Searches for the light invisible axion-like particle in K+→π+π0aK^{+}\to\pi^{+}\pi^{0}a decay

A high statistics data sample of the $K^{+}$ decays is recorded by the OKA collaboration. A missing mass analysis is performed to search for a light invisible pseudoscalar axion-like particle (ALP) $a$ in the decay $K^{+} \to \pi^{+} \pi^{0} a$. No signal is observed, the upper limits for the branching ratio of the decay are calculated. The $90\%$ confidence level upper limit is changing from $2.5\cdot10^{-6}$ to $2\cdot10^{-7}$ for the ALP mass from 0 to 200 MeV/$c^{2}$, except for the region of $\pi^{0}$ mass, where the upper limit is $4.4\cdot10^{-6}$.Comment: 6 pages, 6 figure

Observation of K+→π+π0π0γK^{+} \to \pi^{+}\pi^{0}\pi^{0}\gamma decay

The $K^{+} \to \pi^{+}\pi^{0}\pi^{0}\gamma$ decay is observed by the OKA collaboration. The branching ratio is measured to be $(4.1 \pm 0.9(stat) \pm 0.4(syst))\times 10^{-6}$. The branching ratio and $\gamma$ energy spectrum are consistent with ChPT prediction.Comment: arXiv admin note: text overlap with arXiv:2310.1642

Rapid selection of BRCA1-proficient tumor cells during neoadjuvant therapy for ovarian cancer in BRCA1 mutation carriers

Ovarian carcinomas (OC) often demonstrate rapid tumor shrinkage upon neoadjuvant chemotherapy (NACT). However, complete pathologic responses are very rare and the mechanisms underlying the emergence of residual tumor disease remain elusive. We hypothesized that the change of somatic BRCA1 status may contribute to this process. The loss-of-heterozygosity (LOH) at the BRCA1 locus was determined for 23 paired tumor samples obtained from BRCA1 germ-line mutation carriers before and after NACT. We observed a somatic loss of the wild-type BRCAI allele in 74% (17/23) of OCs before NACT. However, a retention of the wild-type BRCA1 copy resulting in a reversion of LOH status was detected in 65% (11/17) of those patients after NACT. Furthermore, we tested 3 of these reversion samples for LOH at intragenic BRCA1single nucleotide polymorphisms (SNPs) and confirmed a complete restoration of the SNP heterozygosity in all instances. The neoadjuvant chemotherapy for BRCA1-associated OC is accompanied by a rapid expansion of pre-existing BRCA1-proficient tumor clones suggesting that continuation of the same therapy after NACT and surgery may not be justified even in patients initially experiencing a rapid tumor regression. (C) 2017 Elsevier B.V. All rights reserved.Peer reviewe

Внутриопухолевая морфологическая и молекулярно-генетическая гетерогенность в астроцитомах разной степени злокачественности в материале от первой операции

Introduction. Intratumor heterogeneity is one of the key reasons for unfavourable prognosis in malignant tumors. Astrocytic tumors are known to develop therapy resistance inevitably during the course of disease. One of possible reason is tumor heterogeneity. Purpose. The aim of this work was to assess the intratumor morphologic and molecular heterogeneity in diffuse astrocytoma, anaplastic astrocytomas and primary glioblastomas. Material and methods. We conducted morphologic (n=22) and molecular-genetic (n=8) analysis of surgical specimens obtained from primarily operated glioblastoma giv (gb), anaplastic astrocytomas giii (aa) and diffuse astrocytoma gii (da) patients aged 18 years and older in whom total or subtotal tumor resection was performed. Tissue sampling for the analysis was performed from 5 equidistant areas of each tumor. Morphologic diagnosis was established according to who classification of central nervous system tumors (2007/2016). Mgmt, c-kit, top2a, pdgfr-α, ercc1, vegf genes mrnaexpression was assessed by rt-pcr. Idh1 and idh2 mutational status was evaluated by allele-specific pcr. Results. Morphologic heterogeneity was evident in 72,7 % tumors (16/22) overall. Heterogeneity was observed in 68,8 % (11/16) of gb, 80 % (4/5) of aa and in the only case of da. In 50 % of cases at least 3 different morphologic variants were seen in different areas of the tumor. This morphologic heterogeneity presented as the combination of different grades of anaplasia (gii – giv) in one tumor. Molecular profile was assessed in 48 expression analysis of genes: mgmt, c-kit, top2a, pdgfr-α, ercc1, vegf from 8 patients. Intratumoral molecular heterogeneity was revealed in 41,7 % of cases (20/48). Conclusion. The presence of intratumoral heterogeneity should be taken into account during surgery for adequate tumor sampling for histologic and molecular analysis which is critical for proper assessment of prognosis and following treatment planning.Введение. Внутриопухолевая гетерогенность является одним из ключевых факторов неблагоприятного прогноза в лечении пациентов со всеми онкологическими заболеваниями. Астроцитарные новообразования неизбежно рецидивируют с приобретением резистентности к дальнейшей терапии. Одна из возможных причин – это гетерогенность опухоли. Цель исследования – определить наличие морфологической и молекулярно-генетической гетерогенности в первичной глиобластоме, анапластической астроцитоме и диффузной астроцитоме. Материал и методы. Проведено проспективное исследование с анализом морфологических (n=22) и молекулярно-генетических характеристик (n=8) впервые прооперированных пациентов с глиобластомой giV (ГБ), анапластической астроцитомой giii (АА) и диффузной астроцитомой gii (ДА) в возрасте от 18 лет и старше. Забор образцов опухолевой ткани производился из 5 равноудаленных точек одного опухолевого узла при субтотальном и близко к тотальному удалении. Были получены 110 фрагментов опухолевой ткани. Гистологический диагноз ставился в каждом образце опухоли согласно классификации ВОЗ опухолей ЦНС (2007/2016). Относительная экспрессия мРНК генов: MGMT, C-kit, TOP2α, PDGFR-α, ERCC1, VEGF и мутации в генах IDH1 и IDH2 определялись при помощи ПЦР-методик. Результаты. Морфологическая внутриопухолевая гетерогенность была выявлена в 72,7 % случаев (16/22). В первичной ГБ гетерогенность наблюдалась в 68,8 % (11/16), в АА – в 80 % (4/5) и в единственном случае ДА. В 50 % случаев опухоль была гетерогенна в 3 и более фрагментах из пяти. Морфологическая гетерогенность представляла собой сочетание в одном опухолевом узле морфологических признаков астроцитом разной степени злокачественности – от ДА до ГБ. Внутриопухолевая молекулярно-генетическая гетерогенность была изучена у 8 пациентов в 48 экспрессионных анализах генов MGMT, C-kit, TOP2α, PDGFR-α, ERCC1, VEGF и наблюдалась в 41,7 % (20/48) случаев. Заключение. Присутствие внутриопухолевой гетерогенности следует учитывать во время операции для предоставления оптимального числа фрагментов опухоли на гистологическое и молекулярно-генетическое исследование, что имеет решающее значение для адекватной оценки прогноза и планирования лечения

