MSS colorectal cancer

Subtype of Colorectal cancer

Clinical / Scientific

Most CRCs are MSS/pMMR, immune-colder, and checkpoint-refractory as monotherapy. Wnt, RAS and remain dominant maps. Adjunctive immune-modulation hypotheses should not be presented as equivalent to MSI-high checkpoint success.

Core Biological Drivers

APC/Wnt

Canonical chromosomal-instability path.

RAS/RAF

dependence in a large subset.

Immune-cold stroma

TGF-β and myeloid exclusion.

Key Pathways

Wnt/β-catenin

Scientific explanation

Canonical Wnt signalling stabilizes β-catenin, driving TCF/LEF . APC loss is a classic colorectal initiating event; the pathway also contributes to stemness in several tissues.

RAS/RAF

Scientific explanation

RAS GTPases and RAF kinases are frequent oncogenic nodes. KRAS, NRAS and BRAF mutations lock mitogenic signalling on in a ligand-independent way in many tumours.

MAPK/ERK

Scientific explanation

The RAS–RAF–MEK–ERK cascade transmits mitogenic RTK signals to programmes for proliferation and differentiation.

TGF-β

Scientific explanation

TGF-β is cytostatic in intact epithelium but later supports , immune suppression and stromal . Context switches its role during progression.

VEGF

Scientific explanation

family ligands drive endothelial sprouting and vascular permeability, a canonical tumour axis.

COX / inflammatory signalling

Scientific explanation

-2–PGE2 signalling can promote , immune suppression and epithelial proliferation, notably in colorectal neoplasia.

EMT

Scientific explanation

Epithelial–mesenchymal plasticity, driven by TWIST/SNAIL/ZEB and TGF-β/Wnt/Notch inputs, reduces adhesion and increases motility and stem-like features.

Pathway Convergence

Target → pathway → downstream effect → biological consequence. Shared intersections are mechanistic maps, not protocols.

Growth-factor signalling

Ligand or mutation-driven RTK input feeds PI3K/AKT and mTORC1, supporting anabolic growth. This is a map of signalling, not a treatment protocol.

Receptor tyrosine kinase
↓
PI3K/AKT
↓
mTOR
↓
Protein synthesis / growth

Hypoxia to vessels

Low oxygen stabilizes HIF-1α, inducing VEGF and endothelial sprouting. Anti-angiogenic pharmacology intersects this axis but does not erase the tumour ecosystem.

Hypoxia
↓
HIF-1α
↓
VEGF
↓
Angiogenesis

Inflammatory survival

Chronic cytokine tone activates NF-κB and STAT3 transcriptional programmes that favour survival, invasion and sometimes immune evasion.

Cytokines
↓
NF-κB / STAT3
↓
Survival and invasion genes
↓
Therapy-tolerant phenotype

Metabolic Vulnerabilities

Aerobic supports ATP, biomass and acidification even when oxygen is available. Extent varies by tumour and remains a vulnerability hypothesis rather than a uniform target.

Tumor Microenvironment

Cancer-associated fibroblasts, TGF-β and extracellular-matrix stiffness can compress vessels and exclude T cells, especially in desmoplastic tumours.

Tumour-associated macrophages and myeloid-derived suppressor cells secrete cytokines that support invasion and blunt cytotoxic T cells.

Metastasis Module

, protease-mediated invasion, , circulating tumour-cell survival and organ-specific colonization form the metastatic cascade. Pre-metastatic niches and vascular permeability influence tropism.

Resistance Biology

Resistance can arise from drug efflux, secondary mutations, bypass RTK signalling, apoptotic threshold elevation, -mediated survival, metabolic adaptation and lineage plasticity.

Cancer Stemness

Wnt, Notch, Hedgehog, ALDH and CD44-associated programmes can mark stem-like fractions with quiescence and therapy tolerance. These markers are not interchangeable across tumour types.

Mechanism-Based Adjunctive Strategies

Compounds appear only where a mechanistic overlap exists for this cancer. Evidence tiers are not equivalent. Nothing here is a treatment recommendation.

Niclosamide

In VitroIn VivoMechanistically Plausible

Target / Mechanism

uncoupler in cestodes; mammalian models report , Wnt/β-catenin and modulation. Those host-signalling findings are investigational/preclinical.

Cancer relevance

Models report Wnt/β-catenin, and effects. Host signalling findings remain investigational.

Wnt / STAT3 signalling models. Convergence: Wnt/β-catenin, JAK/STAT, mTOR.

Celecoxib

Clinical / Human EvidenceIn VivoIn Vitro

Target / Mechanism

Selective -2 reducing PGE2. Relevant to -associated epithelial neoplasia; cardiovascular risk and lack of broad anticancer approval constrain interpretation.

Cancer relevance

-2/PGE2 biology is relevant in some epithelial neoplasias. Cardiovascular risk and lack of broad anticancer approval apply. Do not equate polyp or biomarker studies with tumour cure.

Inflammation-associated epithelial neoplasia research. Convergence: COX / inflammatory signalling, Angiogenesis.

Metformin

Clinical / Human EvidenceIn VivoIn VitroMechanistically Plausible

Target / Mechanism

Modest complex I inhibition raises AMP:ATP, activating and restraining hepatic and -linked anabolism. Direct antineoplastic efficacy is not established from that pharmacology alone.

Cancer relevance

activation and restraint provide a metabolic rationale in - and -linked tumours. Human data are mixed and do not establish metformin as cancer therapy.

Metabolic adjunctive research context. Convergence: AMPK, mTOR, Glycolysis.

Losartan

Early ClinicalIn VivoMechanistically Plausible

Target / Mechanism

AT1- . In desmoplastic models, angiotensin blockade can reduce TGF-β-linked stromal compression and improve perfusion; this is adjunctive stromal biology, not cytotoxic oncology.

Cancer relevance

AT1 blockade can reduce TGF-β-linked desmoplasia and improve perfusion in models, notably pancreatic. Stromal decompression is not cytotoxicity.

Stroma / perfusion adjunctive research. Convergence: TGF-β, Angiogenesis.

Curcumin

In VitroMechanistically Plausible

Target / Mechanism

Polyphenol with promiscuous in-vitro NF-κB, and ROS effects. Bioavailability is poor; dish activity does not establish clinical anticancer efficacy.

Cancer relevance

In-vitro NF-κB/ effects are frequent. Poor bioavailability and absence of robust clinical anticancer efficacy keep this pathway-level.

Inflammatory-signalling dish models. Convergence: NF-κB, JAK/STAT.

Research Context

  1. CRC adenoma-carcinoma. Fearon ER, Vogelstein B. A genetic model for colorectal tumorigenesis. Cell. 1990;61(5):759-767. https://doi.org/10.1016/0092-8674(90)90186-I
  2. CRC TCGA. The Cancer Genome Atlas Network. Comprehensive molecular characterization of human colon and rectal cancer. Nature. 2012;487(7407):330-337. https://doi.org/10.1038/nature11252

This oncology atlas is educational. Pathway maps, adjunctive strategies, and compound listings describe mechanistic relevance. They do not establish clinical efficacy, do not recommend treatment, and are not a substitute for oncology care. Evidence tiers are not equivalent.