The prospect and challenge of liquid biopsy in the diagnosis and treatment of chest malignancy / 中华预防医学杂志

In recent years, the incidence of chest malignant tumors in China has increased year by year, which has seriously threatened the health problems of people. Among them, early screening and intervention of patients with chest malignancies is the key to cancer prevention. Early detection, early diagnosis, and early treatment as the "three early prevention" of clinical practice are conducive to improve the survival rate of tumor patients. As a non-invasive and real-time reflection of tumor status, liquid biopsy has gradually received attention in clinical diagnosis and treatment. Circulating tumor cells (CTCs), circulating tumor DNA (ctDNA) and exosomes as liquid biopsy "Three carriages" are not only widely used in the diagnosis, monitoring and prognostic evaluation of chest malignancies, but also face many unknown challenges. In this article, the application of liquid biopsy in chest malignancies in recent years is elaborated in detail, which provides a reference for the formulation of clinical tumor prevention and diagnosis and treatment strategies.

Analysis of the feasibility and prognostic value of circulating tumor DNA monitoring in detecting gene mutations in patients with diffuse large B-cell lymphoma receiving chimeric antigen receptor T-cell therapy / 中华血液学杂志

Objective: To explore the prognostic value of circulating tumor DNA (ctDNA) testing in patients with refractory/relapsed diffuse large B-cell lymphoma (R/R DLBCL) undergoing chimeric antigen receptor T-cell (CAR-T) therapy, and to guide the prevention and subsequent treatment of CAR-T-cell therapy failure. Methods: In this study, 48 patients with R/R DLBCL who received CAR-T-cell therapy at the First Affiliated Hospital of Zhejiang University School of Medicine between December 2017 and March 2022 were included. Furthermore, ctDNA testing of 187 lymphoma-related gene sets was performed on peripheral blood samples obtained before treatment. The patients were divided into complete remission and noncomplete remission groups. The chi-square test and t-test were used to compare group differences, and the Log-rank test was used to compare the differences in survival. Results: Among the patients who did not achieve complete remission after CAR-T-cell therapy for R/R DLBCL, the top ten genes with the highest mutation frequencies were TP53 (41%), TTN (36%), BCR (27%), KMT2D (27%), IGLL5 (23%), KMT2C (23%), MYD88 (23%), BTG2 (18%), MUC16 (18%), and SGK1 (18%). Kaplan-Meier survival analysis revealed that patients with ctDNA mutation genes >10 had poorer overall survival (OS) rate (1-year OS rate: 0 vs 73.8%, P<0.001) and progression-free survival (PFS) rate (1-year PFS rate: 0 vs 51.8%, P=0.011) compared with patients with ctDNA mutation genes ≤10. Moreover, patients with MUC16 mutation positivity before treatment had better OS (2-year OS rate: 56.8% vs 26.7%, P=0.046), whereas patients with BTG2 mutation positivity had poorer OS (1-year OS rate: 0 vs 72.5%, P=0.005) . Conclusion: ctDNA detection can serve as a tool for evaluating the efficacy of CAR-T-cell therapy in patients with R/R DLBCL. The pretreatment gene mutation burden, mutations in MUC16 and BTG2 have potential prognostic value.

Research progress on circulating tumor DNA as a biomarker for minimal residual disease in solid tumors / 中国当代儿科杂志

Circulating tumor DNA (ctDNA) is emerging as a novel biomarker for tumor evaluation, offering advantages such as high sensitivity and specificity, minimal invasiveness, and absence of radiation. Currently, various techniques including gene sequencing and PCR are employed for ctDNA detection. The utilization of ctDNA for monitoring minimal residual disease (MRD) enables comprehensive assessment of tumor status and early identification of tumor recurrence, achieving a remarkable detection sensitivity of 0.01%. Therefore, ctDNA holds promise as a biomarker for early diagnosis, treatment response monitoring, and prognosis prediction in solid tumors. This article reviews the commonly used methods for detecting ctDNA and their advantages in evaluating tumor MRD and guiding clinical diagnosis and treatment.

18F-FDG PET/CT Metabolic Parameters and Circulating Tumour DNA Mutation Abundance in Diffuse Large B-Cell Lymphoma: Correlation and Survival Analysis / 中国实验血液学杂志

