Corrigendum: Methylome changes in Lolium perenne associated with long-term colonisation by the endophytic fungus Epichloë sp. LpTG-3 strain AR37.

[This corrects the article DOI: 10.3389/fpls.2023.1258100.].

Methylome changes in Lolium perenne associated with long-term colonisation by the endophytic fungus Epichloë sp. LpTG-3 strain AR37.

Epichloë spp. often form mutualistic interactions with cool-season grasses, such as Lolium perenne. However, the molecular mechanisms underlying this interaction remain poorly understood. In this study, we employed reduced representation bisulfite sequencing method (epiGBS) to investigate the impact of the Epichloë sp. LpTG-3 strain AR37 on the methylome of L. perenne across multiple grass generations and under drought stress conditions. Our results showed that the presence of the endophyte leads to a decrease in DNA methylation across genomic features, with differentially methylated regions primarily located in intergenic regions and CHH contexts. The presence of the endophyte was consistently associated with hypomethylation in plants across generations. This research sheds new light on the molecular mechanisms governing the mutualistic interaction between Epichloë sp. LpTG-3 strain AR37 and L. perenne. It underscores the role of methylation changes associated with endophyte infection and suggests that the observed global DNA hypomethylation in L. perenne may be influenced by factors such as the duration of the endophyte-plant association and the accumulation of genetic and epigenetic changes over time.

Combined proteomics and CRISPR‒Cas9 screens in PDX identify ADAM10 as essential for leukemia in vivo.

BACKGROUND: Acute leukemias represent deadly malignancies that require better treatment. As a challenge, treatment is counteracted by a microenvironment protecting dormant leukemia stem cells. METHODS: To identify responsible surface proteins, we performed deep proteome profiling on minute numbers of dormant patient-derived xenograft (PDX) leukemia stem cells isolated from mice. Candidates were functionally screened by establishing a comprehensive CRISPR‒Cas9 pipeline in PDX models in vivo. RESULTS: A disintegrin and metalloproteinase domain-containing protein 10 (ADAM10) was identified as an essential vulnerability required for the survival and growth of different types of acute leukemias in vivo, and reconstitution assays in PDX models confirmed the relevance of its sheddase activity. Of translational importance, molecular or pharmacological targeting of ADAM10 reduced PDX leukemia burden, cell homing to the murine bone marrow and stem cell frequency, and increased leukemia response to conventional chemotherapy in vivo. CONCLUSIONS: These findings identify ADAM10 as an attractive therapeutic target for the future treatment of acute leukemias.

In vivo inducible reverse genetics in patients' tumors to identify individual therapeutic targets.

High-throughput sequencing describes multiple alterations in individual tumors, but their functional relevance is often unclear. Clinic-close, individualized molecular model systems are required for functional validation and to identify therapeutic targets of high significance for each patient. Here, we establish a Cre-ERT2-loxP (causes recombination, estrogen receptor mutant T2, locus of X-over P1) based inducible RNAi- (ribonucleic acid interference) mediated gene silencing system in patient-derived xenograft (PDX) models of acute leukemias in vivo. Mimicking anti-cancer therapy in patients, gene inhibition is initiated in mice harboring orthotopic tumors. In fluorochrome guided, competitive in vivo trials, silencing of the apoptosis regulator MCL1 (myeloid cell leukemia sequence 1) correlates to pharmacological MCL1 inhibition in patients´ tumors, demonstrating the ability of the method to detect therapeutic vulnerabilities. The technique identifies a major tumor-maintaining potency of the MLL-AF4 (mixed lineage leukemia, ALL1-fused gene from chromosome 4) fusion, restricted to samples carrying the translocation. DUX4 (double homeobox 4) plays an essential role in patients' leukemias carrying the recently described DUX4-IGH (immunoglobulin heavy chain) translocation, while the downstream mediator DDIT4L (DNA-damage-inducible transcript 4 like) is identified as therapeutic vulnerability. By individualizing functional genomics in established tumors in vivo, our technique decisively complements the value chain of precision oncology. Being broadly applicable to tumors of all kinds, it will considerably reinforce personalizing anti-cancer treatment in the future.

