULTS

MiR-126-3p was significantly down-regulated in NSCLC cell lines and tissues. The up-regulation of miR-126-3p inhibited the growth, colony formation, migration and invasion of NSCLC cell. Furthermore, the xenograft model indicated that miR-126-3p suppressed NSCLC cell growth and lung metastasis by targeting chemokine (C-C motif) receptor 1 (CCR1). In addition, we demonstrated that the over-expression of CCR1 rescued the inhibitory effects of miR-126-3p on NSCLC cells growth, migration and invasion. Finally, knocked-down of CCR1 was able to mimic the inhibitory effects of miR-126-3p on the progression of NSCLC cell.

CONCLUSIONS

These findings indicate that miR-126-3p plays an important role in the growth, migration and invasion of NSCLC by targeting CCR1.

Leiomyosarcoma After Liver Transplantation Is Unrelated to Epstein-Barr Virus: A Case Report

BACKGROUND

De novo malignancy is a severe complication after liver transplantation (LT), but de novo leiomyosarcoma is extremely rare.

METHODS

We reported de novo leiomyosarcoma occurring after LT. The patient's status for Epstein-Barr virus was negative. The donor was a 21-year-old man with a central nervous system malignancy who underwent surgery. Three months later brain death occurred and his organs were donated.

RESULTS

Leiomyosarcoma in the recipient was detected shortly after LT. It progressed after minimization of immunosuppression and apatinib therapy, and the patient died of cachexia 17 months after LT.

CONCLUSIONS

De novo leiomyosarcoma is a rare but serious event after LT, needing comprehensive management.

The complete mitochondrial genome of Trichopria drosophilae (Hymenoptera: Diapriidae)

Trichopria drosophilae (Hymenoptera: Diapriidae) is an important pupal endoparasitoid of Drosophila species, which has been found to be an ideal biocontrol agent to D. suzukii. In this study, the complete mitochondrial genome of T. drosophilae (GeneBank accession number: MN966974) was sequenced using Illumina HiSeq X Ten system. The mitochondrial genome is 16,375 bp long and comprises 13 protein-coding genes, 22 transfer RNA genes and 2 ribosomal RNA genes. Among them, 24 genes are in majority strand, while the others are in minority strand. The nucleotide composition of A, G, C, T is 44.9%, 6.4%, 5.6%, 43.2% respectively. We also performed a phylogenetic analysis with other known mitochondrial genomes within four families that have been shown to parasitize drosophilid species. The result shows that T. drosophilae is closely related to Ismarus sp.

[Impact of gender on hepatic pathology and antibody - mediated immunity caused by Schistosoma japonicum infection in C57BL/6 mice]

OBJECTIVE

To investigate the effect of gender on hepatic pathology and antibody-mediated immunity in Schistosoma japonicum-infected C57BL/6 mice.

METHODS

Female and male C57BL/6 mice were infected with S. japonicum, and the hepatic pathological changes were observed using HE and picrosirius red staining in mice 8 weeks post-infection. The serum specific IgG antibody levels against the soluble adult worm antigen (SWA) and soluble egg antigen (SEA) were measured in mice using enzyme-linked immunosorbent assay (ELISA), and the percentages of follicular helper T (Tfh) cells and regulatory T (Treg) cells were detected in mouse spleen and lymph nodes using flow cytometry.

