Cancer / Oncology/ER+ breast cancer
Breast · subtype
ER+ breast cancer
Subtype of Breast cancer
Clinical / Scientific
ER-positive disease depends on ERα transcriptional programmes and is commonly -altered. Endocrine therapy is established; / and CDK4/6 biology dominate resistance research.
Core Biological Drivers
ERα (ESR1)
Ligand-activated nuclear- .
PIK3CA / PTEN
Frequent -pathway lesions.
Cyclin D–CDK4/6–RB
Cell-cycle control cooperating with ER.
Key Pathways
Scientific explanation
ERα (ESR1) drives a large fraction of breast cancers via genomic and non-genomic signalling. ESR1 mutations and growth-factor crosstalk contribute to endocrine resistance.
Scientific explanation
phosphorylates PIP2 to PIP3, recruiting . supports growth, survival, glucose uptake and mTORC1 input. Pathway activation is common via PIK3CA mutation, PTEN loss or -tyrosine- signalling.
Scientific explanation
mTORC1 integrates growth-factor and nutrient signals to drive protein synthesis, lipid synthesis and suppression. It sits downstream of PI3K/AKT and amino-acid sensing.
Scientific explanation
Intrinsic and extrinsic apoptotic programmes remove damaged cells. Evasion of is a hallmark, via BCL-2 family imbalance, death- decoys, or p53 loss.
Scientific explanation
Aerobic (Warburg metabolism) supports ATP, biomass and redox buffering even when oxygen is available. Hexokinase, PKM2 and lactate export are frequent nodes.
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.
Energy stress
Energetic stress activates AMPK, which can restrain mTORC1. Biguanides and related tools map onto this axis in models.
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.
/IGF can transactivate ER and .
Tumor Microenvironment
Disordered vasculature creates , HIF-1α stabilization, induction and immune-suppressive adenosine/lactate milieus.
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
ESR1 mutations, CDK pathway change and RTK/ reactivation drive endocrine resistance.
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.
Target / Mechanism
Selective estrogen- modulator that antagonizes ERα-driven in breast epithelium while retaining partial activity in some other tissues.
Cancer relevance
Established SERM therapy for hormone--positive breast cancer according to labelled oncology practice. Tissue-specific / balance still applies.
Labelled endocrine therapy context. Convergence: Estrogen receptor, Apoptosis.
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.
Statins (HMG-CoA reductase inhibitors)
Target / Mechanism
Inhibit HMG-CoA reductase, depleting mevalonate-pathway isoprenoids needed for RAS/RHO prenylation and some sterol-dependent growth programmes. Observational oncology signals are mixed and not a licence to treat cancer with statins.
Cancer relevance
Mevalonate-pathway blockade can affect prenylation of RAS-family GTPases. Observational human signals are mixed and confounding is substantial.
Mevalonate / prenylation mechanistic overlap. Convergence: RAS/RAF, Fatty-acid metabolism.
Berberine
Target / Mechanism
Isoquinoline alkaloid that can inhibit complex I and activate in metabolic models, with additional -independent reports. Not an approved antineoplastic.
Cancer relevance
Complex I / pharmacology overlaps metformin-like energy stress in models. Bioavailability and lack of oncology indication keep this mechanistic.
Metabolic energy-stress hypothesis. Convergence: AMPK, mTOR, Mitochondrial oxidative phosphorylation.
Celecoxib
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.
Research Context
- Breast portraits. Perou CM, et al. Molecular portraits of human breast tumours. Nature. 2000;406(6797):747-752. https://doi.org/10.1038/35021093
- Tamoxifen. Jordan VC. Tamoxifen: a most unlikely pioneering medicine. Nat Rev Drug Discov. 2003;2(3):205-213. https://doi.org/10.1038/nrd1031
- Metformin oncology. Pollak MN. Investigating metformin for cancer prevention and treatment: the end of the beginning. Cancer Discov. 2012;2(9):778-790. https://doi.org/10.1158/2159-8290.CD-12-0263
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.