OBJECTIVE@#To investigate the correlation between 18Fluoro-deoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) metabolic parameters and peripheral blood circulating tumour DNA (ctDNA) in patients with diffuse large B-cell lymphoma (DLBCL), and the prognostic value of these two types of parameters in predicting progression-free survival (PFS).@*METHODS@#Clinical, PET/CT and ctDNA data of DLBCL patients who underwent peripheral blood ctDNA testing and corresponding PET/CT scans during the same period were retrospectively analyzed. At the time of ctDNA sampling and PET scan, patients were divided into baseline and relapsed/refractory (R/R) groups according to different disease conditions. CtDNA mutation abundance was expressed as variant allele frequency (VAF), including maximum VAF (maxVAF) and mean VAF (meanVAF). Total metabolic tumour volume (TMTV) and total lesion glycolysis (TLG) were obtained by the 41% maximum normalized uptake value method, and the distance between the two farthest lesions (Dmax) was used to assess the correlation between PET parameters and ctDNA mutation abundance using Spearman correlation analysis. The receiver operating characteristic (ROC) curves were used to obtain the optical cut-off values of those parameters in predicting PFS in the baseline and R/R groups, respectively. Survival curves were outlined using the Kaplan-Meier method and log-rank test was performed to compare survival differences.@*RESULTS@#A total of 67 DLBCL patients ［28 males and 39 females, median age 56.0(46.0, 67.0) years］ were included and divided into baseline group (29 cases) and R/R group (38 cases). Among these PET parameters, baseline TMTV, TLG, and Dmax were significantly correlated with baseline ctDNA mutation abundance, except for maximum standardized uptake value (SUVmax) (maxVAF vs TMTV: r=0.711; maxVAF vs TLG: r=0.709; maxVAF vs Dmax: r=0.672; meanVAF vs TMTV: r=0.682; meanVAF vs TLG: r=0.677; meanVAF vs Dmax: r=0.646). While in all patients, these correlations became weaker significantly. Among R/R patients, only TMTV had a weak correlation with meanVAF (r=0.376). ROC analysis showed that, the specificity of TMTV, TLG and Dmax in predicting PFS was better than mutation abundance, while the sensitivity of ctDNA mutation abundance was better. Except R/R patients, TMTV, TLG, Dmax, and VAF were significantly different at normal/elevated lactate dehydrogenase in baseline group and all patients (all P<0.05). Survival curves indicated that high TMTV (>109.5 cm3), high TLG (>2 141.3), high Dmax (>33.1 cm) and high VAF (maxVAF>7.74%, meanVAF>4.39%) were risk factors for poor PFS in baseline patients, while only high VAF in R/R patients (both maxVAF and meanVAF >0.61%) was a risk factor for PFS.@*CONCLUSION@#PET-derived parameters correlate well with ctDNA mutation abundance, especially in baseline patients. VAF of ctDNA predicts PFS more sensitively than PET metabolic parameters, while PET metabolic tumour burden with better specificity. TMTV, TLG and VAF all have good prognostic value for PFS. PET/CT combined with ctDNA has potential for further studies in prognostic assessment and personalized treatment.

Correlation of circulating tumor DNA EGFR mutation levels with clinical outcomes in patients with advanced lung adenocarcinoma / 中华医学杂志(英文版)

BACKGROUND@#Circulating tumor DNA (ctDNA) is a promising biomarker for non-invasive epidermal growth factor receptor mutations (EGFRm) detection in lung cancer patients, but existing methods have limitations in sensitivity and availability. In this study, we used the ΔCt value (mutant cycle threshold [Ct] value-internal control Ct value) generated during the polymerase chain reaction (PCR) assay to convert super-amplification-refractory mutation system (superARMS) from a qualitative method to a semi-quantitative method named reformed-superARMS (R-superARMS), and evaluated its performance in detecting EGFRm in plasma ctDNA in patients with advanced lung adenocarcinoma.@*METHODS@#A total of 41 pairs of tissues and plasma samples were obtained from lung adenocarcinoma patients who had known EGFRm in tumor tissue and were previously untreated. EGFRm in ctDNA was identified by using superARMS. Through making use of ΔCt value generated during the detection process of superARMS, we indirectly transform this qualitative detection method into a semi-quantitative PCR detection method, named R-superARMS. Both qualitative and quantitative analyses of the data were performed. Kaplan-Meier analysis was performed to estimate the progression-free survival (PFS) and overall survival (OS). Fisher exact test was used for categorical variables.@*RESULTS@#The concordance rate of EGFRm in tumor tissues and matched plasma samples was 68.3% (28/41). At baseline, EGFRm-positive patients were divided into two groups according to the cut-off ΔCt value of EGFRm set at 8.11. A significant difference in the median OS (mOS) between the two groups was observed (EGFRm ΔCt ≤8.11 vs. >8.11: not reached vs. 11.0 months; log-rank P = 0.024). Patients were divided into mutation clearance (MC) group and mutation incomplete clearance (MIC) group according to whether the ΔCt value of EGFRm test turned negative after 1 month of treatment. We found that there was also a significant difference in mOS (not reached vs. 10.4 months; log-rank P = 0.021) between MC group and MIC group. Although there was no significant difference in PFS between the two groups, the two curves were separated and the PFS of MC group tended to be higher than the MIC group (not reached vs. 27.5 months; log-rank P = 0.088). Furthermore, EGFRm-positive patients were divided into two groups according to the cut-off of the changes in ΔCt value of EGFRm after 1 month of treatment, which was set at 4.89. A significant difference in the mOS between the two groups was observed (change value of ΔCt >4.89 vs. ≤4.89: not reached vs. 11.0 months; log-rank P = 0.014).@*CONCLUSIONS@#Detecting EGFRm in ctDNA using R-superARMS can identify patients who are more likely sensitive to targeted therapy, reflect the molecular load of patients, and predict the therapeutic efficacy and clinical outcomes of patients.

Circulating tumor DNA in lung cancer: real-time monitoring of disease evolution and treatment response / 中华医学杂志(英文版)

Lung cancer is one of the leading causes of all cancer-related deaths. Circulating tumor DNA (ctDNA) is released from apoptotic and necrotic tumor cells. Several sensitive techniques have been invented and adapted to quantify ctDNA genomic alterations. Applications of ctDNA in lung cancer include early diagnosis and detection, prognosis prediction, detecting mutations and structural alterations, minimal residual disease, tumor mutational burden, and tumor evolution tracking. Compared to surgical biopsy and radiographic imaging, the advantages of ctDNA are that it is a non-invasive procedure, allows real-time monitoring, and has relatively high sensitivity and specificity. Given the massive research on non-small cell lung cancer, attention should be paid to small cell lung cancer.