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Cytotoxin and pyrogenic toxin superantigen gene profiles of Staphylococcus aureus associated with subclinical mastitis in dairy cows and relationships with macrorestriction genomic profiles.

A set of 84 Staphylococcus aureus isolates collected from the milk of cows with subclinical mastitis in Asturias (a cattle region of Spain) and six control strains were tested for sequences of genes encoding hemolysins (hla, hlb, hld, hlg, and hlg-2), leukotoxins (lukPV, lukM, and lukED), toxic shock syndrome toxin (tst), and enterotoxins (sea to see, seg to ser, and seu) by conventional and multiplex PCR. It was found that 84, 83, 11, and 39 isolates carried some type of hl, luk, tst, or se gene, respectively, which were arranged in 14 exotoxin genotypes. All of the isolates were negative for lukPV, hlg, sea, sed, see, sej, sek, sep, seq, and ser. Two gene groupings could be related with pathogenicity islands-[lukED, seg, sei, sem, sen, seo +/- seu] with Sabeta-1 and [tst, sec, sel] with SaPIbov, present in 45 and 13.1% of the isolates, respectively-while 11.9% of them carried both islands. Only one contained seb (together with upsilonSabeta-1), and another contained seh (together with lukED). The isolates were also analyzed by pulsed-field gel electrophoresis performed with SmaI. Thirty-nine SmaI profiles (similarity coefficient [S] = 0.94 to 0.21) were differentiated; 12, 1, and 10 of these, respectively, were generated by isolates presumptively carrying Sabeta-1, SaPIbov, or both. Five SmaI profiles (S > or = 0.8) formed a cluster, which contained 20 and 10 isolates carrying one (upsilonSabeta-1) or both islands. These data show the high frequency of genes encoding cytotoxins and pyrogenic toxin superantigens, their relationship with pathogenicity islands, and their distribution among a diversity of genetic types of S. aureus related to subclinical mastitis.

Animals↗

Serial CSF CA19-9 monitoring and CSF genomic profiling in ERBB2-mutant lung adenocarcinoma with leptomeningeal metastasis: a case report.

Leptomeningeal metastasis (LM) from ERBB2-mutant lung adenocarcinoma is difficult to treat and monitor because systemic disease and leptomeningeal disease may evolve discordantly. Evidence regarding cerebrospinal fluid (CSF) genomic profiling and serial CSF tumor marker monitoring in ERBB2-mutant non-small cell lung cancer with LM remains limited. We report a 48-year-old woman initially diagnosed with stage IB mucinous lung adenocarcinoma harboring an ERBB2 exon 20 p.G776delinsVC mutation. After surgery and adjuvant chemotherapy, she developed nodal recurrence and later presented with lower back pain and lower-limb numbness. LM was clinically diagnosed based on neurological symptoms, magnetic resonance imaging and CSF cytopathology. She received craniospinal irradiation, systemic therapy and subsequent intrathecal treatment. At month 33, CSF CA19-9 was markedly elevated despite no clear radiographic systemic progression. CSF next-generation sequencing(NGS) detected the same ERBB2 exon 20 p.G776delinsVC mutation as the primary lung tumor, with a higher variant allele fraction in CSF than in lung tissue.The patient subsequently received trastuzumab deruxtecan and sequential intrathecal therapy with pemetrexed, etoposide, cytarabine and pemetrexed rechallenge. Intrathecal treatment was adjusted according to serial CSF CA19-9 levels, neurological status, imaging findings, systemic disease activity and treatment-related toxicities. CSF CA19-9 was not used as a stand-alone criterion for progression or treatment modification.At the latest follow-up, she remained alive more than 36 months after the clinical diagnosis of LM. This case suggests that CSF NGS and serial CSF CA19-9 may provide further insights into disease activity within the integrated assessment of systemic and leptomeningeal disease. Their clinical applicability is still under investigation and necessitates future validation.

CA19-9↗

Genomic Profiling of Anophthalmia/Microphthalmia-Associated CNVs Reveals Complex Genotype-Phenotype Correlations and Incomplete Penetrance.

