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Mills, G.

Publications and source records attributed to Mills, G..

17 recordsLinked to original sources

Tumor-intrinsic MHC-II activation in pancreatic ductal adenocarcinoma enhances immune response and treatment efficacy

Pancreatic ductal adenocarcinoma (PDAC) is characterized by an immunosuppressive tumor microenvironment (TME) and poor prognosis. While major histocompatibility complex class II (MHC-II) expression is traditionally associated with professional antigen-presenting cells, its role in PDAC malignant cells remains underexplored. Herein, we utilized single-cell RNA sequencing (scRNA-seq), spatial transcriptomics, bulk RNA sequencing, multiplex immunohistochemistry (mIHC) and ex vivo studies in culture with both human and murine models to investigate the prognostic relevance of MHC-II expression in malignant PDAC cells. Elevated MHC-II expression in malignant cells was strongly associated with increased infiltration of CD4+ T and CD8+ T cells in human PDAC, and pronounced co-localization with plasma cells, indicative of an antigen-activated immune microenvironment. In the KPC mouse model of PDAC, pharmacologic induction of MHC-II expression by cobimetinib treatment in malignant epithelial cells significantly enhanced the therapeutic response to immune checkpoint blockade (ICB). These findings highlight the role of malignant cell- intrinsic MHC-II expression in promoting antigen presentation and fostering an anti-tumor immune microenvironment. Our results position MHC-II as a promising prognostic biomarker and therapeutic target in PDAC, paving the way for novel immunomodulatory strategies. Summary of highlightsSingle-cell and spatial transcriptomic analyses reveal that elevated MHC-II expression in malignant PDAC cells correlates with increased infiltration of CD4 and CD8 T cells. Stimulating MHC-II expression in tumors effectively enhances immunotherapeutic responses to ICB in the PDAC KPC mouse model, including PDAC tumors previously resistant to therapeutic interventions. MHC-II serves as a prognostic biomarker and a promising target for immunotherapy in PDAC.

cancer biology↗

Sensitizing Immune-Refractory Ovarian Tumors via p53 Mutation-Tailored Immunotherapy

High-grade serous ovarian cancer demonstrates limited responsiveness to immune checkpoint inhibitors, owing in part to immunosuppressive environments shaped by nearly universal p53 aberrations. Utilizing an immunocompetent mouse model and individual p53 mutations, we identified a dependence of the p53-R270H mutation (equivalent of human R273H) on regulatory T cells (Tregs) and the PD-1/PD-L1 axis. Analysis of patient datasets associated R273H with elevated levels of two p53 targets, PD-L1 and amphiregulin (AREG), a Tregs growth factor. In contrast to p53-R172H tumors, where there was limited activity, dual antibody therapy targeting AREG and PD-L1 selectively and effectively inhibited R270H tumors. This involved polarization toward M1 macrophages, infiltration of CD8+ T cells, diminished Ly6G+ neutrophils and downregulation of interleukin-4. In patient-derived R273C organoids, the combination treatment reduced the CD4/CD8 ratio. This study is the first to establish a mutation-tailored therapeutic approach that leverages the capacity of p53 to modulate immunosuppressive mechanisms.

cancer biology↗

Klebsiella pneumoniae remodels its Kdo2-lipid A in a TLR4-dependent manner to adapt to the macrophage intracellular environment

Pathogen adaptations to the intracellular macrophage environment remain poorly understood. We performed a high-resolution structural analysis of the lipid A purified from intracellular Klebsiella pneumoniae (KP). In both mouse and human macrophages, KP produces hexa- and hepta-acylated lipid A species modified with palmitate and 2-hydroxylated. LpxL1, PagP, and LpxO enzymes govern the intracellular lipid A in a PhoPQ-dependent manner triggered by the acidic pH of the KP-containing vacuole (KCV). Absence of LpxO and PagP lipid A modifications impairs intracellular survival and heightens NF-{kappa}B and IRF3-mediated inflammation, though KCV maturation remains unaffected. Instead, these modifications fortify the bacterial membrane. Absence of TLR4-TRAM-TRIF signalling increases KCV pH, impairing the production of the intracellular lipid A. KP intracellular survival is reduced in tlr4-/- macrophages, highlighting the critical role of this signalling pathway in KP immune evasion and how the pathogen has evolved to rely on innate immune system cues for virulence.

