Methylene Blue and Breast Cancer: The Breakthrough You Haven’t Heard About

In 2017, researchers at the University of São Paulo published a study that should have made headlines around the world. The paper—titled Methylene blue photodynamic therapy induces selective and massive cell death in human breast cancer cells (Dos Santos et al., 2017)—showed that methylene blue, a low-cost and century-old compound, can kill aggressive breast cancer cells while sparing normal, healthy ones.

It was a breakthrough moment.
And yet… nearly no one talks about it.

This blog explains why it matters, what the study actually showed, and how this therapy could change lives—especially for those facing the most aggressive types of breast cancer.

What Is Methylene Blue Photodynamic Therapy (MB-PDT)?

Photodynamic therapy using methylene blue involves two steps:

1. Apply methylene blue (MB) to the target cells.
2. Activate it with red light—specifically, light at a wavelength of 640 nm.

This activation produces reactive oxygen species (ROS) within the cells, selectively damaging and killing cancer cells, while largely leaving healthy cells alone.

The Study: Targeting 3 Types of Breast Cells

Researchers tested MB-PDT on three different breast cell types:

• MCF-10A – normal, healthy breast cells
• MCF-7 – estrogen-positive breast cancer
• MDA-MB-231 – triple-negative breast cancer (TNBC), one of the most aggressive and treatment-resistant forms

Cells were treated with either 2µM or 20µM methylene blue and then exposed to 4.5 J/cm² of red light.

What Happened: The Results Were Stunning

The results were nothing short of groundbreaking:

• Up to 100% of cancer cells were killed.
• Healthy cells remained largely intact.
• Triple-negative breast cancer (TNBC) cells showed the highest death rates.

Importantly, all cell types absorbed similar amounts of methylene blue. The key difference?
Cancer cells—especially TNBC—had much lower glutathione (GSH) levels, making them more vulnerable to the oxidative damage triggered by MB-PDT.

In 3D Tumor Models? Still Works.

To take it a step further, researchers tested MB-PDT on 3D spheroids—structures that mimic real tumors more accurately than flat 2D cultures.

Even under these more realistic conditions:

• Cancer cells still died in large numbers
• Healthy cells remained largely unharmed

This is what modern cancer therapy should aim for: selective killing without collateral damage.

Why Hasn’t This Gone Mainstream?

The science is solid. So why isn’t methylene blue photodynamic therapy available in every cancer center?

The unfortunate truth is that pharmaceutical economics often shape medical adoption. Methylene blue is off-patent, inexpensive, and widely available—meaning there’s little financial incentive for large-scale clinical trials or industry-backed promotion.

It’s not a conspiracy—it’s a funding gap.

But that doesn’t make the science any less powerful. It just means we need to advocate harder for accessible, promising therapies like MB-PDT.

What Could MB-PDT Be Used For?

This therapy shows immense potential, especially in hard-to-treat cancers. Potential applications include:

• Post-surgery: to eliminate remaining cancer cells
• Radiation alternative: especially in sensitive or high-risk tissue areas
• Triple Negative Breast Cancer: which currently has no targeted treatments

Quality You Can Trust

It’s critical to know that not all methylene blue is created equal. Industrial-grade MB may contain heavy metals or solvents—not suitable for human use.

At AP Labs South Africa, we offer pharmaceutical-grade methylene blue that is:

• Triple third-party tested
• Backed by a Certificate of Analysis (COA)
• 100% suitable for clinical and personal wellness applications

Final Word

This 2017 study should have been a turning point in breast cancer treatment. It showed that a safe, selective, affordable therapy already exists—yet it was quietly shelved instead of celebrated.

We’re here to change that.

Let’s bring the science back into the spotlight.

Recovering From A Stroke? Science Says Methylene Blue Can Make A Difference.

➡️ Read the full peer-reviewed study
➡️ Explore pharmaceutical-grade methylene blue at AP Labs