Удаление метастазов при метастатическом раке толстой кишки с мутацией в гене BRAF — результаты много‑ центрового ретроспективного исследования

Introduction: local treatment of metastases is an integral part of colon cancer treatment. However, there is not enough data on the efficacy of surgical resection of metastases in patients with a BRAF gene mutation to recom‑mend this approach in routine practice. We initiated a retrospective multicenter study to assess the incidence of BRAF gene mutations in patients with metastatic colon cancer and to study the efficacy of metastasectomy in this group of patients.Materials and methods: we selected all patients who underwent surgical resection of metastases in various sites from the database of patients with BRAF gene mutations created as a result of a multicenter retrospective study with participation of 7 clinics in the Russian Federation. All 57 patients with RAS gene mutations and 43 patients with wild‑type RAS and BRAF genes who also underwent surgical resection of metastases at any stage of treatment were selected from the register of the Chemotherapy Department No. 2 of the NMRC of Oncology named after N. N. Blokhin for comparative analysis. Disease‑free survival and overall survival were used as primary efficacy criteria.Results: we found 26 patients with BRAF gene mutations who underwent surgical resection of metastases. When comparing disease‑free survival, the worst median was achieved in the group of patients with BRAF gene mutations: 7 months versus 14 months in patients with RAS gene mutations (HR 0.4, 94 % CI 0.23–0.7, P = 0.006); median disease‑free survival was not achieved in the wild‑type RAS and BRAF group (HR 0.2, 95 % CI 0.11–0.45, P <0.001).The median overall survival in the BRAF gene mutation group was 26 months versus 38 months in the RAS gene mutations group (HR 0.8, 95 % CI 0.33–1.98, P = 0.6) and 49 months in the wtRAS/wtBRAF group (RR 0.46, 95 % CI 0.17–1.24, P = 0.1). Resection of recurrent tumors in patients with metastases in retroperitoneal lymph nodes was associated with extremely low disease‑free survival (2 months); at the same time, disease‑free survival was 7 months after resection of isolated metastases in the liver and 8 months for metastases in the peritoneum.Conclusion: prognosis of patients with a BRAF gene mutation after surgical resection of metastases is worse than in patients with a different mutation phenotype. Nevertheless, literature data, as well as the results of our study, confirm the possibility of performing metastasectomy with careful selection of patients.Цель: Локальные методы лечения метастазов являются неотъемлемой частью терапии больных раком толстой кишки. Однако данных по эффективности хирургического удаления метастазов при мутации в гене BRAF недостаточно, чтобы рекомендовать данный подход в рутинной практике. Нами инициировано ретроспективное многоцентровое исследование по оценки встречаемости мутаций в гене BRAF при метастатическом раке толстой кишки, в рамках которого изучена эффективность метастазэктомии в этой группе пациентов.Материалы и методы: Из базы данных пациентов с мутацией в гене BRAF, созданной в результате многоцентрового ретроспективного исследования с участием 7 клиник Российской Федерации, были отобраны все пациенты, которым проводилось хирургическое удаление метастазов различной локализации. С целью сравнительного анализа из регистра отделения химиотерапии № 2 НМИЦ онкологии им. Н. Н. Блохина были отобраны все 57 пациентов с мутацией в генах RAS и 43 пациента с диким типом генов RAS и BRAF, которым также проводилось хирургическое удаление метастазов на любом из этапов лечения. В качестве основных критериев эффективности рассматривались выживаемость без признаков болезни и общая выживаемость.Результаты: Было найдено 26 больных с мутацией в гене BRAF, которым выполнялось хирургическое удаление метастазов. При сравнении выживаемости без признаков болезни наихудший показатель медианы был достигнут в группе пациентов с мутацией в гене BRAF — 7 месяцев против 14 месяцев при мутации в генах RAS (ОР 0,4, 94% ДИ 0,23–0,7, р=0,006); медиана выживаемости без признаков болезни в группе с диким типом генов RAS и BRAF не была достигнута (ОР 0,2, 95 % ДИ 0,11–0,45, р<0,001). Медиана общей выживаемости в группе с мутацией в гене BRAF составила 26 месяцев против 38 месяцев в группе с мутацией в генах RAS (ОР 0,8, 95% ДИ 0,33–1,98, р=0,6) и 49 месяцев в группе wtRAS/wtBRAF (ОР 0,46, 95% ДИ 0,17–1,24, р=0,1). Удаление рецидивных опухолей и при поражении забрюшинных лимфоузлов метастазами было ассоциировано с крайне низкой выживаемостью без признаков болезни (2 месяца), тогда как при удалении изолированных метастазов в печени она составила 7 месяцев, в брюшине — 8 месяцев.Выводы: Прогноз больных с мутацией в гене BRAF после хирургического удаления метастазов хуже в сравнении с пациентами с другим мутационным фенотипом. Тем не менее, данные литературы, а также результаты нашего исследования подтверждают возможность выполнения метастазэктомии при тщательным отборе пациентов

An alternative role of FoF1-ATP synthase in Escherichia coli: synthesis of thiamine triphosphate