BACKGROUND: Anophthalmia/microphthalmia (A/M) is a severe congenital ocular malformation characterized by the complete absence or small size of the eye bulb. Interpreting copy number variations (CNVs) in A/M is challenged by variable genotype-phenotype correlations and reduced penetrance. This study investigated the genetic etiology of A/M-associated CNVs. METHODS: Genomic profiling was performed on four unrelated families presenting with ocular anomalies or harboring A/M-susceptible CNVs. Variants were evaluated by integrating American College of Medical Genetics and Genomics (ACMG) guidelines with clinical phenotypes and familial segregation. RESULTS: An inherited 8.13 Mb deletion (8p23.3p23.1) in Patient 1 was excluded due to genotype-phenotype mismatch. Patients 2 and 3 harbored de novo pathogenic deletions involving OTX2 (14q22.3) and SOX2 (3q26.33), causing typical A/M. Case 4 revealed a 14q22.2q23.1 deletion encompassing OTX2 in a fetus and mother without ocular anomalies, consistent with the incomplete penetrance of OTX2-related microphthalmia. Thus, CNV-induced haploinsufficiency causes A/M with high phenotypic variability. CONCLUSION: Accurate CNV interpretation requires robust genotype-phenotype correlation and careful assessment of incomplete penetrance to prevent diagnostic pitfalls and improve genetic counseling.

Female↗

Genome profiling: a realistic solution for genotype-based identification of species.

Species identification is the basis of Biology and has been carried out based on phenotype. Although some genes, such as that for 16S rRNA, have been used for species confirmation, identification of species based only on genotype has never been done before, although recent whole genome sequencing studies have demonstrated it to be possible in principle. However, it is evidently unrealistic for routine experiments of species identification. This paper clarifies that a very limited amount of information derived from a genome sequence is sufficient for identifying the species. It also proves that Genome Profiling [Nishigaki, K., Amano, N., and Takasawa, T. (1991) Chem. Lett. 1097-1100], TGGE analysis of random PCR products, can not only fulfill such requirements, but also serve as a universal method to analyze species. Thus, this compact technology can be used in many fields of biology, especially in microbe-related disciplines such as microbial ecology and epidemiology where exact knowledge about all members of a population is essential but previously difficult to obtain. This is the first demonstration that genotype-based identification of species is possible using a simple and uniform protocol for all organisms.

Animals↗

High-resolution genomic profiles of human lung cancer.

Lung cancer is the leading cause of cancer mortality worldwide, yet there exists a limited view of the genetic lesions driving this disease. In this study, an integrated high-resolution survey of regional amplifications and deletions, coupled with gene-expression profiling of non-small-cell lung cancer subtypes, adenocarcinoma and squamous-cell carcinoma (SCC), identified 93 focal copy-number alterations, of which 21 span <0.5 megabases and contain a median of five genes. Whereas all known lung cancer genes/loci are contained in the dataset, most of these recurrent copy-number alterations are previously uncharacterized and include high-amplitude amplifications and homozygous deletions. Notably, despite their distinct histopathological phenotypes, adenocarcinoma and SCC genomic profiles showed a nearly complete overlap, with only one clear SCC-specific amplicon. Among the few genes residing within this amplicon and showing consistent overexpression in SCC is p63, a known regulator of squamous-cell differentiation. Furthermore, intersection with the published pancreatic cancer comparative genomic hybridization dataset yielded, among others, two focal amplicons on 8p12 and 20q11 common to both cancer types. Integrated DNA-RNA analyses identified WHSC1L1 and TPX2 as two candidates likely targeted for amplification in both pancreatic ductal adenocarcinoma and non-small-cell lung cancer.

Carcinoma, Non-Small-Cell Lung↗

Genome profiling of melanocytic tumors using multiplex ligation-dependent probe amplification (MLPA): Its usefulness as an adjunctive diagnostic tool for melanocytic tumors.

