> For the complete documentation index, see [llms.txt](https://www.brexatlas.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://www.brexatlas.org/bre-001/bre-003.md). # BRE 003 ## Electric Fields, Radiation, and DNA Repair in Brain Cancer **Clinical Cancer Name:** Glioma / Glioblastoma **Common Cancer Name:** Brain Cancer **Source** Giladi, M., Munster, M., Schneiderman, R. S., Voloshin, T., Porat, Y., Blat, R., Zielinska-Chomej, K., Hååg, P., Bomzon, Z., Kirson, E. D., Weinberg, U., Viktorsson, K., Lewensohn, R., & Palti, Y. (2017). Tumor treating fields (TTFields) delay DNA damage repair following radiation treatment of glioma cells. *Radiation Oncology, 12*(1), 206. *** ## BRE-003 Scoring Section ### BRS Score **BRS: 8.2 / 10**\ **STEMD:** S8 / T8 / E8 / M9 / D8\ **External Evidence Level:** Moderate–High in-vitro TTFields + radiation mechanism evidence ### Score Interpretation BRE-003 receives a strong score because it expands TTFields beyond mitotic disruption into DNA damage repair delay after radiation exposure. Its major contribution is showing that TTFields may increase radiation vulnerability by interfering with repair processes in glioma/glioblastoma systems. *** ## Entry Summary BRE-003 asks a new question in the BREXAtlas Encyclopedia: Can electric fields make radiation treatment more effective? This study focused on brain cancer cells and examined what happened when Tumor Treating Fields were used after radiation therapy. Radiation works partly by damaging cancer-cell DNA. If a cancer cell repairs that damage, it may survive. If repair is delayed or disrupted, the cancer cell may become more vulnerable. BREXAtlas identifies BRE-003 as an important mechanism-expansion entry because it suggests TTFields may do more than interfere with cell division. They may also affect how cancer cells respond to DNA damage. ***
Can electric fields help radiation work better? What BREXAtlas found: Yes, in this in-vitro brain cancer study, TTFields enhanced the effect of radiation treatment in glioma cells. The study found that when TTFields were applied after radiation, cancer cells showed delayed DNA damage repair and increased persistence of DNA damage markers. In everyday language, radiation damaged the cancer cells, and TTFields appeared to make it harder for those cells to recover. What still needs more research: This was a laboratory cell study. More research is needed to determine how this effect translates across tumor types, patient tumors, and clinical treatment schedules.
***
Is TTFields only about stopping cell division? What BREXAtlas found: No. BRE-001 and BRE-002 emphasized cell division and frequency optimization. BRE-003 expands the picture. This study suggests TTFields may also affect DNA repair pathways after radiation. That matters because cancer survival is not only about how fast cells divide. It is also about how well cancer cells repair damage and adapt to treatment stress.
*** ## What cancer cells were studied? BRE-003 studied glioma cell lines, which are laboratory models of brain cancer. | Cell Line | Cancer Type | | --------- | --------------------- | | U-118 MG | Glioma / Brain Cancer | | LN-18 | Glioma / Brain Cancer | *** ## Treatment Parameters | Parameter | BREXAtlas Extraction | | ------------------------ | ------------------------------------ | | Treatment Type | Tumor Treating Fields plus radiation | | Frequency | 200 kHz | | U-118 MG Field Intensity | 1.75 V/cm RMS | | LN-18 Field Intensity | 1.0 V/cm RMS | | TTFields Duration | 72 hours | | Radiation Doses Tested | 0.5, 1, 2, 4, 6, and 8 Gy | ***
Does the timing of electric-field treatment matter? What BREXAtlas found: The study tested TTFields beginning at different times after radiation: * Immediately after radiation * 1 hour after radiation * 4 hours after radiation * 24 hours after radiation This makes BRE-003 important because it introduces treatment timing as a variable. The question is not only: Should electric fields be used? It is also: When should they be used?
