Selective multiplexed enrichment for the detection and quantitation of low-fraction DNA variants via low-depth sequencing Low-frequency DNA variants can be detected via low-depth multiplexed sequencing after their amplification using polymerase chain reaction and rationally designed 鈥榖locker鈥?oligonucleotides.Tracking the expression of therapeutic protein targets in rare cells by antibody-mediated nanoparticle labelling and magnetic sorting The expression of therapeutic protein targets in circulating tumour cells isolated from blood samples of patients with cancer can be tracked at the single-cell level by antibody-mediated magnetic labelling and microfluidic sorting. Renally clearable gold quantum clusters that are stabilized by the milk metalloprotein alpha-lactalbumin and display multicolour fluorescence aid the detection, resection and treatment of breast cancer in mice.Targeted tumour theranostics in mice via carbon quantum dots structurally mimicking large amino acids Intravenously injected functionalized carbon quantum dots that bind to the large neutral amino acid transporter 1 and that structurally mimic large amino acids selectively accumulate in human tumours in mice, facilitating targeted theranostics.Selective imaging of solid tumours via the calcium-dependent high-affinity binding of a cyclic octapeptide to phosphorylated Annexin A2 A cyclic octapeptide labelled with a near-infrared dye and that binds, with high affinity at high levels of calcium, to phosphorylated protein Annexin A2 in a range of solid tumours, serves as a tumour-selective imaging probe.Validation of the use of a fluorescent PARP1 inhibitor for the detection of oral, oropharyngeal and oesophageal epithelial cancers A fluorescently labelled inhibitor of the DNA repair enzyme poly(ADP鈥搑ibose) polymerase 1 is used to detect epithelial cancers of the upper intestinal tract in animals, in biopsied human tissue and in a human patient.Carbon-coated FeCo nanoparticles as sensitive magnetic-particle-imaging tracers with photothermal and magnetothermal properties FeCo nanoparticles with a graphitic carbon shell decorated with poly(ethylene glycol) have photothermal and magnetothermal properties and are sensitive tracers for magnetic particle imaging, magnetic resonance imaging and photoacoustic imaging.Barcoded DNA nanostructures for the multiplexed profiling of subcellular protein distribution Barcodes based on tetrahedral DNA nanostructures enable the multiplexed profiling of the subcellular expression and distribution of proteins in cells from patient samples.PET imaging of occult tumours by temporal integration of tumour-acidosis signals from pH-sensitive 64Cu-labelled polymers The detection of small tumours with PET is significantly enhanced by temporal integration of the imaging signals, triggered by the acidic milieu of cancers, from pH-sensitive positron-emitting polycationic polymers.A microfluidic assay for the quantification of the metastatic propensity of breast cancer specimens A microfluidic assay predicts the metastatic potential of breast cancer specimens by quantifying the abundance and proliferative index of the migratory cells within them.Ultrasensitive detection of circulating exosomes with a 3D-nanopatterned microfluidic chip A microfluidic chip with self-assembled 3D herringbone nanopatterns detects, with high sensitivity and specificity, tumour-associated exosomes in few-microlitre plasma samples from patients.Low-cost thermophoretic profiling of extracellular-vesicle surface proteins for the early detection and classification of cancers An assay that thermophoretically profiles surface proteins from serum extracellular vesicles labelled with a panel of fluorescent aptamers detects and classifies patients according to cancer type and cancer stage. A point-of-care device that can run on a variety of power inputs enables isothermal nucleic acid quantification for the diagnosis of infectious diseases in resource-limited settings with unreliable electrical power supply.Live-cell phenotypic-biomarker microfluidic assay for the risk stratification of cancer patients via machine learning An assay that uses machine-learning algorithms on phenotypic-biomarker data from live primary cells predicts post-surgical adverse pathology in prostate-cancer and breast cancer tissue samples from patients.Design and clinical validation of a point-of-care device for the diagnosis of lymphoma via contrast-enhanced microholography and machine learning A low-cost point-of-care device that uses contrast-enhanced microholography and deep learning accurately detects aggressive lymphomas in patients referred for aspiration and biopsy of enlarged lymph nodes.An intravascular magnetic wire for the high-throughput retrieval of circulating tumour cells in vivo A magnetic wire for the intravascular recovery of labelled circulating tumour cells improves cell capture in anaesthetized pigs by up to two orders of magnitude with respect to a standard blood draw.Maps of in vivo oxygen pressure with submillimetre resolution and nanomolar sensitivity enabled by Cherenkov-excited luminescence scanned imaging A method that uses thin sheets of X-ray radiation to generate emissions of Cherenkov luminescence can image an oxygen-sensitive molecular probe to map oxygenation in tumours in vivo at submillimetre resolution and nanomolar sensitivity.Profiling of protein鈥損rotein interactions via single-molecule techniques predicts the dependence of cancers on growth-factor receptors The characterization of protein鈥損rotein interactions by combined single-molecule pull-down and single-molecule co-immunoprecipitation assays uncovers, for specific cancers, their dependence on signalling complexes of the human epidermal growth-factor receptor. This Review discusses technology for the isolation and phenotypic profiling of circulating tumour cells from blood for the identification of those with high metastatic potential as well as requirements for clinical applications of the cells.Whole-tissue biopsy phenotyping of three-dimensional tumours reveals patterns of cancer heterogeneity A method that identifies patterns of tumour heterogeneity in intact biopsy samples using 3D light-sheet microscopy stratifies patients by tumour stage.Laser-emission imaging of nuclear