Colorectal cancer is a highly prevalent gastrointestinal malignancy in China. Insufficient early diagnosis and high postoperative recurrence risk represent critical bottlenecks restricting the improvement of patient prognosis. In recent years，the rapid development of non-invasive determination technologies using feces and blood samples has provided new directions and feasible approaches for the early screening，therapeutic efficacy evaluation and overall disease management of colorectal cancer. This review focuses on the advances in combined determination of fecal multi-biomarkers，new serum molecular biomarkers，matrix-assisted laser desorption/ionization time-of-flight mass spectrometry（MALDI-TOF MS）technology，construction of prognostic prediction models and dynamic monitoring of minimal residual disease（MRD）. It systematically summarizes the application progress of non-invasive determination in early screening，diagnosis，prognostic evaluation and recurrence monitoring of CRC，as well as the advantages of current technologies，bottlenecks in clinical application and future research prospects.

Gene testing has been widely applied in the screening，diagnosis，classification，monitoring and treatment of colorectal cancer. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry （MALDI-TOF MS） has gradually become one of the techniques for determining nucleic acid polymorphisms due to its advantages of high throughput，high sensitivity and high determination efficiency. This review briefly describes the origin and development of nucleic acid mass spectrometry，introduces the principle and method of MALDI-TOF MS for nucleic acid determination，and reviews the targets，projects，applications and clinical value of MALDI-TOF MS in colorectal cancer determination.

Objective To investigate the clinical application value of monocyte-to-high-density lipoprotein cholesterol ratio（MHR） in the diagnosis of colorectal cancer（CRC）. Methods A total of 87 patients with CRC（CRC group） and 68 patients with benign colorectal polyps（benign polyp group） from Tongji Hospital of Tongji University from September 2019 to December 2023 were enrolled. The clinical data were collected，and platelet（PLT）count，the absolute value of monocytes，the absolute value of neutrophils，high-density lipoprotein cholesterol（HDL-C），carbohydrate antigen 19-9（CA19-9） and carcinoembryonic antigen（CEA） were determined. The MHR，neutrophil-to-high-density lipoprotein cholesterol ratio（NHR） and lymphocyte-to-high-density lipoprotein cholesterol ratio（LHR）were calculated. Multivariate Logistic regression analysis was used to evaluate the influencing factors of CRC occurrence. A nomogram model was constructed，and its efficacy was evaluated by receiver operating characteristic（ROC） curve，decision curve，calibration curve and Hosmer-Lemeshow goodness-of-fit test. Results The age，PLT count，NHR，MHR，CA19-9 and CEA levels in CRC group were higher than those in benign polyp group（P<0.05）. The HDL-C level and body mass index（BMI） were lower than those in benign polyp group（P<0.05）. Elevated PLT count，MHR and CEA and decreased BMI were independent risk factors for CRC（P<0.05）. A nomogram model was constructed based on PLT count，MHR，CEA and BMI，and the area under curve（AUC） for predicting CRC was 0.852，with a high degree of fit（Hosmer-Lemeshow χ²=2.955，P=0.966）. Within the threshold probability range，the clinical net benefit was >0，and the maximum net benefit value was 0.56. Conclusions The nomogram prediction model based on PLT count，MHR，CEA and BMI has a high clinical efficacy in predicting CRC.

