Potential value of detection of minimal residual disease in colorectal cancer following radical resection

Although there has been significant advancement in the identification and management of colorectal cancer(CRC)in recent years,there is still room for improvement in the current standard treatment regimen.One area of concern is the lack of reliable tumor markers to predict treatment efficacy and guide tailored care.Due to its dynamic,effective,and non-invasive benefits over tissue biopsy,the detection of minimal or molecular residual lesions(MRD)based on circulating tumor DNA(ctDNA)is beneficial to the clinical development of drugs for patients with CRC after radical treatment,as well as for continuous monitoring of tumor recurrence and malignancy molecular gene evolution.The detection of ctDNA can currently be used to guide individual postoperative auxiliary treatment decisions(upgrade or downgrade treatment)in CRC,stratify the risk of clinical recurrence more precisely,and predict the risk of recurrence in advance of imaging examination,according to a large number of observational or prospective clinical studies.With increasing clarity comes the possibility of selecting a regimen of treatment based on postoperative ctDNA,which also improves the accuracy of clinical recurrence risk assessment for CRC.Therefore,it is anticipated that the identification of ctDNA would alter the current framework for dealing with CRC and lead to individualized,stratified precision therapy;however,additional confirmation will require subsequent high-quality,prospective,large-scale randomized controlled studies.This article will provide an overview of the definition and clinical significance of MRD,the primary indications and technological challenges for MRD detection,along with the advancement in clinical research about ctDNA detection following radical resection of the CRC.

Donor-Derived CD19-Targeted T Cell Infusion Eliminates B Cell Acute Lymphoblastic Leukemia Minimal Residual Disease with No Response to Donor Lymphocytes after Allogeneic Hematopoietic Stem Cell Transplantation

Leukemia relapse is still the leading cause of treatment failure after allogeneic hematopoietic stem cell transplantation (allo-HSCT) for B cell acute lymphoblastic leukemia (B-ALL). Relapsed patients with BALL after allo-HSCT have a very short median survival. Minimal residual disease (MRD) is predictive of forthcoming hematological relapse after hematopoietic stem cell transplantation (HSCT);furthermore, eliminating MRD effectively prevents relapse. Donor lymphoblastic infusion (DLI) is the main established approach to treat B-ALL with MRD after allo-HSCT. However, about one-third of patients with MRD are non-responsive to DLI and their prognosis worsens. Although donor-derived cluster of differentiation (CD)19-directed chimeric antigen receptor-modified (CAR) T cells (CART19s) can potentially cure leukemia, the efficiency and safety of infusions with these cells have not yet been investigated in patients with MRD after HSCT. Between September 2014 and February 2018, six patients each received one or more infusions of CART19s from HSCT donors. Five (83.33%) achieved MRD-negative remission, and one case was not responsive to the administration of CAR T cells. Three of the six patients are currently alive without leukemia. No patient developed acute graft-versus-host disease (aGVHD), and no patient died of cytokine release syndrome. Donor-derived CAR T cell infusions seem to be an effective and safe intervention for patients with MRD in B-ALL after allo-HSCT and for those who were not responsive to DLI.

Prognostic relevance of minimal residual disease in colorectal cancer

Presence of occult minimal residual disease in patients with colorectal cancer(CRC)has a strong prognostic impact on survival.Minimal residual disease plays a major role in disease relapse and formation of metastases in CRC.Analysis of circulating tumor cells(CTC)in the blood is increasingly used in clinical practice for disease monitoring of CRC patients.In this review article the role of CTC,disseminated tumor cells(DTC)in the bone marrow and micrometastases and isolated tumor cells(ITC)in the lymph nodes will be discussed,including literature published until September 2013.Occult disease is a strong prognostic marker for patient survival in CRC and defined by the presence of CTC in the blood,DTC in the bone marrow and/or micrometastases and ITC in the lymph nodes.Minimal residual disease could be used in the future to identify patient groups at risk,who might benefit from individualized treatment options.