Fungal Endophyte Colonization Patterns Alter Over Time in the Novel Association Between Lolium perenne and Epichloë Endophyte AR37.

Infection of the pasture grass Lolium perenne with the seed-transmitted fungal endophyte Epichloë festucae enhances its resilience to biotic and abiotic stress. Agricultural benefits of endophyte infection can be increased by generating novel symbiotic associations through inoculating L. perenne with selected Epichloë strains. Natural symbioses have coevolved over long periods. Thus, artificial symbioses will probably not have static properties, but symbionts will coadapt over time improving the fitness of the association. Here we report for the first time on temporal changes in a novel association of Epichloë strain AR37 and the L. perenne cultivar Grasslands Samson. Over nine generations, a seed maintenance program had increased the endophyte seed transmission rates to > 95% (from an initial 76%). We observed an approximately fivefold decline in endophyte biomass concentration in vegetative tissues over time (between generations 2 and 9). This indicates strong selection pressure toward reducing endophyte-related fitness costs by reducing endophyte biomass, without compromising the frequency of endophyte transmission to seed. We observed no obvious changes in tillering and only minor transcriptomic changes in infected plants over time. Functional analysis of 40 plant genes, showing continuously decreasing expression over time, suggests that adaptation of host metabolism and defense mechanisms are important for increasing the fitness of this association, and possibly fitness of such symbioses in general. Our results indicate that fitness of novel associations is likely to improve over time and that monitoring changes in novel associations can assist in identifying key features of endophyte-mediated enhancement of host fitness.

In Vitro Evaluation of Antimicrobial Activity of Minocycline Formulations for Topical Application in Periodontal Therapy.

Periodontal therapy using antimicrobials that are topically applied requires slow or controlled release devices. The in vitro antimicrobial activity of biodegradable polymer formulations that contain a new minocycline lipid complex (P-MLC) was evaluated. The new P-MLC formulations that contained 11.5% minocycline were compared with pure minocycline or an existing commercial formulation, which included determination of minimal inhibitory concentration (MIC) values against two oral bacteria and activity on six-species periodontal biofilm. Moreover, the flow of gingival crevicular fluid (GCF) was modeled up to 42 d and the obtained eluates were tested both for MIC values and inhibiting biofilm formation. In general, MICs of the P-MLC formulations were slightly increased as compared with pure minocycline. Biofilm formation was clearly inhibited by all tested formulations containing minocycline with no clear difference between them. In 3.5 d old biofilms, all formulations with 250 µg/mL minocycline decreased bacterial counts by 3 log10 and metabolic activity with no difference to pure antimicrobials. Eluates of experimental formulations showed superiority in antimicrobial activity. Eluates of one experimental formulation (P503-MLC) still inhibited biofilm formation at 28 d, with a reduction by 1.87 log10 colony forming units (CFU) vs. the untreated control. The new experimental formulations can easily be instilled in periodontal pockets and represent alternatives in local antimicrobials, and thus warrant further testing.

Biological Roles of Protein-Coding Tandem Repeats in the Yeast Candida Albicans.

Tandem repeat (TR) DNA mutates faster than other DNA by insertion and deletion of repeats. Large parts of eukaryotic proteomes are encoded by ORFs containing protein-coding TRs (TR-ORFs, pcTRs) with largely unknown biological consequences. We explored these in the yeast Candida albicans, an opportunistic human pathogen. We found that almost half of C. albicans’ proteins are encoded by TR-ORFs. pcTR frequency differed only moderately between different gene (GO) categories. Bioinformatic predictions of genome-wide mutation rates and clade-specific differences in pcTR allele frequencies indicated that pcTRs (i) significantly increase the genome-wide mutation rate; (ii) significantly impact on fitness and (iii) allow the evolution of selectively advantageous clade-specific protein variants. Synonymous mutations reduced the repetitiveness of many amino acid repeat-encoding pcTRs. A survey, in 58 strains, revealed that in some pcTR regions in which repetitiveness was not significantly diminished by synonymous mutations the habitat predicted which alleles were present, suggesting roles of pcTR mutation in short-term adaptation and pathogenesis. In C. albicans pcTR mutation apparently is an important mechanism for mutational advance and possibly also rapid adaptation, with synonymous mutations providing a mechanism for adjusting mutation rates of individual pcTRs. Analyses of Arabidopsis and human pcTRs showed that the latter also occurs in other eukaryotes.

