Current applications of molecular pathology in colorectal carcinoma

Ferroptosis-associated gene CISD2 suppresses colon cancer development by regulating tumor immune microenvironment

Background

Despite the association of ferroptosis with various tumors, the specific mechanism by which it influences colon adenocarcinoma (COAD) microenvironmental equilibrium remains elusive. This study aims to elucidate how ferroptosis affects COAD microenvironmental homeostasis and its potential impact on COAD research.

Objective

By employing genetic screening and single-cell analysis of tumor data, we investigated the role of ferroptosis genes in COAD microenvironmental homeostasis. The genes were correlated with immune cell infiltration in tissue samples and patient outcomes.

Methods

Ferroptosis-associated genes were initially identified through the FerrDb database. Utilizing the tidyverse and Seurat packages, genes with substantial expression differences were extracted, and clustering analysis was performed on the single-cell data. A Venn diagram depicted shared differential genes for ferroptosis and tumors. To screen key ferroptosis genes, further enrichment analysis and immune cell infiltration analysis were conducted. Lastly, human COAD cell lines were employed to overexpress CDGSH iron sulfur domain 2 (CISD2) through cellular assays to validate its function in COAD.

Results

Following screening of The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) databases, 414 COAD patient samples and 341 normal samples were included. Through the FerrDb database, 259 ferroptosis genes were identified. Clustering the single-cell data revealed 911 tumor marker genes, of which 18 were ferroptosis genes. Analysis of variance (ANOVA) and univariate regression analysis determined that only CISD2 was statistically significantly associated with clinical outcomes. Additionally, CISD2 was found to positively correlate with activated memory T cells and negatively correlate with regulatory T cells (Tregs) and plasma cells in COAD, as well as being significantly associated with several immune-related and cancer-related pathways. CISD2 expression was elevated in most tumors, likely due to cell cycle regulation and immune system activation. Moreover, CISD2 upregulation inhibited COAD cell proliferation and enhanced 5-fluorouracil (5-FU) sensitivity. Our findings indicate, for the first time, that CISD2 governs the cell cycle and stimulates the immune system to impede COAD progression.

Conclusion

By modulating the cell cycle and mediating immune infiltration, CISD2 may inhibit COAD development by influencing tumor immune microenvironment equilibrium, providing valuable insights into the relevance and potential impact of the research results on the COAD research field.

Molecular Biomarkers: A Review of Multiple Applications in Clinical Care of Colorectal Cancer

BACKGROUND

Advancements in tumor profiling have identified multiple molecular biomarkers that influence tumor growth and behavior. Molecular biomarkers provide clinical prognostic and predictive information, which guides treatment decisions and forms the backbone of precision oncology.

OBJECTIVES

This article identifies key predictive and prognostic molecular biomarkers used in the treatment of colorectal cancer and provides greater understanding of their biologic significance and usefulness in guiding treatment decisions.

METHODS

A review of the literature and professional guidelines was performed to evaluate approved molecular biomarkers, targeted agents, and tumor testing modalities used for the management and treatment of colorectal cancer, with an emphasis on treatment decision making.

FINDINGS

Genomic biomarkers are increasingly used for the prevention, diagnosis, prognostication, and management of colorectal cancer. The introduction of targeted agents and advancements in tumor profiling technologies have increased treatment opportunities and improved clinical outcomes for patients with colorectal cancer.

The Role of the Immune Infiltrate in Distinct Cancer Types and Its Clinical Implications : Lymphocytic Infiltration in Colorectal Cancer

Colorectal cancer (CRC) represents a major public health challenges, with one of the highest incidences worldwide. The two affected anatomical sites in CRC, i.e. the colon and the rectum, share important underlying features, but often differ in terms of therapeutic management. Current guidelines for CRC define its clinical stratification according to classical, tumor cell-based and pathological parameters. Novel ground-breaking findings in the recent years revealed the prominent role of the immune system in shaping CRC development. This chapter provides a detailed overview of the main genomic and immune features driving (or hampering) CRC progression, with a focus on the main immune cells and factors shaping its evolution. Furthermore, we discuss how tumor-infiltrating immunity could be leveraged both for therapeutic and stratification purposes.

Immunohistochemistry in screening for heritable colorectal cancer: what to do with an abnormal result

Recent developments in our understanding of molecular genetics have transformed screening and diagnostic practices for Lynch syndrome. The current standard involves universal tumour analysis of resected colorectal cancer (and ideally polypectomy) specimens using immunohistochemistry and molecular techniques. Patients with abnormal immunohistochemical findings are subsequently referred for definitive mutational testing. This review relates the molecular pathogenesis of Lynch syndrome to current immunohistochemistry-based screening strategies and discusses the interpretation and clinical implications of screening results.