A comparison of flow cytometry detection of minimal residual disease and chimerism kinetics in chronic lymphocytic leukemia patients after allogeneic hematopoietic stem cell transplantation

Determination of minimal residual disease (MRD) remains crucial for the follow-up after therapy in chronic lymphocytic leukemia (CLL) patients. Chimerism was assessed by short tandem repeat (STR)-PCR and single nucleotide polymorphisms (SNP)-PCR, and MRD by a multicolor flow cytometric approach in 12 consecutive patients with CLL after they received allogeneic stem cell transplantation (SCT). Overall, 11 patients achieved MRD flow negativity [10 had full donor chimerism (FDC) and one had mixed chimerism (MC)]. Only one patient remained with MRD flow positivity and displayed MC. Fifty-six samples were concomitantly studied by both chimerism and MRD flow. A significant correlation was observed between MRD flow data and chimerism in both PB and BM by using a mixed effect linear regression (p < 0.001). Flow cytometry approach of MRD can be easily combined with chimerism during the follow-up post-allogeneic SCT. Both techniques appeared complementary for guiding post-transplant immunomodulation.

Improvement of the minimal residual method for solving nonsymmetric linear systems

In this paper, the minimal residual （MRES） method for solving nonsymmetric equation systems was improved, the recurrence relation was deduced between the approximate solutions of the linear equation system Ax = b, and a more effective method was presented, which can reduce the operational count and the storage.

Coexisting opportunities and challenges:In which scenarios can minimal/measurable residual disease play a role in advanced non-small cell lung cancer?

Curative therapy was not previously available for patients with advanced non-small cell lung cancer(NSCLC);thus,the concept of minimal/measurable(or molecular)residual disease(MRD)was not applicable to these patients.However,advances in targeted and immunotherapy have revolutionized the treatment landscape for patients with advanced NSCLC,with emerging evidence of long-term survival and even the hope of complete remission(CR)by imaging examination.The latest research shows that patients with oligometastatic lung cancer can benefit from local treatment.After removing the lesions,the choice of follow-up therapy and monitoring of the lesions could remain uncertain.MRD plays a role in identifying early-stage NSCLC patients with high risks of recurrence and determining adjuvant therapy after radical treatment.In recent years,evidence has been accumulating regarding the use of circulating cell-free tumor DNA(ctDNA)to assess MRD in solid tumors.This study discussed the possible applications of ctDNA-based MRD monitoring in advanced NSCLC and described the current challenges and unresolved problems in the application of MRD in advanced NSCLC.

High-precision downward continuation of potential fi elds algorithm utilizing adaptive damping coeffi cient of generalized minimal residuals

The downward continuation of potential fields is a process of calculating their values in a lower plane based on those of a certain plane.This technology is not only a data processing method for resource exploration but also plays an extremely important role in military applications.However,the downward continuation of potential fields is a typical linear inverse problem that is ill-posed.Generalized minimal residuals(GMRES)is an eff ective solution to ill-posed inverse problems,but it is unstable under the condition wherein the GMRES is directly applied in the calculation process.Moreover,the long-term behavior of its iterative computation is a disordered,divergent result.Therefore,to obtain stable solutions,GMRES is applied to solve the normal equations of the downward continuation of potential fields;it is also used to prequalify for occasional interruptions in the operation process by adding the damping coefficient,thus strengthening the stability conditions of the equations of residual minimization.Finally,the stable downward continuation of the potential fields method is proposed.As indicated by the theoretical data and the measured testing data,the method proposed in this paper has the advantages of high-precision and excellent stability.Furthermore,compared with the Tikhonov iteration method,the proposed method avoids the need to choose regularization parameters.

DETECTION AND ITS CLINICAL VALUE OF MINIMAL RESIDUAL DISEASES IN ACUTE PROMYELOCYTIC LEUKEMIA

Objective: To detect the minimal residual diseases (MRD) in acute promyelocytic leukemia (APL) after complete remission (CR) and to analyze its clinical value in prognosis. Methods: Reverse transcription Polymerase chain reaction (RT/PCR) was used to detect MRD of patients with APL. Results: MRD positive rate in patients with APL was 92.8% (39/42) before treatment and 56.7 (21/37) immediately after the ATRA or chemotherapy-induced CR. Furthermore, MRD positive rate was related to the relapse in APL patients and could be considered as a marker to predict the relapse of patients with APL after CR. The MRD detection could also be applied to direct the consolidation therapy to prevent relapses. Conclusion: RT-PCR is valuable to monitor MRD and can be used as a marker to predict relapses.

