# Breast cancer research on osteopontin protein

> Live situation record from CLSTR: https://clstr.news/situations/breast-cancer-research-on-osteopontin-protein
> Updated: 2026-09-18T12:14:43.000Z. Sources: 11. Developments: 2.

Researchers at the Spanish National Cancer Research Centre (CNIO) have identified the osteopontin protein as a significant factor in breast cancer treatment resistance. The study indicates that tumor cells produce osteopontin in response to hypoxia caused by antiangiogenic drugs.

This protein functions by reprogramming immune cells to protect the tumor instead of attacking it, which diminishes the effectiveness of immunotherapy and antiangiogenic therapies. In animal models, blocking osteopontin reduced tumor hypoxia and enabled the immune system to destroy cancer cells, suggesting that targeting this protein could enhance the efficacy of existing treatments.

## Timeline

### 2026-09-18: Cancer research identifies osteopontin protein as new treatment target

New research identifies the osteopontin protein as a target to overcome cancer treatment resistance, while the AACR reports significant therapeutic advances alongside a rising global cancer burden.

3 sources. https://clstr.news/cluster/cancer-research-identifies-osteopontin-protein-as-new-treatment-target

### 2026-09-03: CNIO researchers identify osteopontin protein as target for breast cancer treatment

CNIO researchers identified the osteopontin protein as a driver of resistance to breast cancer treatments, offering a new target to improve antiangiogenic and immunotherapy effectiveness.

7 sources. https://clstr.news/cluster/cnio-researchers-identify-osteopontin-protein-as-target-for-breast-cancer-treatment

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Cite as: Breast cancer research on osteopontin protein. CLSTR, https://clstr.news/situations/breast-cancer-research-on-osteopontin-protein