bims-tumhet Biomed News
on Tumor Heterogeneity
Issue of 2024–05–19
eight papers selected by
Sergio Marchini, Humanitas Research



  1. Nat Commun. 2024 May 14. 15(1): 4067
      The complexity of the tumor microenvironment poses significant challenges in cancer therapy. Here, to comprehensively investigate the tumor-normal ecosystems, we perform an integrative analysis of 4.9 million single-cell transcriptomes from 1070 tumor and 493 normal samples in combination with pan-cancer 137 spatial transcriptomics, 8887 TCGA, and 1261 checkpoint inhibitor-treated bulk tumors. We define a myriad of cell states constituting the tumor-normal ecosystems and also identify hallmark gene signatures across different cell types and organs. Our atlas characterizes distinctions between inflammatory fibroblasts marked by AKR1C1 or WNT5A in terms of cellular interactions and spatial co-localization patterns. Co-occurrence analysis reveals interferon-enriched community states including tertiary lymphoid structure (TLS) components, which exhibit differential rewiring between tumor, adjacent normal, and healthy normal tissues. The favorable response of interferon-enriched community states to immunotherapy is validated using immunotherapy-treated cancers (n = 1261) including our lung cancer cohort (n = 497). Deconvolution of spatial transcriptomes discriminates TLS-enriched from non-enriched cell types among immunotherapy-favorable components. Our systematic dissection of tumor-normal ecosystems provides a deeper understanding of inter- and intra-tumoral heterogeneity.
    DOI:  https://doi.org/10.1038/s41467-024-48310-4
  2. Diagnostics (Basel). 2024 Apr 30. pii: 949. [Epub ahead of print]14(9):
      One of the greatest challenges in modern gynecological oncology is ovarian cancer. Despite the numerous studies currently being conducted, it is still sometimes detected at late clinical stages, where the prognosis is unfavorable. One significant contributing factor is the absence of sensitive and specific parameters that could aid in early diagnosis. An ideal screening test, in view of the low incidence of ovarian cancer, should have a sensitivity of greater than 75% and a specificity of at least 99.6%. To enhance sensitivity and specificity, diagnostic panels are being created by combining individual markers. The drive to develop better screening tests for ovarian cancer focuses on modern diagnostic methods based on molecular testing, which in turn aims to find increasingly effective biomarkers. Currently, researchers' efforts are focused on the search for a complementary parameter to those most commonly used that would satisfactorily enhance the sensitivity and specificity of assays. Several biomarkers, including microRNA molecules, autoantibodies, cDNA, adipocytokines, and galectins, are currently being investigated by researchers. This article reviews recent studies comparing the sensitivity and specificity of selected parameters used alone and in combination to increase detection of ovarian cancer at an early stage.
    Keywords:  biomarkers; ovarian cancer; sensitivity; specificity
    DOI:  https://doi.org/10.3390/diagnostics14090949
  3. Reprod Sci. 2024 May 15.
       PURPOSE: Ovarian cancer is oftendiagnosed late due to vague symptoms, leading to poor survival rate. Improved screening tests could mitigate this issue. This narrative review examines the potential and challenges of integrating artificial intelligence (A.I.) into ovarian cancer screenings, with a focus on improving early detection, diagnosis, and personalized risk assessment.
    METHOD: A comprehensive review of existing literature was conducted, analyzing studies and discussions within the scientific community.
    RESULTS: A.I. shows promise in significantly improving the ovarian cancer screening processes, increasing accuracy, efficiency, and resource allocation. However, data quality and bias issues pose considerable challenges, potentially leading to healthcare disparities.
    CONCLUSIONS: Integrating A.I. into ovarian cancer screenings offers potential benefits but comes with significant challenges. By promoting diverse data collection, engaging with underrepresented groups, and ensuring ethical data use, A.I. can be harnessed for more accurate and equitable ovarian cancer diagnoses.
    Keywords:  Artificial intelligence; Diagnosis; Machine learning; Ovarian Cancer; Screening
    DOI:  https://doi.org/10.1007/s43032-024-01588-7
  4. Sci Rep. 2024 05 14. 14(1): 11048
      Information about cell composition in tissue samples is crucial for biomarker discovery and prognosis. Specifically, cancer tissue samples present challenges in deconvolution studies due to mutations and genetic rearrangements. Here, we optimized a robust, DNA methylation-based protocol, to be used for deconvolution of ovarian cancer samples. We compared several state-of-the-art methods (HEpiDISH, MethylCIBERSORT and ARIC) and validated the proposed protocol in an in-silico mixture and in an external dataset containing samples from ovarian cancer patients and controls. The deconvolution protocol we eventually implemented is based on MethylCIBERSORT. Comparing deconvolution methods, we paid close attention to the role of a reference panel. We postulate that a possibly high number of samples (in our case: 247) should be used when building a reference panel to ensure robustness and to compensate for biological and technical variation between samples. Subsequently, we tested the performance of the validated protocol in our own study cohort, consisting of 72 patients with malignant and benign ovarian disease as well as in five external cohorts. In conclusion, we refined and validated a reference-based algorithm to determine cell type composition of ovarian cancer tissue samples to be used in cancer biology studies in larger cohorts.