CLINICAL SIGNIFICANCE OF THE DETECTION OF MINIMAL RESIDUAL DISEASE IN CHILDHOOD B-ALL BY FLOW CYTOMETRY

Objective To detect the minimal residual disease in children with B-ALL and to evaluate its clinical significance by flow cytometry. Methods 58 childhood B-ALL cases were enrolled into this study and 33 MRD analyses were performed after remission induction therapy.Four-color combinations of fluorochrome labeled monoclonal antibodies against lymphocyte lineage related phenotypes were used to analyze leukemic cells with flow cytometry.The cells from normal bone marrow were used as controls.The combinations of phenotypes that reflect the antigen expression differences between leukemic and normal bone marrow cells on flow cytometry were considered to be the effective phenotype combinations in the first step screening.The effective phenotype combinations were then used to monitor MRD during the disease course after therapy began. Results 58 cases of childhood B-ALL were screened for MRD effective phenotype combinations.The effective phenotype combinations were identified in 89.7% of B-ALL cases in this study.Four-color phenotype combinations were composed of CD10/CD34/CD19 plus another effective marker such as CD38,CD58,CD66c,CD21.The senstitivity of this method was 0.01%,much higher than that of microscopic inspection.In 8 cases,their bone marrow microscopic inspection results showed no remaining leukemic cells;but with flow cytometry,the percentage of leukemic cells were 5.66%,0.36%,1.43%,0.069%,1.55%,2.7%,0.028% and 0.015%,respectively.In risk stratification,all these MRD positive cases were classified into high risk group for relapse and 1 case showed early relapse within 6 months. Conclusion The application of flow cytometry in MRD measurement can significantly improve the sensitivity of detection of remained leukemic cells in childhood B-ALL,and can provide more accurate information on disease progression as well as the efficacy of therapy,thus facilitate future treatment decisions and follow ups.

Liquid biopsy and blood-based minimal residual disease evaluation in multiple myeloma

Novel drug availability has increased the depth of response and revolutionised the outcomes of multiple myeloma patients.Minimal residual disease evaluation is a surrogate for progression-free survival and overall survival and has become widely used not-only in clinical trials but also in daily patient management.Bone marrow aspiration is the gold standard for response evaluation,but due to the patchy nature of myeloma,false negatives are possible.Liquid biopsy and blood-based minimal residual disease evaluation consider circulating plasma cells,mass spectrometry or circulating tumour DNA.This approach is less invasive,can provide a more comprehensive picture of the disease and could become the future of response evaluation in multiple myeloma patients.

Study of Minimal Residual Disease in Adults with B-Lineage Acute Lymphoblastic Leukemia by Flowcytometry

Background: After achieving morphological remission, existence of few number of leukemic cells in the patient’s blood represents the minimal residual disease (MRD) and its monitoring helps in evaluating early treatment response and future relapse. Patients and methods: Eighty seven newly diagnosed (B-ALL) cases were enrolled in the present study in the time period from October 2013 to October 2016. A panel of 4 monoclonal antibodies (CD10FITC, CD19PE, CD34PercP and CD45APC) were defined at diagnosis and after morphological remission for tracing of minimal residual disease (MRD). Results: Eighty seven newly diagnosed B-ALL cases were included in the present study of which 73 (84%) showed positive expression to CD45 in combination with (CD10, CD19 and CD34) at diagnosis, which allow us to use this combination for further assessment of MRD after morphological remission. In our study 65% of patients had negative MRD ( Conclusion: MRD detection by flow cytometry using the combination of CD45 with CD10, CD19 & CD34 is an easy and reliable method. Patients with positive MRD are at higher risk of relapse and have inferior overall survival rates compared to those with MRD-ve. Future studies focusing on treatment intensification for the group of patients with +ve MRD aiming to improve the treatment outcome are warranted.