Multi-Locus Next-Generation Sequence Typing of DNA Extracted From Pooled Colonies Detects Multiple Unrelated Candida albicans Strains in a Significant Proportion of Patient Samples.

The yeast Candida albicans is an important opportunistic human pathogen. For C. albicans strain typing or drug susceptibility testing, a single colony recovered from a patient sample is normally used. This is insufficient when multiple strains are present at the site sampled. How often this is the case is unclear. Previous studies, confined to oral, vaginal and vulvar samples, have yielded conflicting results and have assessed too small a number of colonies per sample to reliably detect the presence of multiple strains. We developed a next-generation sequencing (NGS) modification of the highly discriminatory C. albicans MLST (multilocus sequence typing) method, 100+1 NGS-MLST, for detection and typing of multiple strains in clinical samples. In 100+1 NGS-MLST, DNA is extracted from a pool of colonies from a patient sample and also from one of the colonies. MLST amplicons from both DNA preparations are analyzed by high-throughput sequencing. Using base call frequencies, our bespoke DALMATIONS software determines the MLST type of the single colony. If base call frequency differences between pool and single colony indicate the presence of an additional strain, the differences are used to computationally infer the second MLST type without the need for MLST of additional individual colonies. In mixes of previously typed pairs of strains, 100+1 NGS-MLST reliably detected a second strain. Inferred MLST types of second strains were always more similar to their real MLST types than to those of any of 59 other isolates (22 of 31 inferred types were identical to the real type). Using 100+1 NGS-MLST we found that 7/60 human samples, including three superficial candidiasis samples, contained two unrelated strains. In addition, at least one sample contained two highly similar variants of the same strain. The probability of samples containing unrelated strains appears to differ considerably between body sites. Our findings indicate the need for wider surveys to determine if, for some types of samples, routine testing for the presence of multiple strains is warranted. 100+1 NGS-MLST is effective for this purpose.

Prognostic value of [18F]FDG-PET/CT in multiple myeloma patients before and after allogeneic hematopoietic cell transplantation.

PURPOSE: Despite improved treatment options, multiple myeloma (MM) remains an incurable disease. The aim of this study was to investigate the prognostic value of positron emission tomography/computed tomography (PET/CT) using 18F-2'-deoxy-2'-fluorodeoxyglucose ([18F]FDG) in MM patients shortly before and ~100 days after allogeneic hematopoietic cell transplantation (allo-HCT). METHODS: In this retrospective analysis, we evaluated [18F]FDG-PET/CT-scans of 45 heavily pre-treated MM patients before and 27 patients after scheduled allo-HCT. All scans were qualitatively and semi-quantitatively assessed for the presence of active disease. Serological response was recorded according to International Myeloma Working Group (IMWG) criteria. Progression-free (PFS) and overall survival (OS) were correlated with different PET/CT-derived parameters, such as presence, number and maximum standardized uptake value (SUVmax) of focal myeloma lesions. The impact of extramedullary disease on patient outcome was also assessed. RESULTS: PET/CT negativity -prior to or following allo-HCT- was a favorable prognostic factor for progression-free and overall survival (both, PFS and OS: pre-HSCT p < 0.001, post-HCT p < 0.005). High FDG-uptake (SUVmax > 6.5) revealed a significantly shortened survival compared to patients with a lower SUVmax (<6.5) (OS, 5.0 ± 1.1 m vs. not reached - longest 122.0 m; p < 0.001). Moreover, our data prove that a higher number (>3) of focal lesions (pre-HCT: both PFS and OS: p < 0.001; post-HCT PFS: p < 0.001, OS: p = 0.139) as well as the presence of extramedullary disease serve as adverse prognostic factors prior to and after allo-HCT. At response assessment after allo-HCT, [18F]FDG-PET/CT had a complementary value in prognostication in addition to IMWG criteria alone. CONCLUSION: [18F]FDG-PET/CT before and shortly after allogeneic HCT is a powerful predictor for progression-free and overall survival in MM patients.

