When GBM Entered Our Lives

When Christina was diagnosed with Glioblastoma (GBM) in February 2020, our world flipped upside down. The idea of losing my wife to cancer became a terrifying reality. Emotions were chaotic, and thinking clearly felt impossible.

Our first instinct was to learn everything we could about this disease. Information came at us fast and from every direction. The most shocking fact? GBM is the most common primary malignant brain tumor in adults, with a median survival of only 15 months (1).

Treatment usually begins with a biopsy and tumor removal, followed by radiotherapy and chemotherapy with alkylating agents. Christina received temozolomide (TMZ), and later bevacizumab, a monoclonal antibody that blocks the tumor’s blood supply (10).

I’ve decided to write a series of posts documenting what I’ve learned about GBM and my ideas—naïve though they may be—about how we might improve outcomes for patients, from the perspective of a chemist.

During my chemistry career (1984–1998), I worked on synthesizing diagnostic reagents and anti-cancer drugs. I thought that knowledge might allow me to help Christina—and, in my hope, even save her.

Even though the current standard of care is limited, I believe there is still much that science can do for people facing this disease.

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Understanding MGMT

When DNA in a cell is damaged, repair mechanisms kick in to maintain genetic integrity. Damage can come from the environment—or even from the normal process of DNA replication. Most errors are corrected, but some slip through. Some mutations drive evolution; others lead to cancer.

Why MGMT Matters

Alkylating chemotherapy targets DNA by adding methyl groups to guanine at the oxygen-6 position. MGMT (methylguanine-DNA methyltransferase) is an enzyme that repairs this damage. By removing the methyl group, MGMT allows cancer cells to survive chemotherapy.

In GBM, knowing whether MGMT is active is critical. Tumors lacking this enzyme respond better to alkylating agents like TMZ. Doctors measure this as MGMT promoter methylation: if the promoter is methylated, the gene is silenced, and the tumor is more likely to respond to treatment (2).

Christina’s tumor tested MGMT-methylated, predicting a good response to TMZ (9). For tumors without this methylation, chemotherapy may be less effective, and the benefits must be weighed against toxicity.

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How TMZ Works (Simplified)

• Goal: Damage tumor DNA so the cancer cell cannot replicate.

• Challenge: MGMT may repair the damage, making chemotherapy less effective.

• Predictive test: MGMT promoter methylation tells doctors whether TMZ is likely to work.

By understanding MGMT, researchers can personalize treatment and improve the chances of success, even if only slightly.

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Could I Have Done More?

The hard truth is that, for Christina, there was nothing more I could have done. But I refuse to believe the fight is over for others.

In future posts, I want to explore MGMT inhibitors (4), what we know about them, and some ideas that might make current treatments more effective. Could we intervene earlier—targeting the MGMT promoter rather than the enzyme itself? Perhaps that’s part of what alkylating agents are already doing.

This journey is both personal and scientific. I will continue to research, reflect, and share, because I refuse to accept that this is the end for people like Christina.

References:

1. Mechanisms of temozolomide resistance in glioblastoma - a comprehensive review
2. Methylguanine-DNA methyltransferase (MGMT)
3. Temozolomide Approval
4. MGMT Inhibitors
5. Chemotherapeutic Approaches for Targeting Cell Death Pathways
6. Difference Between Necrosis and Apoptosis
7. DNA Damage & Repair: Mechanisms for Maintaining DNA Integrity
8. The Structure of DNA
9. Methylguanine Methyltransferase Testing in Glioblastoma: When and How?
10. How Bevacizumab works as Anti-angiogenic therapy
11. Genes And Chromosones
12. Promoter