BACKGROUND: The histopathology of melanocytic tumors sometimes presents diagnostic problems. Applicable parameters other than routine pathology are needed. OBJECTIVE: We assessed the feasibility of multiplex ligation-dependent probe amplification (MLPA), a novel PCR-based genome profiling method, in the classification of melanocytic tumors. METHOD: We extracted DNA from paraffin-embedded tissue sections of 24 primary melanomas, 14 Spitz nevi and 17 common melanocytic nevi. We analyzed the copy number gains or losses of a total of 76 genes spanning almost all chromosome arms using commercially available MLPA kits. RESULTS: Although four melanocytic nevi and three Spitz nevi did not yield sufficient DNA for reliable analysis due to small tumor size, the MLPA analysis was feasible and applicable to the remaining 88% of samples. We found multiple genetic aberrations in primary melanomas. The total number of aberrations in each tumor ranged from 1 to 32 (average, 12.04). All but two melanomas showed aberrations at more than three genetic loci. Seventeen (70.8%) of the 24 melanomas showed a copy number loss of either the CDKN2A or CDKN2B gene on chromosome 9p21. All the Spitz nevi and 7 (50%) of 14 common melanocytic nevi had copy number changes at one or two gene loci (average, 1.04). The receiver operator characteristic curve analysis showed that the threshold value of copy number aberrations corresponding to 98% specificity for melanoma was 2.42 and the sensitivity using this threshold value was 92.5%. CONCLUSIONS: MLPA could be used as an adjunctive diagnostic tool for melanocytic tumors.

Cell Cycle Proteins↗

Inflammatory malignant fibrous histiocytomas and dedifferentiated liposarcomas: histological review, genomic profile, and MDM2 and CDK4 status favour a single entity.

Inflammatory malignant fibrous histiocytoma (inflammatory MFH) is a very rare tumour that occurs most often in the retroperitoneum. So far, it has been considered to be a special subtype of MFH. As it is now widely accepted that most retroperitoneal pleomorphic MFHs are dedifferentiated liposarcomas, the present study compared histological features, genomic profile (CGH analysis), and MDM2 and CDK4 status (immunohistochemistry, FISH, and quantitative PCR) in inflammatory MFHs from 12 patients and dedifferentiated liposarcomas that had an inflammatory MFH component from eight patients. Metaphase cytogenetic and FISH analyses were also performed on one inflammatory MFH. Histological review showed areas of well-differentiated liposarcoma in nine inflammatory MFHs. CGH analysis showed 12q13-15 amplification or gain in six of seven inflammatory MFHs and in seven of seven dedifferentiated liposarcomas. Immunohistochemistry showed positivity of tumour cells for MDM2 in every tumour in both groups and for CDK4 in ten and seven inflammatory MFHs and dedifferentiated liposarcomas, respectively. Metaphase cytogenetic and FISH analysis performed on one inflammatory MFH showed the presence of a supernumerary large marker chromosome and ring chromosome with high-level amplification of both MDM2 and CDK4 genes. FISH analysis on paraffin wax-embedded sections showed amplifications of MDM2 and CDK4 in seven of seven inflammatory MFHs and in seven of seven dedifferentiated liposarcomas. Quantitative PCR showed amplification of MDM2 in six and of CDK4 in seven of nine inflammatory MFHs. In conclusion, this study strongly suggests that most so-called inflammatory MFHs are dedifferentiated liposarcomas.

Adult↗

Comprehensive Clinicopathologic, Immunohistochemical, and Genomic Profiling of Sporadic Ampullary Somatostatin-producing D-cell Neuroendocrine Tumors Identifies Recurrent HRAS Hotspot Mutations.

