Comprehensive characteristics of somatic mutations in the normal tissues of patients with cancer and existence of somatic mutant clones linked to cancer development

Mutational Analysis of Bile Cell-Free DNA in Primary Sclerosing Cholangitis: A Pilot Study

BACKGROUND

Primary sclerosing cholangitis (PSC) is a chronic liver disease characterised by inflammation and fibrosis of the bile ducts, conferring an increased risk of cholangiocarcinoma (CCA). However, detecting CCA early in PSC patients remains challenging due to the limited sensitivity of conventional diagnostic methods, including imaging or bile duct brush cytology during endoscopic retrograde cholangiopancreatography (ERCP). This study aims to evaluate the potential of bile cell-free DNA (cfDNA) mutational analysis, termed the Bilemut assay, as a tool for CCA detection in PSC patients.

METHODS

Sixty-three PSC patients undergoing ERCP due to biliary strictures were prospectively recruited. Bile samples were collected, and cfDNA was extracted and analysed using the Oncomine Pan-Cancer Cell-Free assay. Twenty healthy liver donors were included for comparison. Samples with a mutant allele frequency (MAF) ≥ 0.1% were considered positive. Correlations between mutational status and clinical characteristics were assessed.

RESULTS

cfDNA mutational analysis was successful in all bile samples. Mutations predominantly in KRAS, GNAS, and TP53 were detected in 36.5% (23/63) of PSC patients, compared to 10% (2/20) of healthy donors (p = 0.0269). The clinical characteristics of Bilemut-positive and -negative patients were comparable, though there was a trend towards a lower prevalence of inflammatory bowel disease in the Bilemut-positive group. Among PSC patients diagnosed with CCA during follow-up, 75% were Bilemut-positive, suggesting an association between mutational status and malignancy risk.

CONCLUSIONS

Mutational analysis of cfDNA obtained from bile collected from PSC patients undergoing ERCP is feasible. Implementing the Bilemut assay may help identify patients needing closer surveillance and further imaging studies.

Bioinformatics insights into the role of GFPT1 in breast invasive carcinoma: implications for tumor prognosis, immune modulation, and therapeutic applications

Background

Metabolic reprogramming is a hallmark of cancer, including alterations in the hexosamine biosynthesis pathway (HBP). Glutamine-fructose-6-phosphate transaminase 1 (GFPT1) is the key regulatory enzyme in the HBP; however, its role in invasive breast carcinoma remains underexplored.

Methods

This study utilized integrated data from The Cancer Genome Atlas (TCGA) to assess GFPT1 expression in breast cancer (BRCA) patients. Functional enrichment and mutational landscape analyses were performed, along with chemosensitivity predictions. In vitro experiments were conducted by silencing GFPT1 in malignant breast epithelial cells to evaluate changes in proliferation, migration, and apoptosis.

Results

Elevated GFPT1 expression was linked to advanced-stage breast cancer and identified as an independent prognostic marker for overall survival (OS). High GFPT1 levels were associated with increased cytoplasmic translation, activation of oncogenic pathways, and infiltration of M2 macrophages. The GFPT1-High group also showed a higher mutational burden, with frequent TP53 mutations. Chemosensitivity analysis revealed increased IC50 values for chemotherapy drugs in this group. GFPT1 silencing led to reduced cell proliferation and migration, along with enhanced apoptosis.

Conclusion

These findings indicate that GFPT1 is a novel prognostic biomarker and a predictive indicator of chemotherapy response in invasive breast carcinoma. GFPT1 influences mRNA translation, cell cycle regulation, and M2 macrophage infiltration, thereby promoting cancer cell proliferation and metastasis.

Commonalities and differences in the mutational signature and somatic driver mutation landscape across solid and hollow viscus organs

Advances in sequencing have revealed a highly variegated landscape of mutational signatures and somatic driver mutations in a range of normal tissues. Normal tissues accumulate mutations at varying rates ranging from 11 per cell per year in the liver, to 1879 per cell per year in the bladder. In addition, some normal tissues are also comprised of a large proportion of cells which possess driver mutations while appearing phenotypically normal, as in the oesophagus where a majority of cells harbour driver mutations. Individual tissue proliferation and mutation rate, unique mutagenic stimuli, and local tissue architecture contribute to this highly variegated landscape which confounds the functional characterization of driver mutations found in normal tissue. In particular, our understanding of the relationship between normal tissue somatic mutations and tumour initiation or future cancer risk remains poor. Here, we describe the mutational signatures and somatic driver mutations in solid and hollow viscus organs, highlighting unique characteristics in a tissue-specific manner, while simultaneously seeking to describe commonalities which can bring forward a basic unified theory on the role of these driver mutations in tumour initiation. We discuss novel findings which can be used to inform future research in this field.

Shared genetic and epigenetic changes link aging and cancer

Aging is a universal biological process that increases the risk of multiple diseases including cancer. Growing evidence shows that alterations in the genome and epigenome, driven by similar mechanisms, are found in both aged cells and cancer cells. In this review, we detail the genetic and epigenetic changes associated with normal aging and the mechanisms responsible for these changes. By highlighting genetic and epigenetic alterations in the context of tumorigenesis, cancer progression, and the aging tumor microenvironment, we examine the possible impacts of the normal aging process on malignant transformation. Finally, we examine the implications of age-related genetic and epigenetic alterations in both tumors and patients for the treatment of cancer.