RESULTS

HE staining showed no significant difference in the mean area of a single hepatic egg granuloma between female and male mice 8 weeks post-infection with S. japonicum [(28.050 ± 3.576) × 10⁴ μm² vs. (26.740 ± 4.093) × 10⁴ μm²; t = 0.241, P = 0.821], and picrosirius red staining revealed no statistical differences between female and male mice in terms of the mean proportion of picrosirius red stained hepatic tissues [(7.667 ± 1.856)% vs. (7.667 ± 1.764)%; t = 0, P = 1] or the mean optical density [(0.023 ± 0.003) vs. (0.027 ± 0.007); t = 0.447, P = 0.678]. ELISA detected no significant differences in the serum IgG antibody levels against SWA [(2.098 ± 0.037) vs. (1.970 ± 0.071); t = 1.595, P = 0.162] or SEA [(3.738 ± 0.039) vs. (3.708 ± 0.043); t = 0.512, P = 0.623] between female and male mice 8 weeks post-infection with S. japonicum. Flow cytometry detected significantly greater percentages of Tfh cells in the spleen [female mice, (8.645 ± 1.356)% vs. (1.730 ± 0.181)%, t = 5.055, P = 0.002; male mice, (8.470 ± 1.161)% vs. (1.583 ± 0.218)%, t = 5.829, P = 0.001] and lymph nodes [female mice, (3.218 ± 0.153)% vs. (1.095 ± 0.116)%, t = 11.040, P < 0.001; male mice, (3.673 ± 0.347)% vs. (0.935 ± 0.075)%, t = 8.994, P = 0.001) of both female and male mice 8 weeks post-infection with S. japonicum than in uninfected mice; however, no significant differences were seen between female and male mice 8 weeks post-infection with S. japonicum in terms of the percentages of Tfh cells in the spleen [(8.645 ± 1.356)% vs. (8.470 ± 1.161)%; t = 0.098, P = 0.925] or lymph nodes [(3.218 ± 0.153)% vs. (3.673 ± 0.347)%; t = 1.332, P = 0.241]. There was no significant difference in the proportion of Treg cells in the spleen of male mice between infected and uninfected mice [(10.060 ± 0.361)% vs. (10.130 ± 0.142)%; t = 0.174, P = 0.867], while a higher proportion of Treg cells was seen in the spleen of female mice 8 weeks post-infection with S. japonicum than in uninfected mice [(10.530 ± 0.242)% vs. (9.450 ± 0.263)%; t = 3.021, P = 0.023]. There was no significant difference in the proportion of Treg cells in the spleen between female and male mice infected with S. japonicum [(10.530 ± 0.242)% vs. (10.060 ± 0.361)%; t =1.077, P = 0.323]. In addition, the proportions of Treg cells were significantly greater in the lymph node of S. japonicum -infected female [(17.150 ± 0.805)% vs. (13.100 ± 0.265)%; t = 4.781, P = 0.003] and male mice [(18.550 ± 0.732)% vs. (12.630 ± 0.566)%; t = 6.402, P = 0.001] than in uninfected mice; however, no significant difference was seen between female and male mice 8 weeks post-infection [(17.150 ± 0.805)% vs. (18.550 ± 0.732)%; t = 1.287, P = 0.246].

CONCLUSIONS

There are no gender-specific hepatic pathological changes or antibody-mediated immunity in C57BL/6 mice post-infection with S. japonicum.

Rhythmic change of adipokinetic hormones diurnally regulates locust vitellogenesis and egg development

Adipokinetic hormones (AKHs), the neurohormones synthesized in the insect corpora cardiaca are known to mobilize lipids and carbohydrates for energy-consuming activities including reproduction. However, both inhibitory and stimulatory effects of AKHs on insect reproduction have been reported, and the underlying mechanisms remain elusive. Using the migratory locust, Locusta migratoria, as a model system, we report here that AKHs are expressed in response to rhythmic diel change, and AKH III expression increases markedly at photophase. Diurnal injection of AKH III but not AKH I or AKH II in adult females stimulates vitellogenesis and egg development. In contrast, AKH treatment at scotophase represses female reproduction. RNA interference-mediated knockdown of AKH receptor (AKHR) results in significantly reduced vitellogenin (Vg) expression in the fat body at photophase along with reduced Vg deposition in the ovary. AKHR knockdown also leads to decreased expression of Brummer, triacylglycerol lipase and trehalose transporter, accompanied by suppressed mobilization of triacylglycerol and trehalose. We propose that in addition to stimulating Vg expression at photophase, AKH/AKHR signalling is likely to regulate ovarian uptake of Vg via triacylglycerol mobilization and trehalose homeostasis. This study provides new insights into the understanding of AKH/AKHR signalling in the regulation of insect reproduction.