Ampullary somatostatin-producing D-cell neuroendocrine tumors are rare neoplasms that may be associated with type 1 neurofibromatosis. The molecular features of sporadic ampullary somatostatin-producing D-cell neuroendocrine tumors (SAMSOM-NETs) remain poorly characterized. We performed an integrated morphological, immunohistochemical, and genomic analysis of a multicenter series of SAMSOM-NETs. Eleven cases were included (73% male; median age: 63&#xa0;years). All six patients who underwent lymphadenectomy were staged as pN1, and liver metastases were found in three cases; however, no tumor-related deaths occurred (median follow-up: 104&#xa0;months). Common histologic features that can pose diagnostic challenges in the differential diagnosis with adenocarcinoma included a tubulo-glandular architecture (100%), periodic Acid-Schiff (PAS)-positive intraluminal mucin (73%), MUC1 expression (100%), and carcinoembryonic antigen (45%) expression. All tumors exhibited dot-like cytoplasmic reactivity for cytokeratins (CK) CAM5.2 or CK AE1/AE3, and 82% were CK7-positive. ISL1 and PDX1 were diffusely expressed in all cases, while CDX2 was positive in 54% and ARX showed only focal expression in four tumors. Genomic profiling revealed microsatellite stability and low tumor mutational burden. Alterations in the RAS pathway, including HRAS mutations (4 cases, 36%), a KRAS mutation (1 case), and NF1 alterations (one case), were identified in 54% of cases and in all tumors with liver metastases. Additional molecular findings included a CDK12 splice-site alteration and an NTRK3::PRDM4 fusion. Potentially actionable alterations affecting kinase-related pathways were detected in 64% of tumors. Our findings support SAMSOM-NET as a peculiar neuroendocrine tumor subtype showing distinctive histologic and molecular characteristics with potential diagnostic and therapeutic implications.

Humans↗

Genomic profiling identifies alterations in TGFbeta signaling through loss of TGFbeta receptor expression in human renal cell carcinogenesis and progression.

Renal cell carcinoma (RCC) is a major health issue. Whereas localized disease can be cured surgically, there is no effective therapy for metastatic disease. The development of an effective therapy will require an understanding of the pathways that are important in RCC carcinogenesis and progression. Using genomic profiling of patient-matched tissue, we have identified aberrations in the transforming growth factor beta (TGFbeta) signaling pathway in RCC. We observed loss of type III TGFbeta receptor (TBR3) expression in all RCC samples. This suggests that TBR3 loss is an early event in RCC carcinogenesis and plays a sentinel role in the acquisition of a tumorigenic phenotype. We also observed subsequent loss of type II TGFbeta receptor (TBR2) expression in metastatic RCCs. We propose that loss of TBR3 is necessary for RCC carcinogenesis, and that loss of TBR2 leads to acquisition of a metastatic phenotype. To this end, we have identified a human renal cell carcinoma line (UMRC6) that is representative of localized, nonmetastatic RCC, reflecting a loss of TBR3, but not TBR2 expression. Another cell line, UMRC3, is highly metastatic, having lost TBR3 and TBR2 expression. We demonstrate functional loss of TGFbeta responsiveness in these cell lines as observed through phenotypic and transcriptional responsiveness to exogenous TGFbeta. Restoring TBR2 and TBR3 expression in UMRC3 cells attenuates cell proliferation, completely restores TGFbeta-mediated transcriptional responses, and completely blocks anchorage independent-growth: while restoration of TBR2 partially restores TGFbeta-mediated signaling. Based on these data, we propose that dysregulation in TGFbeta signaling, through stepwise loss in receptor expression, plays a prominent role in RCC carcinogenesis and progression. In addition, these studies unequivocably demonstrate a link between loss of TBR3 and a human disease.

Carcinoma, Renal Cell↗

Common and contrasting genomic profiles among the major human lung cancer subtypes.

Lung cancer is the leading cause of cancer mortality worldwide. With the recent success of molecularly targeted therapies in this disease, a detailed knowledge of the spectrum of genetic lesions in lung cancer represents a critical step in the development of additional effective agents. An integrated high-resolution survey of regional amplifications and deletions and gene expression profiling of non-small-cell lung cancers (NSCLC) identified 93 focal high-confidence copy number alterations (CNAs), with 21 spanning less than 0.5 Mb with a median of five genes. Most CNAs were novel and included high-amplitude amplification and homozygous deletion events. Pathogenic relevance of these genomic alterations was further reinforced by their recurrence and overlap with focal alterations of other tumor types. Additionally, the comparison of the genomic profiles of the two major subtypes of NSCLC, adenocarcinoma (AC) and squamous cell carcinoma (SCC), showed an almost complete overlap with the exception of one amplified region on chromosome 3, specific for SCC. Among the few genes overexpressed within this amplicon was p63, a known regulator of squamous cell differentiation. These findings suggest that the AC and SCC subtypes may arise from a common cell of origin and they are driven to their distinct phenotypic end points by altered expression of a limited number of key genes such as p63.