    Keywords:  DNA methylation; Ovarian cancer; Reference-based deconvolution; Tissue heterogeneity
    DOI:  https://doi.org/10.1038/s41598-024-61857-y
  5. Nat Commun. 2024 May 16. 15(1): 4134
      Defining the number and abundance of different cell types in tissues is important for understanding disease mechanisms as well as for diagnostic and prognostic purposes. Typically, this is achieved by immunohistological analyses, cell sorting, or single-cell RNA-sequencing. Alternatively, cell-specific DNA methylome information can be leveraged to deconvolve cell fractions from a bulk DNA mixture. However, comprehensive benchmarking of deconvolution methods and modalities was not yet performed. Here we evaluate 16 deconvolution algorithms, developed either specifically for DNA methylome data or more generically. We assess the performance of these algorithms, and the effect of normalization methods, while modeling variables that impact deconvolution performance, including cell abundance, cell type similarity, reference panel size, method for methylome profiling (array or sequencing), and technical variation. We observe differences in algorithm performance depending on each these variables, emphasizing the need for tailoring deconvolution analyses. The complexity of the reference, marker selection method, number of marker loci and, for sequencing-based assays, sequencing depth have a marked influence on performance. By developing handles to select the optimal analysis configuration, we provide a valuable source of information for studies aiming to deconvolve array- or sequencing-based methylation data.
    DOI:  https://doi.org/10.1038/s41467-024-48466-z
  6. Nat Med. 2024 May 15.
    FLAMES Investigators
      Poly(adenosine diphosphate-ribose) polymerase (PARP) inhibitors as maintenance therapy after first-line chemotherapy have improved progression-free survival in women with advanced ovarian cancer; however, not all PARP inhibitors can provide benefit for a biomarker-unselected population. Senaparib is a PARP inhibitor that demonstrated antitumor activity in patients with solid tumors, including ovarian cancer, in phase 1 studies. The multicenter, double-blind, phase 3 trial FLAMES randomized (2:1) 404 females with advanced ovarian cancer (International Federation of Gynecology and Obstetrics stage III-IV) and response to first-line platinum-based chemotherapy to senaparib 100 mg (n = 271) or placebo (n = 133) orally once daily for up to 2 years. The primary endpoint was progression-free survival assessed by blinded independent central review. At the prespecified interim analysis, the median progression-free survival was not reached with senaparib and was 13.6 months with placebo (hazard ratio 0.43, 95% confidence interval 0.32-0.58; P < 0.0001). The benefit with senaparib over placebo was consistent in the subgroups defined by BRCA1 and BRCA2 mutation or homologous recombination status. Grade ≥3 treatment-emergent adverse events occurred in 179 (66%) and 27 (20%) patients, respectively. Senaparib significantly improved progression-free survival versus placebo in patients with advanced ovarian cancer after response to first-line platinum-based chemotherapy, irrespective of BRCA1 and BRCA2 mutation status and with consistent benefits observed between homologous recombination subgroups, and was well tolerated. These results support senaparib as a maintenance treatment for patients with advanced ovarian cancer after a response to first-line chemotherapy. ClinicalTrials.gov identifier: NCT04169997 .
    DOI:  https://doi.org/10.1038/s41591-024-03003-9
  7. bioRxiv. 2024 Apr 29. pii: 2024.04.26.587806. [Epub ahead of print]
      Improvements in single-cell whole-genome sequencing (scWGS) assays have enabled detailed characterization of somatic copy number alterations (CNAs) at the single-cell level. Yet, current computational methods are mostly designed for detecting chromosome-scale changes in cancer samples with low sequencing coverage. Here, we introduce HiScanner (High-resolution Single-Cell Allelic copy Number callER), which combines read depth, B-allele frequency, and haplotype phasing to identify CNAs with high resolution. In simulated data, HiScanner consistently outperforms state-of-the-art methods across various CNA types and sizes. When applied to high-coverage scWGS data from human brain cells, HiScanner shows a superior ability to detect smaller CNAs, uncovering distinct CNA patterns between neurons and oligodendrocytes. For 179 cells we sequenced from longitudinal meningioma samples, integration of CNAs with point mutations revealed evolutionary trajectories of tumor cells. These findings show that HiScanner enables accurate characterization of frequency, clonality, and distribution of CNAs at the single-cell level in both non-neoplastic and neoplastic cells.
    DOI:  https://doi.org/10.1101/2024.04.26.587806
  8. Int J Oncol. 2024 Jun;pii: 62. [Epub ahead of print]64(6):
      Ovarian cancer (OC) represents the most prevalent malignancy of the female reproductive system. Its distinguishing features include a high aggressiveness, substantial morbidity and mortality, and a lack of apparent symptoms, which collectively pose significant challenges for early detection. Given that aberrant DNA methylation events leading to altered gene expression are characteristic of numerous tumor types, there has been extensive research into epigenetic mechanisms, particularly DNA methylation, in human cancers. In the context of OC, DNA methylation is often associated with the regulation of critical genes, such as BRCA1/2 and Ras‑association domain family 1A. Methylation modifications within the promoter regions of these genes not only contribute to the pathogenesis of OC, but also induce medication resistance and influence the prognosis of patients with OC. As such, a more in‑depth understanding of DNA methylation underpinning carcinogenesis could potentially facilitate the development of more effective therapeutic approaches for this intricate disease. The present review focuses on classical tumor suppressor genes, oncogenes, signaling pathways and associated microRNAs in an aim to elucidate the influence of DNA methylation on the development and progression of OC. The advantages and limitations of employing DNA methylation in the diagnosis, treatment and prevention of OC are also discussed. On the whole, the present literature review indicates that the DNA methylation of specific genes could potentially serve as a prognostic biomarker for OC and a therapeutic target for personalized treatment strategies. Further investigations in this field may yield more efficacious diagnostic and therapeutic alternatives for patients with OC.
    Keywords:  DNA methylation; oncogenes; ovarian cancer; pathways; tumor suppressor genes
    DOI:  https://doi.org/10.3892/ijo.2024.5650