Objective To investigate the role of combined determination of serum soluble B7-homologue 3（sB7-H3），Golgi protein 73（gp73） and tumor-associated trypsinogen-2（TAT-2） in the differential diagnosis of colorectal cancer and tubular adenoma. Methods A total of 86 patients with colorectal cancer（colorectal cancer group），86 patients with tubular adenoma（tubular adenoma group） and 86 healthy subjects（healthy control group） were enrolled from the First Hospital of Handan City from December 2020 to December 2022. The colorectal cancer patients were classified into stage Ⅰ-Ⅱ group（54 cases） and stage Ⅲ-Ⅳ group（32 cases） according to TNM staging. Serum levels of sB7-H3，gp73，TAT-2，carcinoembryonic antigen（CEA） and carbohydrate antigen 19-9（CA19-9） and fecal occult blood status were determined. The efficacy of single and combined determinations of each indicator in differentiating colorectal cancer and tubular adenoma was evaluated using receiver operating characteristic（ROC） curve. Multivariate Logistic regression analysis was used to assess the influencing factors of colorectal cancer occurrence. Results The serum levels of sB7-H3，gp73，TAT-2，CEA and CA19-9 and the proportion of positive fecal occult blood in healthy control group，tubular adenoma group and colorectal cancer group were increased successively（P<0.001）. The serum levels of sB7-H3，gp73，TAT-2，CEA and CA19-9 in stage Ⅲ-Ⅳ group were higher than those in stage Ⅰ-Ⅱ group（P<0.05）. Positive fecal occult blood and elevated CEA，CA19-9，sB7-H3，gp73 and TAT-2 were risk factors for colorectal cancer occurrence（P<0.05）. The areas under curves（AUC） for differentiating healthy control from tubular adenoma and differentiating healthy control from colorectal cancer by single determinations of serum CEA，CA19-9，sB7-H3，gp73 and TAT-2 and their combined determination were 0.701，0.710，0.751，0.754，0.829，0.904，and 0.781，0.758，0.809，0.780，0.798 and 0.900，respectively. The AUC for differentiating colorectal cancer and tubular adenoma were 0.701，0.718，0.730，0.739，0.710 and 0.908，respectively. Conclusions The combined determination of serum sB7-H3，gp73 and TAT-2 can be used as indicators for the differential diagnosis of colorectal cancer and tubular adenoma.

Objective To analyze the dynamic changes of frizzled-6（FZD6） mRNA expression during postoperative chemotherapy in patients with colorectal cancer（CRC） and its predictive value for prognosis. Methods A total of 130 CRC patients who received chemotherapy at Nanjing Jiangbei Hospital from August 2022 to April 2024 were enrolled. They were classified into good prognosis group（89 cases） and poor prognosis group（41 cases） based on their prognosis. The clinical data were collected，and the relative expression level of FZD6 mRNA was determined. Multivariate Logistic regression analysis was used to evaluate the influencing factors of prognosis in CRC patients，and the relationship between FZD6 mRNA expression and prognosis under different clinicopathological characteristics was further analyzed. Multivariate linear regression analysis was used to determine the relationship between FZD6 mRNA expression and immune factor levels. Receiver operating characteristic（ROC） curve and restricted cubic spline model were used to analyze the correlation between FZD6 mRNA expression and prognosis outcomes. Kaplan-Meier survival curve was used to analyze the impact of FZD6 mRNA expression on the survival of CRC patients. Results Compared with good prognosis group，poor prognosis group had higher proportions of tumor size ≥5 cm tumor invasion depth T3-T4，advanced TNM stageⅢ-Ⅳ，lymphatic metastasis，vascular invasion and nerve invasion（P<0.05）. The levels of CD4⁺T，CD8⁺T，CD158a，CD94，NKG2D，NKp30，NKp46，IL-2 and TNF-α were lower（P<0.05）. Compared with good prognosis group after 6 months of chemotherapy，the FZD6 mRNA expression in poor prognosis group was increased（P<0.05）. There was no statistical significance in the relative expression signifioance levels of FZD6 mRNA between the 2 groups before chemstherapy and 1 and 3 months after chemoterapy （P>0.05）. FZD6 mRNA relative expression level was a risk factor for poor prognosis in CRC patients（P<0.05），and tumor invasion depth，TNM stage，lymphatic metastasis，vascular invasion and nerve invasion did not affect the relationship（P>0.05）. FZD6 mRNA was negatively correlated with CD4⁺T，CD8⁺T，CD158a，CD94，NKG2D，NKp30，NKp46，IL-2 and TNF-α（P<0.05）. The area under curve（AUC） of FZD6 mRNA in judging the poor prognosis of CRC patients was 0.927，and the risk of poor prognosis in CRC patients was increased when FZD6 mRNA was >3.09. The 1-year survival rate of patients with low FZD6 mRNA expression（61.43%） was higher than that of patients with high FZD6 mRNA expression（28.33%）（Long-rank χ²=8.565，P<0.05）. Conclusions FZD6 mRNA expression during postoperative chemotherapy in CRC patients is an independent risk factor for poor prognosis，and it is negatively correlated with immune factor levels and positively correlated with the risk of poor prognosis.