microbiology↗

Replay of procedural experience is independent of the hippocampus

Sleep is critical for consolidating all forms of memory1-3, from episodic experience to the development of motor skills4-6. A core feature of the consolidation process is offline replay of neuronal firing patterns that occur during experience7,8. This replay is thought to originate in the hippocampus and trigger the reactivation of ensembles of cortical and subcortical neurons1,3,9-18. However, non-declarative memories do not require the hippocampus for learning or for sleep-dependent consolidation19-26 meaning what drives their consolidation is unknown. Here we show, using an unsupervised method, that replay occurs in the dorsal striatum of mice during offline consolidation of a non-declarative, procedural, memory and that this replay is generated independently of the hippocampus. Replay occurred at both real-world and time-compressed speeds and was also prioritised both at the level of the individual neurons and the type of neural sequence. Complete bilateral lesions of the hippocampus had no effect on any feature of this replay. Our results demonstrate that procedural replay during consolidation of a non-declarative memory is independent of the hippocampus. These results support the view that replay drives active consolidation of all types of memory during sleep but challenges the idea that the hippocampus is the source of this replay.

neuroscience↗

Androgen receptor activity inversely correlates with immune cell infiltration and immunotherapy response across multiple cancer lineages

There is now increasing recognition of the important role of androgen receptor (AR) in modulating immune function. To gain a comprehensive understanding of the effects of AR activity on cancer immunity, we employed a computational approach to profile AR activity in 33 human tumor types using RNA-Seq datasets from The Cancer Genome Atlas. Our pan-cancer analysis revealed that the genes most negatively correlated with AR activity across cancers are involved in active immune system processes. Importantly, we observed a significant negative correlation between AR activity and IFN{gamma} pathway activity at the pan-cancer level. Indeed, using a matched biopsy dataset from subjects with prostate cancer before and after AR-targeted treatment, we verified that inhibiting AR enriches immune cell abundances and is associated with higher IFN{gamma} pathway activity. Furthermore, by analyzing immunotherapy datasets in multiple cancers, our results demonstrate that low AR activity was significantly associated with a favorable response to immunotherapy. Together, our data provide a comprehensive assessment of the relationship between AR signaling and tumor immunity.

cancer biology↗

Explainable Machine Learning Reveals the Role of the Breast Tumor Microenvironment in Neoadjuvant Chemotherapy Outcome

Recent advancements in single-cell RNA sequencing (scRNA-seq) have enabled the identification of phenotypic diversity within breast tumor tissues. However, the contribution of these cell phenotypes to tumor biology and treatment response has remained less understood. This is primarily due to the limited number of available samples and the inherent heterogeneity of breast tumors. To address this limitation, we leverage a state-of-the-art scRNA-seq atlas and employ CIBER-SORTx to estimate cell phenotype fractions by de-convolving bulk expression profiles in more than 2000 samples from patients who have undergone Neoad-juvant Chemotherapy (NAC). We introduce a pipeline based on explainable Machine Learning (XML) to robustly explore the associations between different cell phenotype fractions and the response to NAC in the general population as well as different subtypes of breast tumors. By comparing tumor subtypes, we observe that multiple cell types exhibit a distinct association with pCR within each subtype. Specifically, Dendritic cells (DCs) exhibit a negative association with pathological Complete Response (pCR) in Estrogen Receptor positive, ER+, (Luminal A/B) tumors, while showing a positive association with pCR in ER-(Basal-like/HER2-enriched) tumors. Analysis of new spatial cyclic immunoflu-orescence data and publicly available imaging mass cytometry data showed significant differences in the spatial distribution of DCs between ER subtypes. These variations underscore disparities in the engagement of DCs within the tumor microenvironment (TME), potentially driving their divergent associations with pCR across tumor subtypes. Overall, our findings on 28 different cell types provide a comprehensive understanding of the role played by cellular compo-nents of the TME in NAC outcomes. They also highlight directions for further experimental investigations at a mechanistic level.

bioinformatics↗

Selective enrichment of plasma cell-free messenger RNA in cancer-associated extracellular vesicles