*** ## Observed Responses BREXAtlas extracted the following main responses: * TTFields enhanced radiation effectiveness. * DNA damage repair was delayed. * DNA damage markers remained longer. * γH2AX foci retention increased. * Rad51 foci formation increased. * Homologous recombination repair appeared involved. In simple terms, the cancer cells showed signs that DNA damage lasted longer after TTFields were combined with radiation. *** ## Quantitative Findings ### U-118 MG Cell Line | Radiation Dose | Surviving Fraction with TTFields + Radiation | | -------------- | -------------------------------------------- | | 2 Gy | 0.292 | | 4 Gy | 0.169 | | 6 Gy | 0.061 | | 8 Gy | 0.021 | ### LN-18 Cell Line | Radiation Dose | Surviving Fraction with TTFields + Radiation | | -------------- | -------------------------------------------- | | 2 Gy | 0.025 | | 4 Gy | 0.005 | | 6 Gy | 0.001 | | 8 Gy | 0.000 | These results suggest that the combination of TTFields and radiation produced strong effects in the tested glioma cell lines. *** ## Mechanisms ### MEC-004: DNA Repair Interference BRE-003 supports the idea that TTFields may interfere with the cancer cell’s ability to repair radiation-induced DNA damage. ### MEC-005: Radiosensitization Radiosensitization means making cancer cells more sensitive to radiation. BRE-003 suggests TTFields may act as a radiosensitizing intervention in glioma cells. ### MEC-006: Homologous Recombination Pathway Involvement The study points toward DNA repair pathway involvement, including homologous recombination-related activity. In everyday language, TTFields may affect the repair system cancer cells use after radiation injury. *** ## What BREXAtlas Found BREXAtlas classifies BRE-003 as a mechanism-expansion entry. It moves the encyclopedia beyond the first two questions: * BRE-001: Can electric fields affect cancer cells? * BRE-002: What frequency works best? BRE-003 asks: Can electric fields make existing cancer treatments more effective? The answer from this study is promising but still requires further validation. *** ## Public Source Validation Public TTFields literature recognizes that alternating electric-field therapy may affect more than mitosis alone, including DNA repair and treatment-combination biology. BRE-003 fits that public understanding because it directly studies TTFields combined with radiation in glioma cells. BREXAtlas does not treat this as proof that TTFields will improve all radiation therapy. Instead, BREXAtlas classifies it as evidence that TTFields may interfere with DNA repair in specific brain cancer cell models. *** ## Connections to Other BRE Entries ### Connected to BRE-001 **Connection:** BRE-001 introduced TTFields as a treatment that disrupts cancer cell proliferation and mitosis. **How BRE-003 expands it:** BRE-003 suggests TTFields may also interfere with DNA repair after radiation. Read BRE-001 for: foundational TTFields evidence and mitotic disruption. *** ### Connected to BRE-002 **Connection:** BRE-002 focused on frequency optimization. **How BRE-003 expands it:** BRE-003 uses 200 kHz in glioma cells, reinforcing 200 kHz as an important frequency in early brain cancer TTFields research. Read BRE-002 for: frequency selection and optimization. *** ### Connected to BRE-004 **Connection:** BRE-003 points toward mechanism expansion beyond mitosis. **Expected relationship:** BRE-004 should be reviewed for additional TTFields mechanism evidence and whether it supports, refines, or challenges the DNA-repair pathway connection. *** ### Connected to Future Combination Therapy Entries **Connection:** BRE-003 is an early combination-therapy entry because it studies TTFields with radiation. Future entries involving chemotherapy, radiation, targeted therapy, or immunotherapy should be compared against BRE-003 to determine whether TTFields consistently enhance other treatments. *** ## Research Gaps Identified * **RG-011: Radiation Combination Gap**\ Can TTFields reliably improve radiation response across more glioma models and patient-derived samples? * **RG-012: Timing Gap**\ What is the best time to begin TTFields after radiation? * **RG-013: DNA Repair Pathway Gap**\ Which DNA repair pathways are most affected by TTFields? * **RG-014: Clinical Translation Gap**\ Do these laboratory findings translate into meaningful patient outcomes? * **RG-015: Cross-Cancer Combination Gap**\ Does TTFields radiosensitization apply only to glioma, or can it extend to other cancers? *** ## Why This Entry Matters For scientists, BRE-003 adds a major mechanism question: TTFields may not only disrupt cell division but may also affect DNA repair after radiation. For patients and families, the practical meaning is easier to understand: Cancer treatments often work better when cancer cells cannot recover from damage. BRE-003 suggests TTFields may help make brain cancer cells less able to repair radiation damage. This does not replace radiation. Instead, it raises the possibility that electric fields could one day help radiation work more effectively in selected cancers. *** ## Entry Conclusion BRE-003 is a key transition entry in the BREXAtlas Encyclopedia. BRE-001 showed that electric fields can affect cancer growth. BRE-002 showed that frequency matters. BRE-003 shows that electric fields may also interact with other cancer treatments, especially radiation. This makes BRE-003 important because it shifts the encyclopedia from single-treatment response toward combination-treatment strategy. The central question emerging from BRE-003 is: Can bioelectric therapy make cancer cells more vulnerable to treatments they already receive? 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