In E. coli, thiamine triphosphate (ThTP), a putative signaling molecule, transiently accumulates in response to amino acid starvation. This accumulation requires the presence of an energy substrate yielding pyruvate. Here we show that in intact bacteria ThTP is synthesized from free thiamine diphosphate (ThDP) and Pi, the reaction being energized by the proton-motive force (Dp) generated by the respiratory chain. ThTP production is suppressed in strains carrying mutations in F1 or a deletion of the atp operon. Transformation with a plasmid encoding the whole atp operon fully restored ThTP production, highlighting the requirement for FoF1-ATP synthase in ThTP synthesis. Our results show that, under specific conditions of nutritional downshift, FoF1-ATP synthase catalyzes the synthesis of ThTP, rather than ATP, through a highly regulated process requiring pyruvate oxidation. Moreover, this chemiosmotic mechanism for ThTP production is conserved from E. coli to mammalian brain mitochondria

Metabolism of Thiamine Triphosphate in Rat Brain: Correlation with Chloride Permeability

Our results show that a net synthesis of thiamine triphosphate (TTP) can be demonstrated in vitro using rat brain extracts. The total homogenate was preincubated with thiamine or its diphosphate derivative (TDP), centrifuged, and washed twice. With TDP (1 mM) as substrate, a 10-fold increase in TTP content was observed in this fraction (nuclear fraction, membrane vesicles). A smaller, but significant, increase was observed in the P2 fraction (mitochondrial/synaptosomal fraction). In view of the low TTP content of our fractions, it was carefully assessed that authentic TTP was being formed. Incorporation of radioactivity from [beta-32P]TDP and [gamma-32P]ATP in TTP suggests that these two compounds are its precursors. Furthermore, TTP synthesis was inhibited by ADP and relatively low concentrations of Zn2+. These results suggest that TTP synthesis is catalyzed by an ATP:TDP transphosphorylase rather than by the cytoplasmic adenylate kinase that may be present in the vesicles. After osmotic lysis of the vesicles at alkaline pH, TTP was recovered in protein-bound form. Concomitantly, a soluble thiamine triphosphatase, with alkaline pH optimum, was also released from the vesicles. No net synthesis could be obtained in the cytosolic fraction or in detergent-solubilized systems. Like TTP synthesis, chloride permeability of the vesicles was increased when the homogenate had been incubated with thiamine and particularly with TDP. Our results suggest a regulatory role of TTP on chloride permeability, but the target remains to be characterized

Calibration and precision of serum creatinine and plasma cystatin C measurement: impact on the estimation of glomerular filtration rate

Serum creatinine (SCr) is the main variable for estimating glomerular filtration rate (GFR). Due to interassay differences, the prevalence of chronic kidney disease (CKD) varies according to the assay used, and calibration standardization is necessary. For SCr, isotope dilution mass spectrometry (IDMS) is the gold standard. Systematic differences are observed between Jaffe and enzymatic methods. Manufacturers subtract 0.30 mg/dl from Jaffe results to match enzymatic results (‘compensated Jaffe method’). The analytical performance of enzymatic methods is superior to that of Jaffe methods. In the original Modification of Diet in Renal Disease (MDRD) equation, SCr was measured by a Jaffe Beckman assay, which was later recalibrated. A limitation of this equation was an underestimation of GFR in the high range. The Chronic Kidney Disease Epidemiology (CKD-EPI) consortium proposed an equation using calibrated and IDMS traceable SCr. The gain in performance was due to improving the bias whereas the precision was comparable. The CKD-EPI equation performs better at high GFR levels (GFR[60 ml/ min/1.73 m2). Analytical limitations have led to the recommendation to give a grade ([60 ml/min/1.73 m2) rather than an absolute value with the MDRD equation. By using both enzymatic and calibrated methods, this cutoff-grade could be increased to 90 ml/min/1.73 m2 (with MDRD) and 120 ml/min/1.73 m2 (with CKD-EPI). The superiority of the CKD-EPI equation over MDRD is analytical, but the precision gain is limited. IDMS traceable enzymatic methods have been used in the development of the Lund– Malmo¨ (in CKD populations) and Berlin Initiative Study equations (in the elderly). The analytical errors for cystatin C are grossly comparable to issues found with SCr. Standardization is available since 2011. A reference method for cystatin C is still lacking. Equations based on standardized cystatin C or cystatin C and creatinine have been proposed. The better performance of these equations (especially the combined CKD-EPI equation) has been demonstrated

The applicability of eGFR equations to different populations

The Cockcroft–Gault equation for estimating glomerular filtration rate has been learnt by every generation of medical students over the decades. Since the publication of the Modification of Diet in Renal Disease (MDRD) study equation in 1999, however, the supremacy of the Cockcroft–Gault equation has been relentlessly disputed. More recently, the Chronic Kidney Disease Epidemiology (CKD-EPI) consortium has proposed a group of novel equations for estimating glomerular filtration rate (GFR). The MDRD and CKD-EPI equations were developed following a rigorous process, are expressed in a way in which they can be used with standardized biomarkers of GFR (serum creatinine and/or serum cystatin C) and have been evaluated in different populations of patients. Today, the MDRD Study equation and the CKD-EPI equation based on serum creatinine level have supplanted the Cockcroft–Gault equation. In many regards, these equations are superior to the Cockcroft–Gault equation and are now specifically recommended by international guidelines. With their generalized use, however, it has become apparent that those equations are not infallible and that they fail to provide an accurate estimate of GFR in certain situations frequently encountered in clinical practice. After describing the processes that led to the development of the new GFR-estimating equations, this Review discusses the clinical situations in which the applicability of these equations is questioned