Cost-Efficient Detection of <i>NTRK1/2/3</i> Gene Fusions: Single-Center Analysis of 8075 Tumor Samples

The majority of NTRK1, NTRK2, and NTRK3 rearrangements result in increased expression of the kinase portion of the involved gene due to its fusion to an actively transcribed gene partner. Consequently, the analysis of 5′/3′-end expression imbalances is potentially capable of detecting the entire spectrum of NTRK gene fusions. Archival tumor specimens obtained from 8075 patients were subjected to manual dissection of tumor cells, DNA/RNA isolation, and cDNA synthesis. The 5′/3′-end expression imbalances in NTRK genes were analyzed by real-time PCR. Further identification of gene rearrangements was performed by variant-specific PCR for 44 common NTRK fusions, and, whenever necessary, by RNA-based next-generation sequencing (NGS). cDNA of sufficient quality was obtained in 7424/8075 (91.9%) tumors. NTRK rearrangements were detected in 7/6436 (0.1%) lung carcinomas, 11/137 (8.0%) pediatric tumors, and 13/851 (1.5%) adult non-lung malignancies. The highest incidence of NTRK translocations was observed in pediatric sarcomas (7/39, 17.9%). Increased frequency of NTRK fusions was seen in microsatellite-unstable colorectal tumors (6/48, 12.5%), salivary gland carcinomas (5/93, 5.4%), and sarcomas (7/143, 4.9%). None of the 1293 lung carcinomas with driver alterations in EGFR/ALK/ROS1/RET/MET oncogenes had NTRK 5′/3′-end expression imbalances. Variant-specific PCR was performed for 744 tumors with a normal 5′/3′-end expression ratio: there were no rearrangements in 172 EGFR/ALK/ROS1/RET/MET-negative lung cancers and 125 pediatric tumors, while NTRK3 fusions were detected in 2/447 (0.5%) non-lung adult malignancies. In conclusion, this study describes a diagnostic pipeline that can be used as a cost-efficient alternative to conventional methods of NTRK1–3 analysis

Efficacy of lorlatinib in lung carcinomas carrying distinct ALK translocation variants: The results of a single-center study

Background: Lorlatinib is a novel potent ALK inhibitor, with only a few studies reporting the results of its clinical use. Methods: This study describes the outcomes of lorlatinib treatment for 35 non-small cell lung cancer patients with ALK rearrangements, who had 2 (n = 5), 1 (n = 26) or none (n = 4) prior tyrosine kinase inhibitors and received lorlatinib mainly within the compassionate use program. Results: Objective tumor response (OR) and disease control (DC) were registered in 15/35 (43%) and 33/35 (94%) patients, respectively; brain metastases were particularly responsive to the treatment (OR: 22/27 (81%); DC: 27/27 (100%)). Median progression free survival (PFS) was estimated to be 21.8 months, and median overall survival (OS) approached to 70.1 months. Only 4 out of 35 patients experienced no adverse effects; two of them were the only subjects who had no clinical benefit from lorlatinib. PFS and OS in the no-adverse-events lorlatinib users were strikingly lower as compared to the remaining patients (1.1 months vs. 23.7 months and 10.5 months vs. not reached, respectively; p < 0.0001 for both comparisons). ALK translocation variants were known for 28 patients; there was no statistical difference between patients with V.1 and V.3 rearrangements with regard to the OS or PFS. Conclusion: Use of lorlatinib results in excellent disease outcomes, however caution must be taken for patients experiencing no adverse effects from this drug