Adenocarcinoma↗

Unusual relapse dynamics in EGFR-mutated lung adenocarcinoma uncovered by genomic profiling: Insights from a case report.

Synchronous or metachronous multiple NSCLCs challenge clinical practice, particularly in distinguishing multiple separate primary lung cancers (SPLC) from intrapulmonary metastasis (IPM) for accurate staging and management. Here, we present a unique case of three resected lung adenocarcinomas (LUAD) from a single patient collected at different time points, all harboring the same EGFR p.L858R somatic driver mutation but exhibiting distinct clonal trajectories. Whole exome sequencing (WES) analysis revealed that the first tumor was an independent primary tumor, while the latter two tumors were clonally related. Our findings highlight the complexity of tumor progression and provide insights into clonal heterogeneity. This report underscores the importance of genomic profiling for discriminating SPLC from IPM and emphasizes that the detection of a single shared driver mutation is not sufficient to prove metastasis.

Humans↗

Genomic profiling associated with recurrence in patients with rectal cancer treated with chemoradiation.

PURPOSE: Stage II and III adenocarcinoma of the rectum has an overall 5-year survival rate of approximately 50%, and tumor recurrence remains a major problem despite an improvement in local control through chemotherapy and radiation. The efficacy of chemoradiation therapy may be significantly compromised as a result of interindividual variations in clinical response and host toxicity. Therefore, it is imperative to identify those patients who will benefit from chemoradiation therapy and those who will develop recurrent disease. In this study, we tested whether a specific pattern of 21 polymorphisms in 18 genes involved in the critical pathways of cancer progression (i.e., drug metabolism, tumor microenvironment, cell cycle regulation, and DNA repair) will predict the risk of tumor recurrence in rectal cancer patients treated with chemoradiation. PATIENTS AND METHODS: A total of 90 patients with Stage II or III rectal cancer treated with chemoradiation were genotyped using polymerase chain reaction (PCR)-based techniques for 21 polymorphisms. RESULTS: A polymorphism in interleukin (IL)-8 was individually associated with risk of recurrence. Classification and regression tree analysis of all polymorphisms and clinical variables developed a risk tree including the following variables: node status, IL-8, intracellular adhesion molecule-1, transforming growth factor-beta, and fibroblast growth factor receptor 4. CONCLUSION: Genomic profiling may help to identify patients who are at high risk for developing tumor recurrence, and those who are more likely to benefit from chemoradiation therapy. A larger prospective study is needed to validate these preliminary data using germline polymorphisms on tumor recurrences in rectal cancer patients treated with chemoradiation.

Antineoplastic Agents↗

Genomic profiling by circulating tumor DNA in patients with hormone receptor-positive/HER2-negative advanced breast cancer: Prevalence of actionable mutations across treatment lines.