Objective To investigate the prognostic role of transmembrane protein 205（TMEM205） in patients with colorectal cancer（CRC）. Methods The expression level of CRC tissue TMEM205 was analyzed in the Cancer Genome Atlas（TCGA） database in relation to the prognosis. Serum samples from 20 CRC patients at Yangpu Hospital of Tongji University School of Medicine from September 2022 to October 2023 were collected，and the research subjects were classified into recurrence group（10 cases） and non-recurrence group（10 cases） according to 1-year prognosis. Totally，5 CRC cell lines（HCT116，SW480，Lovo，RKO，HT29） and normal intestinal epithelial cell line NCM460 were selected. 5-Fluorouracil（5-FU）-resistant cell lines（HCT116/5-FU，SW480/5-FU） and oxaliplatin（OXA）-resistant cell lines（HCT116/OXA，SW480/OXA） were established. The drug-resistant cell lines were classified into knockdown group（transfected with TMEM205-targeting siRNA） and negative control group（transfected with siNC） according to different transfected siRNA. CCK-8 assay，cell colony formation assay，western blotting and real-time fluorescent quantitative polymerase chain reaction（qRT-PCR） were performed to determine the cell proliferation activity，chemotherapeutic drug sensitivity and the expression levels of epithelial-mesenchymal phenotype and cancer stemness markers in cell lines，knockdown group and negative control group. Exosomes were extracted from the culture media of parental HCT116 cells and drug-resistant cell lines，as well as the serum of CRC patients，and the expression level of TMEM205 was determined. Results Based on the analysis of the TCGA database，the overall survival of patients in low TMEM205 expression group was better than that in high TMEM205 expression group [hazard ratio（HR）=1.72，95% confidence interval（CI）1.107-2.659，P=0.016 1]. In CRC tissues，the expression of TMEM205，TNM pathological stage and serum carcinoembryonic antigen（CEA） level were related to poor prognosis in CRC patients with the score span of TMEM205 expression being superior to that of serum CEA. The TMEM205 relative mRNA and protein expression levels in 5 CRC cell lines were higher than those in NCM460 cell lines（P<0.01）. The TMEM205 relative mRNA and protein expression levels in drug-resistant isolates were higher than those in parental cells. Compared with negative control group，the knockdown group showed increased sensitivity to 5-FU and OXA（P<0.001），decreased half-maximal inhibitory concentration （IC₅₀）（P<0.001），and reduced cell colony formation ability（P<0.001）. The expression levels of epithelial phenotype-related markers [E-cadherin（E-Cad），beta-catenin and gamma-catenin] were enhanced（P<0.01），while the expression levels of mesenchymal phenotype-related markers [Vimentin，alpha-smooth muscle actin（α-SMA） and N-cadherin] were reduced（P<0.01）. The expression levels of tumor stemness markers [CD44，octamer-binding transcription factor 4（OCT4），Nanog homebox protein（Nanog） and sex-determining region Y-box protein 2（SOX2）] were decreased（P<0.01）. Conclusions In colorectal cancer cells，high expression of TMEM205 can maintain the drug-resistant phenotype to 5-FU and OXA through epithelial-mesenchymal transition and tumor stemness. TMEM205 may serve as a high-risk prognostic factor for CRC. Serum exosomal TMEM205 shows potential as a biomarker for predicting CRC recurrence.