Initial Clinical Investigation of [18F]Tetrafluoroborate PET/CT in Comparison to [124I]Iodine PET/CT for Imaging Thyroid Cancer.

AIM: Recently, [F]tetrafluoroborate ([F]TFB) has been introduced as a versatile PET probe for imaging the human sodium/iodide symporter activity. This pilot study aimed to compare [F]TFB-PET/CT with [I]NaI-PET/CT imaging in thyroid cancer patients. METHODS: Nine patients with newly diagnosed differentiated thyroid cancer underwent both [F]TFB- and [I]NaI-PET/CT after total thyroidectomy. PET/CT scans were visually analyzed for the presence of remnant thyroid tissue and for metastatic lesions on a patient and lesion basis. For semiquantitative analysis, thyroid remnant/tumor to blood pool ratios were calculated. RESULTS: All patients presented with positive [F]TFB and [I]NaI-PET/CT scans. Retention of I in remnant thyroid tissue was significantly higher as compared with [F]TFB (P < 0.01). In a lesion-based analysis, both tracers identified an almost equal number of foci with [F]TFB depicting a total of 41 foci and I a total of 40 foci, respectively. In 6 of 9 patients, both radiopharmaceuticals returned an identical number of foci. Two I-positive benign thyroid remnants were missed by [F]TFB-PET/CT in a single patient. In another case, both tracers identified different thyroid remnant tissues in the cervical region. Notably, [F]TFB demonstrated additional (I-negative) cervical lymph node metastases in 2 patients, leading to an overall agreement between the radiotracers of 91% (74/81 foci). DISCUSSION: In this pilot study, [F]TFB-PET was not inferior to [I]NaI-PET for detecting thyroid cancer and its metastases and was able to detect [I]NaI-PET-negative viable differentiated thyroid cancer metastases. Further clinical evaluation as a PET tracer for imaging thyroid pathophysiology and human sodium/iodide symporter expressing neoplasms is highly warranted.

Predictive Value of 18F-FDG PET in Patients with Advanced Medullary Thyroid Carcinoma Treated with Vandetanib.

Therapeutic options in advanced medullary thyroid carcinoma (MTC) have markedly improved since the introduction of tyrosine kinase inhibitors (TKIs). We aimed to assess the role of metabolic imaging using 18F-FDG PET/CT shortly before and 3 mo after initiation of TKI treatment. Methods: Eighteen patients with advanced and progressive MTC scheduled for vandetanib treatment underwent baseline 18F-FDG PET/CT before and 3 mo after TKI treatment initiation. During follow-up, CT scans were obtained every 3 mo and analyzed according to RECIST. The predictive value for estimating progression-free survival (PFS) and overall survival (OS) was examined by investigating the 18F-FDG SUVmean/max of the metabolically most active lesion, as well as by analyzing clinical parameters (tumor marker doubling times [calcitonin, carcinoembryonic antigen], prior therapies, rearranged-during-transfection mutational status, and disease type). Results: Within a median follow-up of 5.2 y, 9 patients experienced disease progression after a median interval of 2.1 y, whereas the remainder had ongoing disease control (5 with a partial response and 4 with stable disease). Eight of the 9 patients with progressive disease died from MTC after a median of 3.5 y after TKI initiation. A pretherapeutic SUVmean of more than 4.0 predicted a significantly shorter PFS (1.9 y vs. 5.2 y, P = 0.04). Furthermore, sustained high 18F-FDG uptake at 3 mo with a SUVmean of more than 2.8 tended to portend an unfavorable prognosis, with a PFS of 1.9 y (vs. 3.5 y, P = 0.3). Prolonged carcinoembryonic antigen doubling times were significantly correlated with longer PFS (r = 0.7) and OS (r = 0.76, P < 0.01). None of the other clinical parameters had prognostic significance. Conclusion: Pretherapeutic 18F-FDG PET/CT provides prognostic information in patients with advanced MTC scheduled for treatment with the TKI vandetanib. A low tumor metabolism with an SUVmean of less than 4.0 before treatment predicts a longer PFS.