[Study on immunological functions of heat shock protein 40 kDa of Schistosoma japonicum]

OBJECTIVE

To investigate the immunological functions of heat shock protein 40 kDa of Schistosoma japonicum (SjHSP40).

METHODS

The homology of the SjHSP40 protein sequence was analyzed and the B and T cell epitopes of SjHSP40 were predicted using bioinformatics tools. The full-length SjHSP40 gene was amplified using a PCR assay, and cloned into the prokaryotic expression vector pGEX-6P-1, which was transformed into Escherichia coli BL-21. The protein expression was induced with isopropyl β-D-thiogalactoside (IPDG), and then, the recombinant protein was purified with glutathione-sepharose 4B resin to yield the fusion protein GST-SjHSP40, which was checked with SDS-PAGE and Western blotting. Following immunization with GST-SjHSP40, the serum levels of anti-SjHSP40 IgG antibody and IgG1 and IgG2a subtypes were detected in BALB/c mice using ELISA. In addition, the effect of SjHSP40 on CD4⁺ T-cell subset differentiation was examined using flow cytometry.

RESULTS

SjHSP40 contained 7 potential B cell epitopes and multiple T cell epitopes (CTL epitopes and Th epitopes). The prokaryotic expression plasmid pGEX-6p-1-SjSHP40 was successfully constructed, and the fusion protein GST-SjHSP40 was obtained following IPDG induction and protein purification. Significantly higher serum levels of anti-SjHSP40 IgG, IgG1 and IgG2a antibodies were detected in mice immunized with GST-SjHSP40 than in other groups; however, SjHSP40 showed no remarkable effects on CD4⁺ T-cell subset differentiation.

CONCLUSIONS

SjHSP40 may induce specific humoral immune responses in mice; however, it does not affect the balance of Th immune responses. It is suggested that SjHSP40 may be a potential vaccine candidate.

Biological background of the genomic variations of cf-DNA in healthy individuals

BACKGROUND

Cell-free DNA (cf-DNA)-based liquid biopsy is emerging as a revolutionary new method in individualized cancer treatment and prognosis monitoring, although detecting early-stage cancers using cf-DNA remains challenging, partially because of the undefined biological background of cf-DNA.

MATERIALS AND METHODS

We investigated somatic mutations in the cf-DNA of 259 cancer-free individuals with a median age of 47 years using an endogenous barcoding duplex method with an ultralow base error rate (2 × 10-7) and compared the variant allele frequencies (VAFs) of these mutations between the cf-DNA and the corresponding blood cell DNA.

RESULTS

Sixty percent (155/259) of the samples showed at least one nonsynonymous mutation on either of two similar target panels covering 508 and 559 cancer-related genes. For individuals older than 50 years of age, the positive rate increased to 76%. Most cf-DNA mutations were also present at similar VAFs in the paired blood cell DNA. The most frequently mutated genes were driver genes of hematologic malignancies, including DNMT3A, TET2, AXSL1, and JAK2. However, the other 58.4% (192/329) of the mutations were likely 'passenger mutations' of clonal hematopoiesis, including mutations in NOTCH2, FAT3, EXT2, ERBB4, and ARID2, which are driver genes of solid tumors.

CONCLUSION

Hematopoietic clone-derived mutations, including 'driver mutations' and 'passenger mutations', are prevalent in the cf-DNA of both healthy individuals and cancer patients and may be a potential source of false positives in the liquid biopsy. Our results also suggest the ineffectiveness for distinguishing clonal hematopoietic mutations of low VAF (≤0.1%) from tumor-derived mutations using conventional next-generation sequencing of blood cell DNA. However, an error correction model with an ultralow error rate and high coverage depth is required for blood cell DNA sequencing, which is difficult and costly to achieve with current technologies.