Objective To investigate the role of combined determination of syndecan-2（SDC2） methylation in fecal shed cells，fecal m3 gene and serum tumor markers [carcinoembryonic antigen（CEA），carbohydrate antigen（CA） 125，CA19-9] in the early screening of colorectal cancer（CRC）. Methods Totally，60 CRC patients（CRC group），40 patients with colorectal adenoma（adenoma group） and 40 controls without abnormalities，polyps or chronic inflammation found during colonoscopy（control group） were enrolled from January 2021 to December 2023 at the Electric Power Teaching Hospital of Capital Medical University. The methylation level of SDC2 gene and the expression level of m3 gene in fecal shed cells were determined by real-time fluorescence quantitative polymerase chain reaction（PCR），and the levels of serum CEA，CA125 and CA19-9 were determined. Logistic regression analysis was used to evaluate the influencing factors of CRC occurrence. Receiver operating characteristic（ROC） curve was used to assess the efficacy of SDC2 methylation，m3 gene，CEA，CA125，CA19-9 single determinations and combined determination in the early screening of CRC. Results The positive determination rates of SDC2 methylation and the expression levels of m3 gene were decreased successively in CRC group，adenoma group and control group（P<0.001）. Elder，m3 gene expression and positive SDC2 methylation were independent risk factors for CRC occurrence（P<0.05）. The areas under curves（AUC） of SDC2 methylation，m3 gene，CEA，CA125 and CA19-9 single determinations for diagnosing CRC were 0.888，0.867，0.719，0.713 and 0.748，respectively. The AUC of combined determination of SDC2 methylation and m3 gene and combined determination of CEA，CA125 and CA19-9 were 0.958 and 0.778，respectively，and the AUC for diagnosing adenoma and stage Ⅰ/Ⅱ CRC were 0.835 and 0.672，respectively. Conclusions The determinations of fecal SDC2 methylation and m3 gene are rapid，simple and non-invasive，and they are potential for CRC screening and diagnosis，especially their combined determination.

Objective To analyze the role of red blood cell distribution width-to-platelet count ratio（RPR） in predicting the short-term prognosis of patients with acute respiratory distress syndrome（ARDS）. Methods The clinical data of ARDS patients in the intensive care unit（ICU） were extracted from the MIMIC-Ⅳ database. The patients were classified into survival group and death group based on their 28 d prognosis. The differences in RPR between the 2 groups were compared. ARDS patients were further classified into high RPR group（RPR≥6.76%） and low RPR group（RPR<6.76%） according to RPR optimal cut-off values. Receiver operating characteristic（ROC） curve was used to evaluate the efficacy of RPR and related disease scores in predicting 28 d mortality in ARDS patients. The differences in prognosis between high RPR group and low RPR group were analyzed through survival curves. Cox risk regression model was used to analyze the influencing factors of 28 d mortality in ARDS patients. Subgroup analysis was conducted based on gender，age and related comorbidities to evaluate the influencing factors related to 28 d mortality in patients with RPR and ARDS. Results The RPR of death group was higher than that of survival group（P<0.001）. Elevated RPR was an independent predictor of the 28 d prognosis in patients with ARDS [hazard ratio （HR）=4.05，P<0.001]，and the area under curve（AUC） for predicting the 28 d prognosis of ARDS patients was 0.776. The 28 d survival rate in high RPR group was lower than that in low RPR group（P<0.05）. The results of subgroup analysis indicated that the correlation between RPR and the 28 d prognosis of ARDS patients had no interaction with gender，age and comorbidities（P_interaction>0.05）. Conclusions Elevated RPR level can be used to predict the 28 d prognosis of patients with ARDS.

Objective To establish a national standard reference material of aldosterone in frozen human serum for the transfer of measurement values and the evaluation of accuracy in aldosterone determination. Methods Clinical serum samples with clear appearance，no obvious jaundice，hemolysis or lipemia，and negative results for 4 infectious disease determinations were collected. After multi-level filtration and sterilization，the samples were classified into high- and low- level candidate reference materials and stored at -70 ℃ or below. The homogeneity，stability and intercommunity of the candidate reference materials were evaluated. Totally，5 laboratories were selected to jointly assign values using the reference method（isotope dilution liquid chromatography-tandem mass spectrometry）. Results The results of homogeneity test showed that the F values of the high- and low- level candidate reference materials were 1.355 3 and 1.473 3，respectively，both <F_0.05（1.511 7）. The results of stability test showed that the candidate reference materials were stable for 5 h at room temperature，20 d at 2-8 ℃，and at least 30 d at -20 ℃. The assigned values of the high- and low- level candidate reference materials were（0.239±0.018）nmol·L^-1（k=2） and（0.845±0.052）nmol·L^-1（k=2），or（86.22±6.31）pg·mL^-1（k=2） and（304.74±18.80）pg·mL^-1（k=2），respectively. The intercommunity of the 2 levels of candidate reference materials was good in 5 mainstream routine determination systems. Conclusions The established aldosterone candidate reference materials are homogeneous and stable and have good intercommunity，with accurate and reliable assigned values，and can be used as national standard reference materials. The establishment of this national standard reference material is of significance for promoting the standardization of aldosterone determination results.