Extracellular vesicles (EVs) have been shown as key mediators of extracellular small RNA transport. However, carriers of cell-free messenger RNA (cf-mRNA) in human biofluid and their association with cancer remain poorly understood. Here, we performed a transcriptomic analysis of size-fractionated plasma from lung cancer, liver cancer, multiple myeloma, and healthy donors. Morphology and size distribution analysis showed the successful separation of medium and small EVs and non-vesicular carriers. We developed a strategy to purify and sequence ultra-low amounts of cf-mRNA from vesicular and non-vesicular subpopulations with the implementation of RNA spike-ins to control for technical variability and to normalize for intrinsic drastic differences in the amount of cf-mRNA carried in each plasma fraction. We found that the majority of cf-mRNA was enriched and protected in EVs with remarkable stability in RNase-rich environments. We observed specific enrichment patterns of cancer-associated cf-mRNA in each vesicular and non-vesicular subpopulation. The EV-enriched differentiating genes were associated with specific biological pathways, such as immune systems, liver function, and toxic substance regulation in lung cancer, liver cancer, and multiple myeloma, respectively. Our results suggest that dissecting the complexity of EVs subpopulations illuminates their biological significance and offers a promising liquid biopsy approach.

genomics↗

Structure of the Lysinibacillus sphaericus Tpp49Aa1 pesticidal protein elucidated from natural crystals using MHz-SFX

Tpp49Aa1 from Lysinibacillus sphaericus is a Toxin_10 family protein that - in combination with Cry48Aa1, a 3-domain crystal protein - has potent mosquitocidal activity, specifically against Culex quinquefasciatus mosquitoes. MHz serial femtosecond crystallography at a nano-focused X-ray free electron laser, allowed rapid and high-quality data collection to determine the Tpp49Aa1 structure at 1.62 [A] resolution from native nanocrystals. This revealed the packing of Tpp49Aa1 within these nanocrystals, isolated from sporulated bacteria, as a homodimer with a large intermolecular interface, shedding light on natural crystallization. Complementary experiments conducted at varied pH also enabled investigations of the early structural events leading up to the dissolution of natural Tpp49Aa1 crystals. Using modelling, we propose a potential interaction between Tpp49Aa1 and Cry48Aa1 that may play a role in their codependency and broaden our understanding of this two-component system. We expand the known target range, demonstrating Tpp49Aa1/Cry48Aa1 susceptibility of larvae from Anopheles stephensi, Aedes albopictus and Culex tarsalis - substantially increasing the potential use of this toxin pair in mosquito control. Further functional insights are gained using Culex cell lines to characterise cellular models for future investigations into Cry48Aa1/Tpp49Aa1 mechanism of action and to demonstrate transient detrimental effects of individual toxin components. Significance StatementThe Tpp49Aa1/Cry48Aa1 protein pair kills mosquito larvae. Innovative use of nano-focused X-ray free electron laser to match the size of natural Tpp49Aa1 nanocrystals and the highest beam intensity available in any XFEL for high-throughput data collection, allowed structural resolution to 1.62 [A]. Tpp proteins show a range of interactions with different partners to elicit toxicity. To gain insight into Tpp49Aa1, its interaction with Cry48Aa1 was modelled. We also establish cell-based assays of Tpp49Aa1/Cry48Aa1 activity. We expand the known target range to include three more mosquito species: Anopheles stephensi, Aedes albopictus and Culex tarsalis. This study will underpin future Tpp mode of action investigations and aid insecticide optimization against mosquito vectors of emerging diseases such as West Nile Virus and malaria.

biochemistry↗

In vivo single cell transcriptomics reveals Klebsiella pneumoniae rewiring of lung macrophages to promote infection

The strategies deployed by antibiotic resistant bacteria to counteract host defences are poorly understood. Here, we elucidate a novel host-pathogen interaction that results in the control of lung macrophage polarisation by the human pathogen Klebsiella pneumoniae. We identify interstitial macrophages (IMs) as the main population of lung macrophages associated with Klebsiella. Single cell transcriptomics and trajectory analysis of cells uncover that type I IFN and IL10 signalling, and macrophage polarization are characteristic of infected IMs, whereas Toll-like receptor (TLR) and Nod-like receptor signalling are features of infected alveolar macrophages. Klebsiella-induced macrophage polarization is a singular M2-type we termed M(Kp). To rewire macrophages towards M(Kp), K. pneumoniae hijacks a hitherto unknown TLR-type I IFN-IL10-STAT6 innate axis. Absence of STAT6 limits the intracellular survival of Klebsiella whereas the inhibition of STAT6 facilitates the clearance of the pathogen in vivo. Glycolysis characterises M(Kp) metabolism, and inhibition of glycolysis results in clearance of intracellular Klebsiella. We demonstrate the capsule polysaccharide is the Klebsiella factor governing M(Kp). Klebsiella also skews human macrophage polarization towards M(Kp) in a type I IFN-IL10-STAT6-dependent manner. Altogether, our work demonstrates that Klebsiella induction of M(Kp) represents a hitherto unknown strategy to overcome host restriction during pneumonia.

