Monitoring of the presence of EGFR-mutated DNA during EGFR-targeted therapy may assist in the prediction of treatment outcome.

The aim of our trial was to evaluate the prognostic significance of qualitative ctDNA analysis on different stages of EGFR mutated non-small cell lung cancer (NSCLC) treatment. We included 99 patients amendable for the first line treatment with either gefitinib/erlotinib (n = 87), afatinib (n = 10) or osimertinib (n = 2). Sequential qualitative analysis of ctDNA with cobas® EGFR Mutation Test v2 were performed before first dose, after 2 and 4 months of treatment, and on progression. Our analysis showed clinically significant heterogeneity of EGFR-mutated NSCLC treated with 1st line tyrosine kinase inhibitors (TKIs) in terms of progression-free and overall survival. When treated with conventional approach, i.e. monotherapy with TKIs, the patients falls into three subgroups based on ctDNA analysis before and after 2 months of treatment. Patients without detectable ctDNA at baseline (N = 32) possess the best prognosis on duration of treatment (PFS: 24.07 [16.8-31.3] and OS: 56.2 [21.8-90.7] months). Those who achieve clearance after two months of TKI (N = 42) have indistinguishably good PFS (19.0 [13.7 - 24.2]). Individuals who retain ctDNA after 2 months (N = 25) have the worst prognosis (PFS: 10.3 [7.0 - 13.5], p = 0.000). 9/25 patients did not develop ctDNA clearance at 4 months with no statistical difference in PFS from those without clearance at 2 months. Prognostic heterogeneity of EGFR-mutated NSCLC should be taken into consideration in planning further clinical trials and optimizing the outcome of patients.

[Abnormal tropomyosin function in ATPase cycle in hypertrophic and dilated cardiomyopathies].

Pathogenesis of most myopathies including inherited hypertrophic (HCM) and dilated (DCM) cardiomyopathies is based on modification of structural state of contractile proteins induced by point mutations, such as mutations in alpha-tropomyosin (TM). To understand the mechanism of abnormal function of contractile system of muscle fiber due to Glu180Gly, Asp175 or Glu40Lys, Glu54Lys mutations in alpha-TM associated with HCM or DCM, we specifically labeled alpha-TM by fluorescence probe 5-IAF after Cys-190 and examined the position and mobility of the IAF-TM in the ATP hydrolysis cycle using polarized fluorescence technique. Analysis of the data suggested that the point mutations in alpha-TM associated with hypertrophic or dilated cardiomyopathy caused abnormal changes in the affinity ofTM to actin and in the position of this protein on the thin filaments in the ATPase cycle. Mutations in alpha-TM associated with HCM caused a shift of TM strands to the center of the thin filament and increased a range of tropomyosin motion and affinity of this protein to actin in the ATPase cycle. In contrast, mutations in alpha-TM associated with DCM shifted the protein to the periphery of the thin filament, reduced the amplitude of the TM movement and its affinity for actin. It is proposed that anomalous behavior of TM on the thin filaments in ATPase cycle may provoke the dysfunction of the cardiac muscle in patients with HCM and DCM.