Objective To analyze the differences in gut microbiota（GM） metabolomics and their correlations with schizophrenia（SZ），and to provide a reference for early diagnosis and targeted intervention. Methods Fecal and blood samples were collected from 6 SZ patients（SZ group） and 6 healthy subjects（healthy control group） at Hulunbuir Third People's Hospital in 2023. Fecal samples were used for metagenomic sequencing（mNGS），and blood samples were used for metabolomics analysis by liquid chromatography-mass spectrometry. Random forest machine learning method was used to analyze the characteristics of the microbiota. The different species in the 2 groups were analyzed，and based on the significantly defferent species an early diagnosis model for SZ was consructed. Receiver operating characteristic（ROC） curve was used to evaluate the efficiency for diagnosing SZ. Results The mNGS results showed that there was statistical significance in 18 biomarkers such as Ruminococcus，Phascolarctobacterium，Lachnospira，Megasphaera and Megamonas between the 2 groups（P<0.05）. The metabolism pathways of glycine，serine and threonine were enriched in SZ group（P<0.05），and the 5-hydroxytryptamine receptor agonist/antagonist pathway was enriched（P<0.05）. The fatty acid biosynthesis pathway and steroid biosynthesis pathway were enriched in healthy control group（P<0.05）. The areas under curves（AUC） of Lachnospira，Phascolarctobacterium and Megamonas for diagnosing SZ were 1.000，0.090 and 0.909，respectively. Conclusions For SZ patients，GM，the pathways of 5-hydroxytryptamine receptor agonist/antagonist，fatty acid biosynthesis and steroid biosynthesis pathway have changes，which are related to SZ to some extent.

Objective To investigate the metabolic changes of atopic dermatitis（AD）in children using non-targeted metabolomics technology. Methods A total of 37 children with AD（AD group）and 17 healthy children （control group）were enrolled from Zhuzhou Central Hospital from January 1，2023 to June 30，2023. The metabolites in the serum were determined，and the differentially expressed metabolites were screened. Metabolic pathways were analyzed using the Kyoto Encyclopedia of Genes and Genomes（KEGG）and the Human Metabolome Database（HMDB），and potential biomarkers in the differentially expressed metabolites for the diagnosis of AD were evaluated by receiver operating characteristic（ROC）curve. Results Totally，87 metabolites in AD patients were upregulated（the top 5 were or nithine，glycylproline，gallic acid，hypoxanthine and homocystine），and 46 metabolites were downregulated [the top 5 were D-mannose，（S）-methylmalonyl semialdehyde，（2R_3S）-2_3-malic dimethyl ester，（S）-abscisic acid and 2-oxopentanoic acid]. The involved metabolic pathways included arginine and proline metabolism，D-amino acid metabolism，glycine，serine，threonine metabolism，protein digestion and absorption，arginine biosynthesis and central carbon metabolism in cancer. The areas under curves （AUC） of ornithine，hypoxanthine，homocysteine，D-mannose，（2R_3S）-2_3-malic dimethyl ester，glycylproline，gallic acid，（S）-methylmalonyl semialdehyde，（S）-abscisic acid and 2-oxopentanoic acid were 1.000，1.000，1.000，1.000，1.000，0.950，0.960，0.990，0.940 and 0.940，respectively. Conclusions The metabolic pathways involved in AD patients include amino acid metabolism，protein digestion and absorption and cancer central carbon metabolism，which may be related to the pathogenesis of childhood AD.