microbiology↗

Flight-tone mediated circadian control of audibility in mating swarms of Anopheles mosquitoes

Mating swarms of malaria mosquitoes form every day at sunset throughout the tropical world, they typically last less than 30 minutes. Activity patterns must thus be highly synchronized between the sexes. Moreover, males must be able to identify the few sporadically entering females by detecting the females faint flight tones. We here show that the Anopheles circadian clock ensures a tight synchrony of male and female activity and -importantly - also retunes the males acoustic detection system: by lifting their own flight tones at dusk, males actively enhance the audibility of females. The reported phenomenon of harmonic convergence is a random by-product of the mosquitoes flight tone variance. Intriguingly, flight tones of individual mosquitoes occupy narrow -partly non-overlapping-frequency ranges, suggesting that the audibility of individual females varies across males. One Sentence SummaryMale mosquitoes sharpen their hearing at sunset.

neuroscience↗

Spatially Interacting Phosphorylation Sites and Mutations in Cancer

Advances in mass-spectrometry have generated increasingly large-scale proteomics datasets containing tens of thousands of phosphorylation sites (phosphosites) that require prioritization. We develop a bioinformatics tool called HotPho and systematically discover 3D co-clustering of phosphosites and cancer mutations on protein structures. HotPho identifies 474 such hybrid clusters containing 1,255 co-clustering phosphosites, including RET p.S904/Y928, the conserved HRAS/KRAS p.Y96, and IDH1 p.Y139/IDH2 p.Y179 that are adjacent to recurrent mutations on protein structures not found by linear proximity approaches. Hybrid clusters, enriched in histone and kinase domains, frequently include expression-associated mutations experimentally shown as activating and conferring genetic dependency. Approximately 300 co-clustering phosphosites are verified in patient samples of 5 cancer types or previously implicated in cancer, including CTNNB1 p.S29/Y30, EGFR p.S720, MAPK1 p.S142, and PTPN12 p.S275. In summary, systematic 3D clustering analysis highlights nearly 3,000 likely functional mutations and over 1,000 cancer phosphosites for downstream investigation and evaluation of potential clinical relevance.

bioinformatics↗

Reward enhances online participants' engagement with a demanding auditory task

Online recruitment platforms are increasingly utilized for experimental research. Crowdsourcing is associated with numerous benefits but also notable constraints, including lack of control over participants environment and engagement. In the context of auditory experiments, these limitations may be particularly detrimental to threshold-based tasks that require effortful listening. Here, we ask whether incorporating a performance-based monetary bonus will improve speech reception performance of online participants. In two experiments, participants performed an adaptive matrix-type speech-in-noise task (where listeners select two key words out of closed sets). In Experiment 1, our results revealed worse performance in online (N = 49) compared with in-lab (N = 81) groups. Specifically, relative to the in-lab cohort, significantly fewer participants in the online group achieved very low (< -17dB) thresholds. In Experiment 2 (N = 200), we show that a monetary reward improved listeners threshold to levels similar to those observed in the lab setting. Overall the results suggest that providing a small performance-based bonus increases participants task-engagement, facilitating a more accurate estimation of auditory ability under challenging listening conditions.

neuroscience↗

Direct Observation of the Mechanism of Antibiotic Resistance by Mix-and-Inject at the European XFEL