INTRODUCTION: Plasma next-generation sequencing (NGS) is endorsed by ESMO as an alternative to tissue testing in advanced hormone receptor-positive, HER2-negative metastatic breast cancer (HR+/HER2- mBC), particularly after progression on endocrine therapy plus CDK4/6 inhibitors. However, prospective real-world data across distinct therapeutic contexts remain limited. PATIENTS AND METHODS: In this prospective observational study conducted within a nationwide cancer network in Brazil, centralized plasma NGS, and tissue NGS when available, was performed in two independent cohorts: prior to initiation of first-line endocrine therapy in the metastatic setting (Cohort 1) and at progression on endocrine therapy plus a CDK4/6 inhibitor (Cohort 2). The primary objective was to evaluate plasma-detected ESR1 mutation prevalence across these therapeutic contexts, and secondarily to assess other actionable drivers detected by plasma or tissue NGS. RESULTS: Among 86 collected plasma samples, 72 (84%) had evaluable NGS results (Cohort 1, n = 37; Cohort 2, n = 35). ESR1 mutations were identified in 18.9% of patients in Cohort 1 and 40.0% in Cohort 2, mostly at low variant allele fractions (<0.5%), corresponding to an absolute prevalence difference of 21.1 percentage points (95% CI, -0.2 to 40.3; P value=0.07). When considering any actionable alteration detected by plasma, including ESR1, PIK3CA, AKT1, PTEN, BRCA1, BRCA2, and ERBB2, prevalences were 43.2% and 68.6%, respectively (P value=0.04). Only four patients had ESR1 mutations identified in tissue, three in metastatic samples. Plasma-tissue concordance was higher for PIK3CA mutations (85.1%). CONCLUSION: Plasma NGS identified clinically meaningful ESR1 mutation rates across both contexts, supporting guideline-endorsed plasma-based genomic profiling in HR+/HER2- mBC.

CDK4/6 inhibitors↗

Chemical genomic profiling of biological networks using graph theory and combinations of small molecule perturbations.

Genome-wide measurements of multiple experimental samples yield rich fingerprints for comparison and interpretation. Here, a two-dimensional matrix of the cellular effects of all possible pairwise combinations of 24 small molecules, each with a different structure and bioactivity, was used to profile otherwise isogenic deletion strains of the yeast Saccharomyces cerevisiae. Using principles from graph theory, we derived a discrete model of the data for each strain by encoding the information in the form of a binary adjacency matrix. This matrix was used to construct a graph composed of nodes representing small molecules and edges connecting combinations that inhibited cell cycle progression. Computation of a set of graph theoretic descriptors for each chemical genetic network provided a topological fingerprint that showed genotype-dependent fluctuations. Because the structure of the genetic network determines the structure of the chemical genetic network, multidimensional chemical genomic profiling can be used for the characterization of perturbations in biological networks or the networks themselves. This application of small molecules could be useful for discerning the molecular basis of highly complex biological phenotypes, including those involved in the susceptibility to or etiology of human disease.

Computer Graphics↗

Endoscopic ultrasound-guided biopsy of left and right adrenal metastases enabling pathological diagnosis and genomic profiling after nondiagnostic conventional biopsies: two case reports.

Obtaining adequate tissue for histologic diagnoses and genomic testing can be challenging in metastatic lung cancer, particularly when conventional biopsy approaches are nondiagnostic. The study reports an effective salvage strategy using endoscopic ultrasound (EUS)-guided adrenal tissue acquisition in two cases. A 66-year-old woman (case 1) developed recurrent lung adenocarcinoma with progressive metastases to the left adrenal, liver, and lungs following multiple lines of systemic therapy. A percutaneous biopsy of a suspected liver metastasis proved nondiagnostic. Subsequently, transgastric EUS-guided biopsy was performed, which confirmed metastatic adenocarcinoma originating in the lung. Oncomine-based genomic testing detected a human epidermal growth factor receptor 2 exon 20 insertion. Trastuzumab deruxtecan was subsequently introduced, resulting in disease stabilization for 6 months. A 75-year-old man (case 2) developed bilateral pulmonary nodules and a right adrenal mass detected on positron emission tomography. Bronchoscopy failed to yield diagnostic tissue. Following careful review of cross-sectional anatomy, EUS-guided biopsy of the right adrenal gland was safely performed via the duodenal bulb, confirming metastatic squamous cell carcinoma and yielding adequate tissue for genomic testing. EUS-guided adrenal biopsy, including transduodenal sampling of the right adrenal gland, may provide tissue for histopathologic and precision oncology testing, facilitating definitive diagnoses.

Adrenal metastasis↗

Genomic profiles in stage I primary non small cell lung cancer using comparative genomic hybridization analysis of cDNA microarrays.