Brentuximab Vedotin Monotherapy and Combined with Low Dose Donor Lymphocyte Infusion to Control Minimal Residual Disease and Sustain Clinical Remission in a Child with Relapsed Anaplastic Large Cell Lymphoma

Minimal residual disease (MRD) appears to have a strong negative predictive value for disease recurrence in children with anaplastic large cell lymphoma (ALCL). Brentuximab vedotin (BV) can be a therapeutic option for MRD-positive patients to achieve molecular remission and to decrease risk of subsequent relapse. We here report a 4-year-old child with ALCL progression during relapse treatment who received BV as a bridging therapy before haploidentical hematopoietic stem-cell transplantation, and as a maintenance therapy post-transplant alone or combined with simultaneous low dose donor-lymphocyte infusions. MRD monitoring showed a complete molecular response and reflected both BV efficiency and graft-versus-lymphoma effect.

The potential role of minimal/molecular residual disease in colorectal cancer: curative surgery, radiotherapy and beyond

Detection of minimal/molecular residual disease(MRD)based on ctDNA assay develops from hematological malignancies to solid tumors.Generally,there are two mainstream assays in MRD testing technology:tumor-informed and tumor-agnostic.For colorectal cancer(CRC),MRD is used not only to monitor recurrence and predict prognosis,but also to help in clinical decision making and assessment of clinical efficacy in the settings of curative surgery,radiotherapy,chemotherapy and surveillance.Accumulated clinical trials are exploring roles of MRD in early or advanced stages of CRC.Here,we give an overview of how MRD is and will be used in CRC.

Surgery for Residual Inferior Left-to-Right Atrial Shunt

We report the case of three female patients who were scheduled for surgical correction of residual left-to-right shunt after initial repair of sinus venosus atrial septal defect(SV-ASD)during childhood.After excluding the possibility of an hemodynamic intervention,all three patients underwent a successful surgical closure through a right mini sub-axillary approach by using total peripheral cannulation for cardiopulmonary bypass and leaving the inferior vena cava completely un-snared allowing for an optimal visualization of the residual atrial septal communication and avoiding extensive dissection of mediastinal structures.

移植前控制营养状况和移植后微小残留病灶对多发性骨髓瘤患者自体造血干细胞移植预后的影响

目的:探讨多发性骨髓瘤患者自体造血干细胞移植前控制营养状况(CONUT)和移植后微小残留病灶对预后的影响。方法:回顾性分析2011-2020年在本院行自体造血干细胞移植的79例患者的临床资料,根据首次移植前CONUT评分将患者分为Low-CONUT组(0-4分,62例)和High-CONUT组(5-12分,17例),对比分析两组患者的临床特征、造血重建与不良反应、疗效和生存情况,同时对预后进行危险因素分析,并用时间依赖的ROC曲线验证结果。结果:High-CONUT组男性患者比例和初诊时骨髓浆细胞>30%的患者比例均较Low-CONUT组高(均P<0.05),而在造血重建与不良反应(2级以上的非血液学不良反应)方面无显著差异。Low-CONUT组移植前完全缓解率、完全缓解+非常好的部分缓解率都显著高于High-CONUT组(均P<0.05),移植后3个月后者优势仍然保持(P<0.01),但前者已无显著差异(P>0.05)。Low-CONUT组总生存期、无进展生存期均优于High-CONUT组(均P<0.05)。移植前的CONUT评分低(0-4分)、移植后6个月微小残留病阴性是患者总生存期和无进展生存期的有利因素(均P<0.05),初诊时国际骨髓瘤工作组预后危险分层为高危和移植前乳酸脱氢酶>250 U/L仅是无进展生存期的危险因素(均P<0.05)。时间相关的ROC曲线分析提示,CONUT评分和移植后6个月微小残留病灶状态可单独或联合预测1和2年总生存期、无进展生存期,且联合预测效果更好。结论:结合移植前CONUT评分和移植后微小残留病灶状态可以较好地预测多发性骨髓瘤患者的预后。

