Quantitative and structural characteristics of mitochondrial DNA in varicose veins.

OBJECTIVE: We examined quantitative (in terms of mtDNA/nuclear DNA) and structural (in terms of common deletions in the MT-ND4 gene region) characteristics of mitochondrial DNA (mtDNA) in varicose veins (VVs) and venous wall layers by comparing mitochondrial genome parameters, as well as mitochondrial function (in terms of mitochondrial membrane potential (MtMP)), in varicose vein (VV) vs. non-varicose vein (NV) tissue samples. METHODS: We analyzed paired great saphenous vein samples (VV vs. NV segments from each patient left after venous surgery) harvested from patients with VVs. Relative mtDNA level and the proportion of no-deletion mtDNA were determined by a multiplex quantitative PCR (qPCR), confirming the latter with a more sensitive method - droplet digital PCR (ddPCR). Mitochondria's functional state in VVs was assessed using fluorescent (dependent on MtMP) live-staining of mitochondria in venous tissues. RESULTS: Total mtDNA level was lower in VV than in NV samples (predominantly in the t. media layer). ddPCR analysis showed lower proportion of no-deletion mtDNA in VVs. Because of the decrease in relative MtMP in VVs, our results suggest a possible reduction of mitochondrial function in VVs. CONCLUSION: Quantitative and structural changes (copy number and integrity) of mtDNA are plausibly involved in VV pathogenesis. Future clinical studies implementing the mitochondrial targeting may be eventually fostered after auxiliary mechanistic studies.

Highly Sensitive and Reliable Detection of EGFR Exon 19 Deletions by Droplet Digital Polymerase Chain Reaction.

BACKGROUND: Analysis of EGFR mutations is becoming a routine clinical practice but the optimal EGFR mutation testing method is still to be determined. METHODS: We determined the nucleotide sequence of deletions located in exon 19 of the EGFR gene in lung tumor samples of patients residing in different regions of Russia (153 tumor DNA specimens), using Sanger sequencing. We developed a droplet digital polymerase chain reaction assay capable of detecting all common EGFR deletions in exon 19. We also compared the therascreen amplification refractory mutation system assay with a droplet digital polymerase chain reaction assay for the detection of all the deletions in our study. RESULTS: The droplet digital polymerase chain reaction assay demonstrated 100% sensitivity against polymerase chain reaction fragment length analysis and detected all possible types of deletions revealed in our study (22 types). At the same time, the therascreen EGFR RGQ PCR Kit was not able to detect deletions c.2252-2276>A and c.2253-2276 and showed low performance for another long deletion. CONCLUSION: Thus, we can conclude that the extraordinary length of deletions and their atypical locations (shift at the 3'-region compared to known deletions) could be problematic for the therascreen EGFR RGQ PCR Kit and should be taken into account during targeted mutation test development. However, droplet digital polymerase chain reaction is a promising and reliable assay that can be used as a diagnostic tool to genotype formalin-fixed paraffin-embedded cancer samples for EGFR or another clinically relevant somatic mutation.

Cisplatin and gemcitabine first-line chemotherapy followed by maintenance gemcitabine or best supportive care in advanced non-small cell lung cancer: a phase III trial.

PURPOSE: The primary objective of this randomized phase III study was to show significant difference in median time to progression (TTP) in patients with advanced NSCLC treated with single-agent gemcitabine maintenance therapy versus best supportive care following gemcitabine plus cisplatin initial first-line therapy. PATIENTS AND METHODS: Chemonaive patients with stage IIIB/IV NSCLC received gemcitabine 1,250 mg/m(2) (days 1 and 8) plus cisplatin 80 mg/m(2) (day 1) every 21 days. Patients achieving objective response or disease stabilization following initial gemcitabine plus cisplatin therapy were randomized (2:1 fashion) to receive maintenance gemcitabine (1,250 mg/m(2) on days 1 and 8 every 21 days) plus best supportive care (GEM arm), or best supportive care only (BSC arm). RESULTS: Between November 1999 and November 2002, we enrolled 352 patients (median age: 57 years; stage IV disease: 74%; Karnofsky performance status (KPS) >80: 41%). Following initial therapy, 206 patients were randomized and treated with gemcitabine (138) or best supportive care (68). TTP throughout the study period was 6.6 and 5 months for GEM and BSC arms, respectively, while values for the maintenance period were 3.6 and 2.0 months (for p < 0.001 for both). Median overall survival (OS) throughout study was 13.0 months for GEM and 11.0 months for BSC arms (p = 0.195). The toxicity profile was mild, with neutropenia being most common grade 3/4 toxicities. CONCLUSION: Maintenance therapy with gemcitabine, following initial therapy with gemcitabine plus cisplatin, was feasible, and produced significantly longer TTP compared to best supportive care alone. Further studies are warranted to establish the place of maintenance chemotherapy in patients with advanced NSCLC.