11C-Methionine-PET in Multiple Myeloma: A Combined Study from Two Different Institutions.

11C-methionine (MET) has recently emerged as an accurate marker of tumor burden and disease activity in patients with multiple myeloma (MM). This dual-center study aimed at further corroboration of the superiority of MET as positron emission tomography (PET) tracer for staging and re-staging MM, as compared to 18F-2`-deoxy-2`-fluoro-D-glucose (FDG). 78 patients with a history of solitary plasmacytoma (n=4), smoldering MM (SMM, n=5), and symptomatic MM (n=69) underwent both MET- and FDG-PET/computed tomography (CT) at the University Centers of Würzburg, Germany and Navarra, Spain. Scans were compared on a patient and on a lesion basis. Inter-reader agreement was also evaluated. In 2 patients, tumor biopsies for verification of discordant imaging results were available. MET-PET detected focal lesions (FL) in 59/78 subjects (75.6%), whereas FDG-PET/CT showed lesions in only 47 patients (60.3%; p<0.01), accordingly disease activity would have been missed in 12 patients. Directed biopsies of discordant results confirmed MET-PET/CT results in both cases. MET depicted more FL in 44 patients (56.4%; p<0.01), whereas in two patients (2/78), FDG proved superior. In the remainder (41.0%, 32/78), both tracers yielded comparable results. Inter-reader agreement for MET was higher than for FDG (κ = 0.82 vs κ = 0.72). This study demonstrates higher sensitivity of MET in comparison to standard FDG to detect intra- and extramedullary MM including histologic evidence of FDG-negative, viable disease exclusively detectable by MET-PET/CT. MET holds the potential to replace FDG as functional imaging standard for staging and re-staging of MM.

Highly mutable tandem DNA repeats generate a cell wall protein variant more frequent in disease-causing Candida albicans isolates than in commensal isolates.

During adaptation to host environments, many microorganisms alter their cell surface. One mechanism for doing so is variation in the number of amino acid repeats in cell surface proteins encoded by hypermutable DNA tandem repeats. In the yeast Candida albicans, an opportunistic human pathogen, the gene SSR1 encodes a GPI-anchored cell wall protein with a structural role. It contains two regions consisting of tandem repeats, almost exclusively encoding the amino acid pair Ser-Ala. As expected, the repeat regions make SSR1 highly mutable. New SSR1 alleles arose with a frequency of 1.11×10-4 per cell division in serially propagated cells. We also observed a large number (25) of SSR1 alleles with different repeat lengths in a survey of 131 isolates from a global strain collection. C. albicans is diploid, and combinations of these allele generated 41 different SSR1 genotypes. In both repeat regions, nonsynonymous mutations were largely restricted to one particular repeat unit. Two very similar allele combinations were largely restricted to one clade, clade 1. Each combination was present in ~30% of 49 infection-causing clade 1 strains, but one was rare (2%), the other absent in 46 infection-causing strains representing the remainder of the species (P < 0.00018 and 0.00004; Fisher's exact test). These results indicate that both repeat regions are under selection and that amino acid repeat length polymorphisms generate Ssr1 protein variants most suitable for specific genetic backgrounds. One of these two allele combinations was 5.51 times more frequent, the other 1.75 times less frequent in 49 clade 1 strains that caused disease than in 36 commensal clade 1 strains (P = 0.0105; Chi2 test). This indicates that insertion and deletion of repeats not only generates clade-optimized Ssr1p variants, but may also assist in short-term adaptation when C. albicans makes the transition from commensal to pathogen.

