The Breakthrough at ICR: Targeting LOX in Lobular Breast Cancer

In a significant advancement for breast cancer research, scientists at The Institute of Cancer Research (ICR), London, have identified a promising treatment avenue for invasive lobular carcinoma (ILC), the second most common form of breast cancer. Published in the prestigious journal Cancer Research on April 13, 2026, the study highlights the potential of a lysyl oxidase (LOX) inhibitor to halt tumor progression. ILC, which constitutes about 15% of all breast cancer cases in the UK—equating to roughly 8,400 diagnoses annually—has long been underserved by targeted therapies. This research, led by experts from ICR's Breast Cancer Now Toby Robins Research Centre, could reshape treatment paradigms for this insidious subtype.

ILC differs markedly from the more prevalent invasive ductal carcinoma (IDC). Rather than forming solid masses, ILC cells spread in single-file lines through breast tissue, evading early detection on mammograms and complicating surgical planning. Patients often present with advanced disease, and while many ILCs are estrogen receptor-positive (ER+), leading to initial responses to hormone therapies like tamoxifen, recurrence rates remain high, particularly after five years. This study's focus on the tumor microenvironment—specifically the role of LOX in stiffening collagen fibers—offers a novel mechanistic insight, positioning UK research institutions like ICR at the forefront of precision oncology.

Understanding Invasive Lobular Carcinoma: A UK Perspective

In the United Kingdom, breast cancer remains the most common cancer among women, with over 55,000 new cases each year. Within this, ILC's share of 15% underscores its clinical relevance, yet it lags in research funding and trial inclusion. According to NHS England data released by Lobular Breast Cancer UK (LBCUK), around 8,400 women receive an ILC diagnosis annually. The subtype's diffuse growth pattern, driven by loss of the CDH1 gene (encoding E-cadherin), enables infiltration without a palpable lump, delaying diagnosis by up to a year compared to IDC.

Treatment challenges are compounded by ILC's resistance to standard chemotherapy and higher propensity for peritoneal and gastrointestinal metastases. Survival rates, while favorable early on (over 90% five-year for localized disease), drop significantly with spread. UK clinicians report frustration with one-size-fits-all approaches, as ILC responds poorly to neoadjuvant therapies. This gap has spurred advocacy from groups like Breast Cancer Now, which launched the £1 million Lobular Initiative to accelerate ILC-specific studies at centres like ICR.

The Role of LOX in Tumor Progression

Lysyl oxidase (LOX) is an enzyme secreted by cancer cells that cross-links collagen in the extracellular matrix (ECM), creating a rigid scaffold that facilitates invasion and metastasis. In ILC, LOX hyperactivity stiffens the ECM, activating integrin signaling—particularly αvβ5 (ITGAV/ITGB5)—which drives MYC and AP-1 transcription factors, promoting proliferation and survival. Genome-wide CRISPR screens in the ICR study confirmed ITGAV and ITGB5 as synthetic lethal partners with CDH1 loss, a hallmark of ILC.

This collagen-integrin-MYC axis explains ILC's aggressiveness. High collagen density correlates with poor prognosis, and LOX inhibition disrupts fiber alignment, starving cells of mechanical cues. Earlier ICR work (2007, 2017) laid groundwork by linking LOX to metastasis, but this study uniquely applies it to ILC models.

Innovative Preclinical Models Driving Discovery

A cornerstone of the research was ICR's development of intraductal patient-derived xenografts (PDX). Using donated tumor samples, researchers implanted ILC cells into mouse mammary ducts, recapitulating human disease diversity across ER+ and triple-negative subtypes. These models overcame prior limitations—ILC's slow growth and imaging challenges—allowing precise evaluation of tumor expansion and metastatic seeding.

• PDX tumors treated with PXS-5505 showed remodeled fibrillar collagen and halted progression.
• No systemic toxicity observed, mirroring Phase I/IIa safety in myelofibrosis trials.
• Pharmacodynamic markers: reduced collagen density/alignment and downregulated MYC/AP-1 signatures.

