The drift kinetic equation is solved for investigation of the plasma response to electromagnetic geodesic acoustic modes. The plasma flow within magnetic surfaces is considered. A perpendicular magnetic perturbation with poloidal number m=2 is created due to the m=2 parallel return current.

Purpose: Early detection and intervention can decrease the mortality of breast cancer significantly. Assessments of genetic/ genomic variants in circulating tumor DNA (ctDNA) have generated great enthusiasm for their potential application as clinically actionable biomarkers in the management of earlystage breast cancer.Experimental Design: In this study, 861 serial plasma and matched tissue specimens from 102 patients with early-stage breast cancer who need chemotherapy and 50 individuals with benign breast tumors were deeply sequenced via nextgeneration sequencing (NGS) techniques using large gene panels.Results: Cancer tissues in this cohort of patients showed profound intratumor heterogeneities (ITHGs) that were properly reflected by ctDNA testing. Integrating the ctDNA detection rate of 74.2% in this cohort with the corresponding predictive results based on Breast Imaging Reporting and Data System classification (BI-RADS) could increase the positive predictive value up to 92% and potentially dramatically reduce surgical overtreatment. Patients with positive ctDNA after surgery showed a higher percentage of lymph node metastasis, indicating potential recurrence and remote metastasis. The ctDNA-positive rates were significantly decreased after chemotherapy in basal-like and Her2 þ tumor subtypes, but were persistent despite chemotherapy in luminal type. The tumor mutation burden in blood (bTMB) assessed on the basis of ctDNA testing was positively correlated with the TMB in tumor tissues (tTMB), providing a candidate biomarker warranting further study of its potentials used for precise immunotherapy in cancer.Conclusions: These data showed that ctDNA evaluation is a feasible, sensitive, and specific biomarker for diagnosis and differential diagnosis of patients with early-stage breast cancer who need chemotherapy.

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