IgH基因重排在多发性骨髓瘤自体造血干细胞移植后微小残留病监测中的价值

目的:探讨免疫球蛋白重链(IgH)基因重排在多发性骨髓瘤(MM)自体造血干细胞移植(auto-HSCT)后微小残留病监测中的价值。方法:收集2018年-2022年于武汉市第一医院血液内科接受auto-HSCT的26例MM患者的临床资料,通过多重PCR联合毛细管电泳片段分析法检测IgH重排来评价微小残留病(MRD),对疾病的转归进行相关统计学分析。结果:全部26例MM患者中,男性18例,女性8例,中位年龄59(41-70)岁,移植后中位随访时间33(7-52)个月。与骨髓IgH重排阴性组(17例)比较,移植前骨髓IgH重排阳性(9例)患者移植后3个月达到CR和sCR疗效的比例更低(1/9 vs 14/17),移植后缓解持续的时间(DOR)更短(10.78±4.35 vs 15.88±5.22个月),两组DOR差异有统计学意义(P<0.05);与外周血干细胞采集物IgH重排阴性组(21例)比较,外周血干细胞采集物IgH重排阳性(5例)患者移植后3个月达到CR和sCR的比例更低(0/5 vs 15/21),移植后缓解持续的时间(DOR)更短(9.60±4.83 vs 15.19±5.11个月),两组DOR差异有统计学意义(P<0.05)。在随访期内,移植前骨髓IgH重排阳性的患者有5例(5/9)死亡,IgH重排阴性患者均存活;外周血干细胞采集物IgH重排阳性患者有4例(4/5)死亡,IgH重排阴性患者有1例死亡(1/21)。无论是骨髓还是外周血干细胞采集物标本,IgH重排阳性患者移植后生存时间较IgH重排阴性患者更短(P<0.05)。Logistic回归分析结果显示,性别、疾病分期、初诊时骨髓涂片浆细胞比例、干细胞动员方案、移植前疗效评价(≥CR和<CR)、CD34+细胞计数对移植前骨髓及干细胞采集物IgH重排均无影响(P>0.05)。结论:通过检测接受auto-HSCT的MM患者IgH重排,可以进一步评价MRD的深度,对疾病的疗效及预后判断有一定的指导意义。

AML化疗期间不同时间点流式细胞术MRD检测对预后的影响

目的:探讨AML化疗期间不同时间点流式细胞术微小残留病(MRD)检测对预后的影响。方法:回顾性分析2018年3月到2022年3月确诊并规范化疗的130例成人原发AML患者,用流式细胞术检测MRD,Kaplan-Meier曲线进行生存分析,log-rank检验进行差异性分析,Cox比例风险回归模型进行影响患者生存的单因素和多因素分析。竞争风险模型进行影响患者累计复发率(CIR)的分析,Fine-Gray进行差异性分析。结果:130例患者中,CR181例,CR226例,PR 14例,NR 9例。CR1组OS高于CR2、PR、NR组。CR2组OS高于PR组,但与NR组比较无统计学差异;PR组OS与NR组比较无统计学差异。CR1和CR2的107例患者根据流式细胞术检测的MRD分组,第一次诱导化疗后MRD~-和MRD~+组患者的4年预期RFS率分别为65.3%和27.9%,4年预期OS率分别为58.7%和41.4%,4年预计CIR率分别为34.7%和69.7%,2组比较差异均有统计学意义(χ^(2)=6.639,P=0.010;χ^(2)=6.131,P=0.013;χ^(2)=6.637,P=0.010);第二次化疗后MRD~-和MRD~+组患者的4年预期RFS率分别为50.8%和37.9%,4年预期OS率分别为49.2%和44.5%,4年预计CIR率分别为49.2%和59.5%,2组比较差异均无统计学意义(χ^(2)=1.475,P=0.225;χ^(2)=2.432,P=0.119;χ^(2)=1.416,P=0.234);巩固治疗期间MRD~-和MRD~+组患者的4年预期RFS率分别为51.9%和29.6%,4年预期OS率分别为67.5%和24.6%,4年预计CIR率分别为48.1%和70.4%,2组比较差异均有统计学意义(χ^(2)=20.982,P<0.001;χ^(2)=17.794,P<0.001;χ^(2)=19.879,P<0.001);3个时间点MRD均为阴性和任一时间点为阳性患者的4年预期RFS率分别为69.9%和33.3%,4年预期OS率分别为59.1%和44.7%,4年预计CIR率分别为30.1%和65.1%,2组比较差异均有统计学意义(χ^(2)=7.367,P=0.007;χ^(2)=6.042,P=0.014;χ^(2)=7.662,P=0.006)。单因素分析结果显示,染色体高危核型是影响患者RFS和OS的不利因素,诱导化疗2个疗程达CR、第一次诱导化疗后MRD~-和第二次化疗MRD~-是患者RFS和OS的保护因素;巩固治疗期间MRD~-和3个时间点MRD~-是患者RFS、OS和CIR的保护因素。多因素分析结果显示,诱导化疗2个疗程达CR是患者RFS和CIR的保护因素,巩固治疗期间MRD~-是RFS、OS和CIR的保护因素。结论:成人AML患者早期获得CR和MRD~-,特别是巩固治疗期间的MRD~-是预后良好的标志,流式细胞术是AML患者MRD检测最常用的方法。