Cancer Neoantigens: Challenges and Future Directions for Prediction, Prioritization, and Validation

Prioritization of immunogenic neoantigens is key to enhancing cancer immunotherapy through the development of personalized vaccines, adoptive T cell therapy, and the prediction of response to immune checkpoint inhibition. Neoantigens are tumor-specific proteins that allow the immune system to recognize and destroy a tumor. Cancer immunotherapies, such as personalized cancer vaccines, adoptive T cell therapy, and immune checkpoint inhibition, rely on an understanding of the patient-specific neoantigen profile in order to guide personalized therapeutic strategies. Genomic approaches to predicting and prioritizing immunogenic neoantigens are rapidly expanding, raising new opportunities to advance these tools and enhance their clinical relevance. Predicting neoantigens requires acquisition of high-quality samples and sequencing data, followed by variant calling and variant annotation. Subsequently, prioritizing which of these neoantigens may elicit a tumor-specific immune response requires application and integration of tools to predict the expression, processing, binding, and recognition potentials of the neoantigen. Finally, improvement of the computational tools is held in constant tension with the availability of datasets with validated immunogenic neoantigens. The goal of this review article is to summarize the current knowledge and limitations in neoantigen prediction, prioritization, and validation and propose future directions that will improve personalized cancer treatment.

Impact of a Single Nucleotide Polymorphism on the 3D Protein Structure and Ubiquitination Activity of E3 Ubiquitin Ligase Arkadia

Single nucleotide polymorphisms (SNPs) are genetic variations which can play a vital role in the study of human health. SNP studies are often used to identify point mutations that are associated with diseases. Arkadia (RNF111) is an E3 ubiquitin ligase that enhances transforming growth factor-beta (TGF-β) signaling by targeting negative regulators for degradation. Dysregulation of the TGF-β pathway is implicated in cancer because it exhibits tumor suppressive activity in normal cells while in tumor cells it promotes invasiveness and metastasis. Τhe SNP CGT > TGT generated an amino-acid (aa) substitution of Arginine 957 to Cysteine on the enzymatic RING domain of Arkadia. This was more prevalent in a tumor than in a normal tissue sample of a patient with colorectal cancer. This prompted us to investigate the effect of this mutation in the structure and activity of Arkadia RING. We used nuclear magnetic resonance (NMR) to analyze at an atomic-level the structural and dynamic properties of the R957C Arkadia RING domain, while ubiquitination and luciferase assays provided information about its enzymatic functionality. Our study showed that the R957C mutation changed the electrostatic properties of the RING domain however, without significant effects on the structure of its core region. However, the functional studies revealed that the R957C Arkadia exhibits significantly increased enzymatic activity supporting literature data that Arkadia within tumor cells promotes aggressive and metastatic behavior.

Immuno-genomic classification of colorectal cancer organoids reveals cancer cells with intrinsic immunogenic properties associated with patient survival

Background

The intrinsic immuno-ge7nomic characteristics of colorectal cancer cells that affect tumor biology and shape the tumor immune microenvironment (TIM) are unclear.

Methods

We developed a patient-derived colorectal cancer organoid (CCO) model and performed pairwise analysis of 87 CCOs and their matched primary tumors. The TIM type of the primary tumor was classified as immuno-active, immuno-exhausted, or immuno-desert.

Results

The gene expression profiles, signaling pathways, major oncogenic mutations, and histology of the CCOs recapitulated those of the primary tumors, but not the TIM of primary tumors. Two distinct intrinsic molecular subgroups of highly proliferative and mesenchymal phenotypes with clinical significance were identified in CCOs with various cancer signaling pathways. CCOs showed variable expression of cancer-specific immune-related genes such as those encoding HLA-I and HLA-II, and molecules involved in immune checkpoint activation/inhibition. Among these genes, the expression of HLA-II in CCOs was associated with favorable patient survival. K-means clustering analysis based on HLA-II expression in CCOs revealed a subgroup of patients, in whom cancer cells exhibited Intrinsically Immunogenic Properties (Ca-IIP), and were characterized by high expression of signatures associated with HLA-I, HLA-II, antigen presentation, and immune stimulation. Patients with the Ca-IIP phenotype had an excellent prognosis, irrespective of age, disease stage, intrinsic molecular type, or TIM status. Ca-IIP was negatively correlated with intrinsic E2F/MYC signaling. Analysis of the correlation between CCO immuno-genotype and TIM phenotype revealed that the TIM phenotype was associated with microsatellite instability, Wnt/β-catenin signaling, APC/KRAS mutations, and the unfolded protein response pathway linked to the FBXW7 mutation in cancer cells. However, Ca-IIP was not associated with the TIM phenotype.

Conclusions

We identified a Ca-IIP phenotype from a large set of CCOs. Our findings may provide an unprecedented opportunity to develop new strategies for optimal patient stratification in this era of immunotherapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-02034-1.

Characterization of early postzygotic somatic mutations through multi-organ analysis

Mosaicisms caused by postzygotic mutational events are of increasing interest because of their potential association with various human diseases. Postzygotic somatic mutations have not been well characterized however in terms of their developmental lineage in humans. We conducted whole-genome sequencing (WGS) and targeted deep sequencing in 15 organs across three developmental lineages from a single male fetus with polycystic kidney disease (PKD) of 21 weeks gestational age. This fetus had no detectable neurological abnormalities at autopsy but germline mutations in the PKHD1 gene were identified that may have been associated with the PKD. Eight early embryonic mosaic variants with no alteration of protein function were detected. These variants were thought to have occurred at the two or four cell stages after fertilization with a mutational pattern involving frequent C>T and T>C transitions. In our current analyses, no tendency toward organ-specific mutation occurrences was found as the eight variants were detected in all 15 organs. However different allele fractions of these variants were found in different organs, suggesting a tissue-specific asymmetric growth of cells that reflected the developmental germ layer of each organ. This indicated that somatic mutation occurrences, even in early embryogenesis, can affect specific organ development or disease. Our current analyses demonstrate that multi-organ analysis is helpful for understanding genomic mosaicism. Our results also provide insights into the biological role of mosaicism in embryonic development and disease.