In this study, we follow the diffusion and buildup of occupancy of the substrate ceftriaxone in M. tuberculosis {beta}-lactamase BlaC microcrystals by structural analysis of the enzyme substrate complex at single millisecond time resolution. We also show the binding and the reaction of an inhibitor, sulbactam, on a slower millisecond time scale. We use the mix-and-inject technique to initiate these reactions by diffusion, and determine the resulting structures by serial crystallography using ultrafast, intense X-ray pulses from the European XFEL (EuXFEL) arriving at MHz repetition rates. Here, we show how to use the EuXFEL pulse structure to dramatically increase the size of the data set and thereby the quality and time resolution of "molecular movies" which unravel ligand binding and enzymatically catalyzed reactions. This shows the great potential for the EuXFEL as a tool for biomedically relevant research, particularly, as shown here, for investigating bacterial antibiotic resistance. One Sentence SummaryDirect observation of fast ligand binding in a biomedically relevant enzyme at near atomic resolution with MHz X-ray pulses at the European XFEL.

biophysics↗

Large-scale Characterization of Drug Responses of Clinically Relevant Proteins in Cancer Cell Lines

Perturbation biology is a powerful approach to developing quantitative models of cellular behaviors and gaining mechanistic insights into disease development. In recent years, large-scale resources for phenotypic and mRNA responses of cancer cell lines to perturbations have been generated. However, similar large-scale protein response resources are not available, resulting in a critical knowledge gap for elucidating oncogenic mechanisms and developing effective cancer therapies. Here we generated and compiled perturbed expression profiles of ~210 clinically relevant proteins in >12,000 cancer cell-line samples in response to >150 drug compounds using reverse-phase protein arrays. We show that integrating protein response signals substantially increases the predictive power for drug sensitivity and aids in gaining insights into mechanisms of drug resistance. We build a systematic map of protein-drug connectivity and develop an open-access, user-friendly data portal for community use. Our study provides a valuable information resource for a broad range of quantitative modeling and biomedical applications. HighlightsO_LIA large collection of cancer cell line protein responses to drug perturbations C_LIO_LIPerturbed protein responses greatly increase predictive power for drug sensitivity C_LIO_LIBuild a systematic map of protein-drug connectivity based on response profiles C_LIO_LIDevelop a user-friendly, interactive data portal for community use C_LI

systems biology↗

In vitro evolution of colistin resistance in the Klebsiella pneumoniae complex follows multiple evolutionary trajectories with variable effects on fitness and virulence characteristics.

The increasing prevalence of multidrug-resistant Gram-negative opportunistic pathogens, including Klebsiella pneumoniae, has led to a resurgence in the use of colistin as a last-resort drug. Colistin is a cationic lipopeptide antibiotic that selectively acts on Gram-negative bacteria through electrostatic interactions with anionic phosphate groups of the lipid A moiety of lipopolysaccharides (LPS). Colistin resistance in K. pneumoniae is mediated through loss of these phosphate groups, or modification with cationic groups (e.g. 4-amino-4-deoxy-L-arabinose (L-Ara4N), or phosphoethanolamine), but also hydroxylation of acyl-groups of lipid A. Here, we study the in vitro evolutionary trajectories towards colistin resistance in clinical K. pneumoniae complex strains (three K. pneumoniae sensu stricto strains and one K. variicola subsp. variicola strain) and their impact on fitness and virulence characteristics. Through population sequencing during the in vitro evolution experiment, we found that resistance develops through a combination of single nucleotide polymorphisms (SNPs), insertion and deletions (indels), and the integration of insertion sequence (IS) elements, affecting genes associated with LPS biosynthesis and modification, and capsule structures. The development of colistin resistance decreased the maximum growth rate of one K. pneumoniae sensu stricto strain, but not in the other three K. pneumoniae sensu lato strains. Colistin-resistant strains had lipid A modified through hydroxylation, palmitoylation, and L-Ara4N addition. Colistin-resistant K. pneumoniae sensu stricto strains exhibited cross-resistance to LL-37, in contrast to the K. variicola subsp. variicola strain that did not change in susceptibility to LL-37. Virulence, as determined in a Caenorhabditis elegans survival assay, was higher in two colistin-resistant strains. Our study suggests that nosocomial K. pneumoniae complex strains can rapidly develop colistin resistance de novo through diverse evolutionary trajectories upon exposure to colistin. This effectively shortens the lifespan of this last-resort antibiotic for the treatment of infections with multidrug-resistant Klebsiella. Author summaryBacteria that frequently cause infections in hospitalised patients are becoming increasingly resistant to antibiotics. Colistin is a positively charged antibiotic that is used for the treatment of infections with multidrug-resistant Gram-negative bacteria. Colistin acts by specifically interacting with the negatively charged LPS molecule in the outer membrane of Gram-negative bacteria. Colistin resistance is mostly mediated through modification of LPS to reduce its negative charge. Here, we use a laboratory evolution experiment to show that strains belonging to the Klebsiella pneumoniae complex, a common cause of multidrug-resistant hospital-acquired infections, can rapidly accumulate mutations that reduce the negative charge of LPS without an appreciable loss of fitness. Colistin resistance can lead to cross-resistance to an antimicrobial peptide of the human innate immune system, but can increase susceptibility to serum, and virulence in a nematode model. These findings show that extensively resistant K. pneumoniae complex strains may rapidly develop resistance to the last-resort antibiotic colistin via different evolutionary trajectories, while retaining their ability to cause infections.