Imaging of Chemokine Receptor 4 Expression in Neuroendocrine Tumors - a Triple Tracer Comparative Approach.

C-X-C motif chemokine receptor 4 (CXCR4) and somatostatin receptors (SSTR) are overexpressed in gastro-entero-pancreatic neuroendocrine tumors (GEP-NET). In this study, we aimed to elucidate the feasibility of non-invasive CXCR4 positron emission tomography/computed tomography (PET/CT) imaging in GEP-NET patients using [68Ga]Pentixafor in comparison to 68Ga-DOTA-D-Phe-Tyr3-octreotide ([68Ga]DOTATOC) and 18F-fluorodeoxyglucose ([18F]FDG). Twelve patients with histologically proven GEP-NET (3xG1, 4xG2, 5xG3) underwent [68Ga]DOTATOC, [18F]FDG, and [68Ga]Pentixafor PET/CT for staging and planning of the therapeutic management. Scans were analyzed on a patient as well as on a lesion basis and compared to immunohistochemical staining patterns of CXCR4 and somatostatin receptors SSTR2a and SSTR5. [68Ga]Pentixafor visualized tumor lesions in 6/12 subjects, whereas [18F]FDG revealed sites of disease in 10/12 and [68Ga]DOTATOC in 11/12 patients, respectively. Regarding sensitivity, SSTR-directed PET was the superior imaging modality in all G1 and G2 NET. CXCR4-directed PET was negative in all G1 NET. In contrast, 50% of G2 and 80% of G3 patients exhibited [68Ga]Pentixafor-positive tumor lesions. Whereas CXCR4 seems to play only a limited role in detecting well-differentiated NET, increasing receptor expression could be non-invasively observed with increasing tumor grade. Thus, [68Ga]Pentixafor PET/CT might serve as non-invasive read-out for evaluating the possibility of CXCR4-directed endoradiotherapy in advanced dedifferentiated SSTR-negative tumors.

Host Tissue Environment Directs Activities of an Epichloë Endophyte, While It Induces Systemic Hormone and Defense Responses in Its Native Perennial Ryegrass Host.

Increased resilience of pasture grasses mediated by fungal Epichloë endophytes is crucial to pastoral industries. The underlying mechanisms are only partially understood and likely involve very different activities of the endophyte in different plant tissues and responses of the plant to these. We analyzed the transcriptomes of Epichloë festucae and its host, Lolium perenne, in host tissues of different function and developmental stages. The endophyte contributed approximately 10× more to the transcriptomes than to the biomass of infected tissues. Proliferating mycelium in growing host tissues highly expressed genes involved in hyphal growth. Nonproliferating mycelium in mature plant tissues, transcriptionally equally active, highly expressed genes involved in synthesizing antiherbivore compounds. Transcripts from the latter accounted for 4% of fungal transcripts. Endophyte infection systemically but moderately increased transcription of L. perenne genes with roles in hormone biosynthesis and perception as well as stress and pathogen resistance while reducing expression of genes involved in photosynthesis. There was a good correlation between transcriptome-based observations and physiological observations. Our data indicate that the fitness-enhancing effects of the endophyte are based both on its biosynthetic activities, predominantly in mature host tissues, and also on systemic alteration of the host's hormonal responses and induction of stress response genes. [Formula: see text] Copyright © 2017 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

Fusion of freehand SPECT and ultrasound: First experience in preoperative localization of sentinel lymph nodes.