Objective To investigate the relationship between serum tumor necrosis factor-alpha（TNF-α），high-sensitivity C-reactive protein（hs-CRP）and interleukin-22（IL-22）and the disease activity and prognosis of pediatric Crohn's disease（CD）. Methods Totally，63 children with CD（CD group）and 63 healthy children（healthy control group） were enrolled from January 2017 to June 2022 at the Children's Hospital of Zhengzhou University. The levels of serum TNF-α，hs-CRP and IL-22 were determined. All the children were classified into non-active group（26 cases）and active group（37 cases）based on the pediatric Crohn's disease activity index（PCDAI）score. All the children were followed up for 1 year，and they were classified into poor prognosis group（24 cases）and good prognosis group（39 cases）based on the prognosis. Pearson correlation analysis was used to evaluate the correlation between the levels of serum TNF-α，hs-CRP and IL-22 and the PCDAI score in children with CD. Receiver operating characteristic（ROC）curve was used to evaluate the efficacy of serum TNF-α，hs-CRP and IL-22 in predicting poor prognosis in children with CD. Results The levels of serum TNF-α，hs-CRP and IL-22 in CD group were higher than those in healthy control group（P<0.05）. The PCDAI score and the levels of serum TNF-α，hs-CRP and IL-22 in active group were higher than those in non-active group（P<0.05）. The PCDAI score in children with CD was positively correlated with the levels of serum TNF-α，hs-CRP and IL-22（r values were 0.595，0.656 and 0.643，respectively，P<0.001）. The levels of serum TNF-α，hs-CRP and IL-22 in poor prognosis group were higher than those in good prognosis group （P<0.001）. Elevated levels of serum TNF-α，hs-CRP and IL-22 were risk factors for poor prognosis in children with CD（P<0.05）. The areas under curves（AUC）of serum TNF-α，hs-CRP，IL-22 single and combined determinations in predicting poor prognosis in children with CD were 0.686，0.752，0.682 and 0.848，respectively. Conclusions The levels of serum TNF-α，hs-CRP and IL-22 are related to the disease activity and prognosis of pediatric CD and may be used as the indicators for assessing the disease activity and prognosis of pediatric CD.

Objective To analyze the significantly differential metabolites after central nervous system leukemia/lymphoma（CNSL） infiltration based on metabolomics，establish a diagnostic model for early prediction of CNSL，and conduct preliminary validation. Methods From January 2018 to September 2021，25 patients with hematological malignancies accompanied by CNSL diagnosed by bone marrow puncture and biopsy at the Department of Hematology of the First Affiliated Hospital of Naval Medical University（CNSL group） and 29 non-tumor patients（control group） were enrolled. The brain cerebrospinal fluid samples were collected. The brain cerebrospinal fluid metabolites were determined using ultra-high performance liquid chromatography-mass spectrometry（UPLC-MS），and the significantly differential metabolites in the 2 groups were screened. Logistic regression analysis was used to evaluate the influence factors for CNSL，and a CNSL prediction model was established. Receiver operating characteristic（ROC） curve was used to evaluate the model efficacy. Totally，5 CNSL patients in the Department of Neurology during the same period were enrolled，and the relevant clinical data were collected for verifying the clinical application effect of the model. Results A total of 36 significantly differential metabolites were screened out，involving 32 metabolic pathways. The top 2 influencing pathways were arginine synthesis and glutamine and glutamete matabolism，including 5 key metabolites such as L-arginine，citrulline，L-glutamine，L-glutamate and urea. Citrulline and L-glutamine were independent rislc factors for to CNSL（P<0.05），and a CNSL diagnosing model was established based on these 2 metabolites. The areas under curves（AUC） of the model for diagnosing CNSL was 0.819，with a sensitivity of 72.0% and a specificity of 82.8%. The clinical verfication results showed that the model's prediction results were in good consistency with the actual observation results. Conclusions The CNSL prediction model established based on significantly differential metabolites can be used for the early diagnosis of CNSL.

Nucleic acid determination technology，due to its advantages such as rapidity，sensitivity，specificity and accuracy，has been widely applied in the determination of bacteria，fungi and parasites，and plays a role in the early screening and diagnosis of infectious diseases. The microbial multiplex nucleic acid determination technology has the characteristics of rapidity，high throughput and low sample consumption，allowing for the simultaneous determination of multiple target microorganisms in the same reaction，enabling the differentiation of mixed infections，and covering a wide range of microbial spectra. This review focuses on the multiplex nucleic acid determination technology based on polymerase chain reaction（PCR） and loop-mediated isothermal amplification（LAMP），as well as its application progress in microbial determination and diagnosis of infectious diseases.