microbiology↗

Complex genetic network underlying the convergent of Rett Syndrome like (RTT-L) phenotype in neurodevelopmental disorders

Mutations of the X-linked gene encoding methyl-CpG-binding protein 2 (MECP2) cause classical forms of Rett syndrome (RTT) in girls. Patients with features of classical Rett syndrome, but do not fulfill all the diagnostic criteria (e.g. absence of a MECP2 mutation), are defined as atypical Rett syndrome. Genes encoding for cyclin-dependent kinase-like 5 (CDKL5) and forkhead box G1 (FOXG1) are more commonly found in patients with atypical Rett syndrome. Nevertheless, a subset of patients who are recognized to have an overlapping phenotype with RTT but are lacking a mutation in a gene that causes typical or atypical RTT are described as having Rett syndrome like phenotype (RTT-L). Whole Exome Sequencing (WES) of 8 RTT-L patients from our cohort revealed mutations in the genes GABRG2, GRIN1, ATP1A2, KCNQ2, KCNB1, TCF4, SEMA6B, and GRIN2A, which are seemingly unrelated to Rett syndrome genes. We hypothesized that the phenotypic overlap in RTT and RTT-L is caused by mutations in genes that affect common cellular pathways critical for normal brain development and function. We annotated the list of genes identified causing RTT-L from peer-reviewed articles and performed a protein-protein interaction (PPI) network analysis. We also investigated their interaction with RTT (typical or atypical) genes such as MECP2, CDKL5, NTNG1, and FOXG1. We found that the RTT-L-causing genes were enriched in the biological pathways such as circadian entrainment, the CREB pathway, and RET signaling, and neuronal processes like ion transport, synaptic transmission, and transcription. We conclude that genes that significantly interact with the PPI network established by RTT genes cause RTT-L, explaining the considerable feature overlap between genes that are indicated for RTT-L and RTT.

genomics↗

BET inhibition induces an anti-apoptotic adaptive response and therapeutic vulnerability to MCL1 inhibitors in breast cancer

The development of effective targeted therapies for the treatment of basal-like breast cancers remains challenging. Here, we demonstrate that BET inhibition induces a multi-faceted adaptive response program leading to MCL1 protein-driven evasion of apoptosis in breast cancers. Consequently, co-targeting MCL1 and BET is highly synergistic in in vitro and in vivo breast cancer models. Drug response and genomics analyses revealed that MCL1 copy number alterations, including low-level gains, are selectively enriched in basal-like breast cancers and associated with effective BET and MCL1 co-targeting. The mechanism of adaptive response to BET inhibition involves upregulation of critical lipid metabolism enzymes including the rate-limiting enzyme stearoyl-CoA desaturase (SCD). Changes in the lipid metabolism are associated with increases in cell motility and membrane fluidity as well as transitions in cell morphology and adhesion. The structural changes in the cell membrane leads to re-localization and activation of HER2/EGFR which can be interdicted by inhibiting SCD activity. Active HER2/EGFR, in turn, induces accumulation of MCL1 protein and therapeutic vulnerability to MCL1 inhibitors. The BET protein, lipid metabolism and receptor tyrosine kinase activation cascade is observed in patient cohorts of basal-like and HER2-amplified breast cancers. The high frequency of MCL1 chromosomal amplifications (>30%) and gains (>50%) in basal-like breast cancers suggests that BET and MCL1 co-inhibition may have therapeutic utility in this aggressive subtype.

cancer biology↗