biomarkers for high-contrast cancer screening and immunodiagnosis A scanning laser-emission-based microscope enables submicrometre-resolution mapping of nuclear biomarkers and the diagnosis of early-stage lung cancer in tissue samples from patients. A light-sheet microscope images large surgical and biopsy specimens non-destructively over large fields of view in two and three dimensions, with the same level of detail as traditional slide-based histopathology. Nanoscale extracellular vesicles can be efficiently isolated in about 15 minutes, for downstream analyses of nucleic acids and proteins, via spontaneous labelling through a lipid nanoprobe and subsequent magnetic capture of the labelled vesicles. A macromolecular near-infrared probe that successively responds to tumour acidity and hypoxia while amplifying detection sensitivity via signal propagation detects metastatic tumour nodules as small as 1鈥塵m in mice. Functionalized InAs quantum dots emitting in the short-wavelength infrared spectral region enable functional biomedical imaging at unprecedentedly high spatial resolution, deep penetration and fast acquisition speeds. An optimized nanosensor with tumour-penetrating ligands and with peptide substrates that lead to maximal tumour-specific protease cleavage detects sub-5鈥塵m lesions in human epithelial tumour xenografts and in an orthotopic model of ovarian cancer.EBNA1-targeted probe for the imaging and growth inhibition of tumours associated with the Epstein鈥揃arr virus A peptide-based fluorescent inhibitor of the dimerization of an oncoprotein of the Epstein鈥揃arr virus blocks the proliferation of tumours associated with the virus in mice. A carbon nanotube sensor enables real-time optical quantification of hybridization events of microRNA and other oligonucleotides in vivo and in whole urine and serum.Light scattering spectroscopy identifies the malignant potential of pancreatic cysts during endoscopy An optical spectroscopic technique and fibre-optic probe, compatible with clinical ultrasound-guided fine-needle aspiration, accurately distinguishes cancerous, precancerous and benign pancreatic cysts.Nanoplasmonic quantification of tumour-derived extracellular vesicles in plasma microsamples for diagnosis and treatment monitoring A rapid, inexpensive and ultrasensitive assay that uses antibody-conjugated nanoparticle probes on the surface of a sensor chip quantifies tumour-derived extracellular vesicles to detect pancreatic cancer from 1 渭l of blood plasma. Progress in fluorescence-guided systems and contrast agents for real-time intraoperative assistance during tumour-resection operations should benefit patient outcomes. Epithelial cancers of the upper intestinal tract in animals, in biopsied human tissue and in a human patient can be detected via a fluorescently labelled inhibitor of the DNA-repair enzyme poly(ADP-ribose) polymerase 1. An optical-imaging instrument that integrates multispectral imaging for the detection of fluorescence in the first and second near-infrared windows aids the surgical resection of liver tumours in patients. The detection of small tumours with positron emission tomography is significantly enhanced by 64Cu-labelled polycationic polymers sensitive to the acidic pH of tumours. The photothermal and magnetothermal properties of carbon-coated iron cobalt nanoparticles with a polymer shell make them sensitive tracers for in vivo magnetic particle imaging, magnetic resonance imaging and photoacoustic imaging.First-in-human liver-tumour surgery guided by multispectral fluorescence imaging in the visible and near-infrared-I/II windows An optical-imaging instrument that integrates a visible multispectral imaging system with the detection of near-infrared fluorescence in the first and second windows aids the fluorescence-guided surgical resection of liver tumours in patients. The localization of target proteins, at subcellular resolution, in fixed patient-derived tissues can now be achieved via antibodies conjugated with tetrahedral DNA nanostructures self-assembled in situ. An inexpensive assay that uses thermophoresis to concentrate cancer extracellular vesicles bound to aptamers specific for target proteins on the vesicles鈥?surface, can classify cancer patients according to cancer type and stage. A lunchbox-sized device for nucleic acid quantification that can be powered by sunlight, a flame or electricity enables the diagnosis of disease in settings with unreliable power supply. A scalable and fast method for profiling single-molecule protein鈥損rotein interactions predicts the sensitivity of cells to inhibitors of the epidermal growth factor receptor, which is typically overexpressed in cancer. Shaping an X-ray beam as a thin sheet generates Cherenkov emissions that enable molecular sensing at submillimetre resolution and deep into tissue in small animals. Light-sheet microscopy reveals 3D tumour heterogeneity in optically cleared paraffin-embedded tumour samples. Laser light emitted by fluorescently stained human tissue inside a laser cavity can be used to diagnose cancer. A light-sheet microscope offers fast three-dimensional imaging of intact clinical tissue samples over large fields of view. The early detection of cancer demands translatable light-emitting or light-collecting probes with unprecedented levels of sensitivity and specificity. The clinical utility of diagnostic markers extracted from liquid biopsies from cancer patients is hampered by knowledge gaps in biological understanding but can be aided by technological developments. Functionalized quantum dots emitting short-wavelength infrared light enable small-animal imaging with deep penetration, high spatial resolution and fast acquisition speeds. Optical probes that are activated only in the tumour microenvironment dramatically improve the sensitivity of cancer detection. Two approaches for quantifying extracellular vesicles in blood samples facilitate the search for highly specific cancer biomarkers. Pancreatic cysts can be detected via the optical-scatter patterns of these submicroscopic sack-like pockets of tissue. A fluorescent peptide that blocks the dimerization of a protein associated with the Epstein鈥揃arr virus enables the imaging and growth inhibition of tumours attributed to the pathogen.