含逆变型分布式电源的不平衡配电网快速短路电流计算

为实现含逆变型分布式电源的不平衡配电网快速短路电流计算,首先建立计及故障穿越控制的逆变型分布式电源序等效受控电流源模型,通过引入虚拟线路和虚拟节点并结合广义Fortescue变换建立不平衡配电网的系统序导纳矩阵。在此基础上构建含逆变型分布式电源不平衡配电网的序节点电压方程,提出基于序分量的短路电流迭代计算方法。通过引入预条件处理的广义极小残余法可避免求解系统序阻抗矩阵,能够有效提升短路电流迭代计算的计算速度。最后,通过对含逆变型分布式电源的13节点、123节点和多个大型合成系统仿真结果对比,验证了所提方法的正确性和可行性。

基于带参数单步块方法的电力系统暂态稳定性数值计算方法

针对电力系统暂态稳定性的在线实时分析,为达到快速求解电力系统暂态稳定性的目的,提出了一种基于带参数单步块方法的电力系统暂态稳定性数值计算方法。使用带参数的单步块方法计算格式,对连续差分离散的暂态稳定性计算进行微分方程求解,并采用牛顿法整体求解差分后得到的非线性代数方程组。采用广义极小残余方法(GMRES)求解方程经块边界值方法(BVM)离散后的代数方程组,并采用预处理矩阵提高算法的收敛性。通过对IEEE145节点的暂态稳定性计算系统进行仿真测试,并将计算结果与同阶方法进行对比。仿真结果表明,文中方法在计算精度、通用性和数值稳定性上效果明显,取得了较好的结果,可达到快速求解电力系统暂态稳定性的目的。

定期监测微小残留病变对儿童急性淋巴细胞白血病的预后价值

背景微小残留病变(MRD)用于监测和评估儿童急性淋巴细胞白血病(ALL)的治疗反应,并根据MRD水平进行危险度分层。目的探讨ALL患儿化疗期间及结束化疗后定期监测MRD对复发的预后价值。设计回顾性队列研究。方法收集2015年1月至2020年2月华中科技大学同济医学院附属同济医院(我院)接受CCCG-ALL 2015方案化疗的初诊ALL连续病例的临床资料,使用流式细胞术检测MRD。分析定期监测MRD与早期预测复发之间的关系。主要结局指标无复发生存期(RFS)。结果224例患儿纳入本文分析,男134例,女90例,中位年龄4.8岁。①诱导缓解第19天(D19)MRD阳性104例(46.4%),第46天(D46)MRD阳性23例(10.3%)。从诱导缓解后(16周)至结束化疗(125周)MRD均阴性145例。结束化疗后随访期间(152~287周),13例MRD阳性,其中11例(84.6%)复发。②28例患儿复发,中位复发时间33月,14例存活,12例死亡,2例失访;20例骨髓复发,其中2例合并睾丸复发,1例合并中枢神经系统复发(CNSL);8例单纯CNSL。③224例患儿随访时间52(IQR:36.5~69.5)月,5年RFS(84.5±2.8)%。D46 MRD≥0.01%与<0.01%、诱导缓解后至结束化疗期间MRD均阴性与MRD至少1次阳性患儿的5年RFS差异均有统计学意义(P<0.05)。结论D46 MRD≥0.01%及诱导缓解后至结束化疗期间MRD至少1次阳性的患儿预后较差。化疗过程中定期监测MRD十分重要。