To investigate the genomic aberrations that are involved in lung tumorigenesis and therefore may be developed as biomarkers for lung cancer diagnosis, we characterized the genomic copy number changes associated with individual genes in 14 tumors from patients with primary non small cell lung cancer (NSCLC). Six squamous cell carcinomas (SQCAs) and eight adenocarcinomas (ADCAs) were examined by high-resolution comparative genomic hybridization (CGH) analysis of cDNA microarray. The SQCAs and ADCAs shared common frequency distributions of recurrent genomic gains of 63 genes and losses of 72 genes. Cluster analysis using 57 genes defined the genomic differences between these two major histologic types of NSCLC. Genomic aberrations from a set of 18 genes showed distinct difference of primary ADCAs from their paired normal lung tissues. The genomic copy number of four genes was validated by fluorescence in situ hybridization of 32 primary NSCLC tumors, including those used for cDNA microarray CGH analysis; a strong correlation with cDNA microarray CGH data emerged. The identified genomic aberrations may be involved in the initiation and progression of lung tumorigenesis and, most importantly, may be developed as new biomarkers for the early detection and classification of lung cancer.

Adenocarcinoma↗

Chrom-Sig: de-noising 1D genomic profiles by signal processing methods.

MOTIVATION: Modern genomic research is driven by next-generation sequencing experiments such as ChIP-seq, CUT&Tag, and CUT&RUN that generate coverage files for transcription factor binding, as well as ATAC-seq that yield coverage files for chromatin accessibility. Due to the inherent technical noise present in the experimental protocols, researchers need statistically rigorous and computationally efficient methods to extract true biological signal from a mixture of signal and noise. However, existing approaches are often computationally demanding or require input or spike-in controls. RESULTS: We developed Chrom-Sig, a Python package to quickly de-noise 1D genomic coverage tracks by computing the empirical null distribution without prior assumptions or experimental controls. When tested on 19 ChIP-seq, CUT&RUN, ATAC-seq, and snATAC-seq datasets, Chrom-Sig can effectively decompose the data into signal and noise components. Notably, Chrom-Sig performs de-noising and peak calling in 1-2&#x2009;h using around 20&#xa0;GB of memory. The de-noised signal corroborates with biologically meaningful results: CTCF CUT&RUN data retained a high percentage of peaks overlapping CTCF binding motifs, while ATAC-seq and RNA Polymerase II data were enriched in enhancers and promoters. We envision Chrom-Sig to be a versatile and general tool for current and future genomic technologies. AVAILABILITY AND IMPLEMENTATION: Chrom-Sig is publicly available on GitHub (https://github.com/minjikimlab/chromsig) and Zenodo (doi: 10.5281/zenodo.17488772) under the MIT licence.

Genomics↗

scooby: Modeling multi-modal genomic profiles from DNA sequence at single-cell resolution.

Understanding how regulatory DNA elements shape gene expression across individual cells is a fundamental challenge in genomics. Joint RNA-seq and epigenomic profiling provides opportunities to build unifying models of gene regulation capturing sequence determinants across steps of gene expression. However, current models, developed primarily for bulk omics data, fail to capture the cellular heterogeneity and dynamic processes revealed by single-cell multi-modal technologies. Here, we introduce scooby, the first framework to model scRNA-seq coverage and scATAC-seq insertion profiles along the genome from sequence at single-cell resolution. For this, we leverage the pre-trained multi-omics profile predictor Borzoi as a foundation model, equip it with a cell-specific decoder, and fine-tune its sequence embeddings. Specifically, we condition the decoder on the cell position in a precomputed single-cell embedding resulting in strong generalization capability. Applied to a hematopoiesis dataset, scooby recapitulates cell-specific expression levels of held-out genes, and identifies regulators and their putative target genes through in silico motif deletion. Moreover, accurate variant effect prediction with scooby allows for breaking down bulk eQTL effects into single-cell effects and delineating their impact on chromatin accessibility and gene expression. We anticipate scooby to aid unraveling the complexities of gene regulation at the resolution of individual cells.

Journal Article↗