PURPOSE: Radioguided sentinel lymph node biopsy (SLNB) is the standard of care in breast cancer and melanoma. Additional preoperative Single-photon emission computed tomography (SPECT/CT) for improved anatomical co-registration of the SLNs causes additional radiation exposure and is time-consuming and expensive. The aim of this prospective study was to evaluate a novel approach involving real-time fusion of freehand SPECT (fhSPECT) and ultrasound (US) for anatomical co-registration of SLNs. METHODS: From February 2015 to February 2016, 153 patients were included in this prospective study. All patients underwent lymphoscintigraphy according to practical guidelines and 151 (118 cases of breast cancer, 30 cutaneous malignancies, and three cases of vulvar cancer) of the 153 patients were additionally investigated with fhSPECT-US. FhSPECT connected to a hand-held gamma detector generates three-dimensional images of the radioactivity distribution in the scanned area. For co-registration and real-time fusion of fhSPECT and subsequently performed US, an infrared stereo tracking system was used. RESULTS: In all patients an SLN was found on lymphoscintigraphy, and the fhSPECT detected corresponding hotspots in all but one patient. In 72 % of patients and 73 % of lymph node basins, real-time anatomical co-registration with US was feasible. The rate of success in achieving good co-registration increased from 60 to 75 % after training by a radiologist specialized in breast imaging. A higher co-registration rate (78 %) was observed in patients with only one SLN than in those with two SLNs (68 %) or three or more SLNs (0 %). CONCLUSIONS: Real-time fusion of fhSPECT and US for preoperative anatomical co-registration of SLNs is feasible. However, before this approach can completely replace preoperative lymphatic imaging, further technical developments are needed.

Recurrent Extrahepatic Hepatocellular Carcinoma Detected by 18F-Choline PET/CT.

Diagnosis of recurrent hepatocellular carcinoma (HCC) is sometimes challenging, especially when extrahepatic disease is present. Here, we report on a 49-year-old woman with a history of HCC who was referred to our institution with suspicion of tumor recurrence for further workup. Combined F-choline PET/CT revealed a soft tissue mass at the right thoracic wall highly consistent with HCC.

[68Ga]Pentixafor-PET/CT for imaging of chemokine receptor 4 expression in small cell lung cancer--initial experience.

Chemokine receptor CXCR4 is a key factor for tumor growth and metastasis in several types of human cancer. This study investigated the feasibility of CXCR4-directed imaging of small cell lung cancer (SCLC) with positron emission tomography/computed tomography (PET/CT) using the radiolabelled chemokine ligand [68Ga]Pentixafor. 10 patients with primarily diagnosed (n=3) or pre-treated (n=7) SCLC (n=9) or large cell neuroendocrine carcinoma of the lung (LCNEC, n=1) underwent [68Ga]Pentixafor-PET/CT. 2-[18F]fluoro-2-deoxy-D-glucose ([18F]FDG, n=6) and/or somatostatin receptor (SSTR)-directed PET/CT with [68Ga]DOTATOC (n=5) and immunohistochemistry (n=10) served as standards of reference. CXCR4-PET was positive in 8/10 patients and revealed more lesions with significantly higher tumor-to-background ratios than SSTR-PET. Two patients who were positive on [18F]FDG-PET were missed by CXCR4-PET, in the remainder [68Ga]Pentixafor detected an equal (n=2) or higher (n=2) number of lesions. CXCR4 expression of tumor lesions could be confirmed by immunohistochemistry. Non-invasive imaging of CXCR4 expression in SCLC is feasible. [68Ga]Pentixafor as a novel PET tracer might serve as readout for confirmation of CXCR4 expression as prerequisite for potential CXCR4-directed treatment including receptor-radio(drug)peptide therapy.

Last hope for the doomed? Thoughts on the importance of a parasexual cycle for the yeast Candida albicans.

The yeast Candida albicans, a commensal colonizer and occasional pathogen of humans, has a rudimentary mating ability. However, mating is a cumbersome process that has never been observed outside the laboratory, and the population structure of the species is predominantly clonal. Here we discuss recent findings that indicate that mating ability is under selection in C. albicans, i.e. that it is a biologically relevant process. C. albicans strains can only mate after they have sustained genetic damage. We propose that the rescue of such damaged strains by mating may be the primary reason why mating ability is under selection.