This methodological leap, pioneered by Professor Cathrin Brisken (now at EPFL, formerly ICR) and Dr. Renée Flaherty, equips UK labs for future ILC studies.

PXS-5505: From Myelofibrosis to Breast Cancer Repurposing

PXS-5505, a pan-LOX inhibitor from Pharmaxis/Syntara, targets LOX and LOXL isoforms. Already in human trials for fibrosis-driven diseases, its clean safety profile (no dose-limiting toxicities) de-risks translation. In ICR models, it curtailed primary tumor growth and metastasis without impacting healthy tissues. For more on its profile, see the ongoing HCC trial, demonstrating tolerability with immunotherapy.

Repurposing accelerates timelines; ICR plans window-of-opportunity trials (91 patients) to assess neoadjuvant efficacy, potentially combined with endocrine therapy to counter JUN-mediated resistance.

Photo by Giammarco Boscaro on Unsplash

Spotlight on ICR Researchers and Collaborations

Dr. Clare Isacke (ICR) and Professor Cathrin Brisken spearheaded the effort, with contributions from global partners including EPFL, Crick Institute, and AstraZeneca. Dr. Renée Flaherty, a postdoctoral fellow, emphasized the 'dedication required' for ILC models. Professor Brisken noted: “Things are moving in the right direction... The next stage will be clinical trials.” ICR's Toby Robins Centre, funded by Breast Cancer Now, exemplifies UK higher ed's translational prowess.

As a specialist postgraduate institute partnered with the University of London, ICR trains PhD students in cutting-edge oncology, fostering the next generation of researchers.

UK Higher Education's Leadership in Cancer Research

ICR's feat underscores the UK's biomedical research strength. With £1.5bn annual CRUK funding and UKRI support, institutions like ICR, CRUK Manchester, and Edinburgh Cancer Research Centre drive ILC progress. The Lobular Initiative (£5m over 5 years) unites Toby Robins experts, amplifying impact. UK universities excel in patient-derived models and ECM research, attracting global talent.

Challenges persist: ILC underrepresentation (despite 15% prevalence) mirrors funding gaps—only 5% of trials subtype-stratify. Yet, initiatives like NIHR's ILC highlight notice signal commitment.

Patient Impact and Advocacy Momentum

For UK patients, this offers hope amid 11,500 annual breast cancer deaths (projected stable to 2040). LBCUK and Breast Cancer Now advocate for ILC-specific trials, spotlighting 22 daily diagnoses. Early adopters may benefit from LOX biomarkers predicting response, personalizing care.

Real-world cases: Women like those in ICR trials report late recurrences; targeted LOX therapy could prevent this.

Future Directions: Trials, Combinations, and Challenges

Next: Funding bids for Phase II trials testing PXS-5505 pre-surgery. Combinations with CDK4/6 inhibitors or immunotherapy loom. Challenges: ILC's heterogeneity demands diverse models; regulatory hurdles for repurposed drugs.

Optimism prevails: “We’ve uncovered a tractable axis,” per the paper. UK higher ed must sustain momentum via REF2029 and Horizon Europe.

Career Opportunities in UK Cancer Research

This breakthrough spotlights vibrant careers at ICR and partner unis. PhD programs (via London/Sutton), postdocs in ECM biology, faculty in translational oncology abound. With 2,000+ researchers, ICR offers research roles; unis like UCL/ICR collaborations yield postdocs. Salaries: £40k+ starting postdoc, £60k+ lecturer. Explore CV tips for entry.

Photo by Annie Spratt on Unsplash

Outlook: Transforming ILC Prognosis

ICR's LOX work heralds a new era for ILC, blending UK higher ed innovation with patient needs. As trials advance, expect biomarkers guiding therapy, reducing UK's 73% 10-year ILC survival burden. For researchers, it's a call to ILC focus—funding follows impact.