According to Gram Research analysis, folate receptor alpha expression in ovarian cancer remains stable in approximately 77% of patients over time, but changes in about 23% of cases. A Mayo Clinic study of 66 ovarian cancer patients found that when changes do occur, tumors are more likely to gain the marker (16.7% of cases) than lose it (6.1%), suggesting that cancer biology can evolve during disease progression. This means the marker is generally reliable for guiding treatment decisions, though doctors should consider repeat testing if cancer progresses.
Researchers at Mayo Clinic studied how a specific protein marker called folate receptor alpha changes in ovarian cancer patients over time. This marker is important because doctors use it to decide which patients might benefit from a newer cancer drug called mirvetuximab soravtansine. The study looked at 66 patients with ovarian cancer who had multiple tumor samples taken at different times. They found that the marker stayed the same in about 77% of cases, but changed in about 23% of cases. This helps doctors understand that while the marker is usually reliable for treatment decisions, they should be aware that it can sometimes change, especially in patients receiving certain types of chemotherapy.
Key Statistics
A 2026 single-institution study of 66 ovarian cancer patients found that folate receptor alpha expression remained concordant in 77.3% of paired tumor specimens, indicating the marker is generally stable over time.
Among 66 ovarian cancer patients studied at Mayo Clinic Florida between 2013 and 2025, negative-to-positive conversion of folate receptor alpha occurred in 16.7% of cases compared to positive-to-negative conversion in only 6.1%, suggesting tumors may develop increased marker expression as they progress.
In ovarian cancer patients receiving neoadjuvant chemotherapy, negative-to-positive conversion of folate receptor alpha occurred in 25% of cases versus 9% in other treatment settings, though this difference was not statistically significant in the 66-patient Mayo Clinic study.
The Quick Take
- What they studied: Whether a protein marker used to guide ovarian cancer treatment stays the same or changes when doctors take new tumor samples from the same patient over time.
- Who participated: 66 ovarian cancer patients (average age 66 years) treated at Mayo Clinic Florida between 2013 and 2025. Most had advanced-stage high-grade serous carcinoma, which is the most common and aggressive type of ovarian cancer.
- Key finding: The folate receptor alpha marker stayed consistent in 77.3% of paired tumor samples, but changed in 22.7% of cases. When it did change, tumors were more likely to gain the marker (16.7% of cases) than lose it (6.1% of cases).
- What it means for you: If you have ovarian cancer and your doctor tests for this marker to decide on treatment, the result is usually reliable. However, your doctor should know that in about 1 in 5 cases, the marker can change over time, so repeat testing might be helpful if your cancer progresses or changes.
The Research Details
This was a retrospective study, meaning researchers looked back at medical records and tissue samples from patients already treated at Mayo Clinic Florida between 2013 and 2025. They included only patients who had at least two tumor samples collected at different times, either from initial diagnosis or from later treatments. The researchers examined these tissue samples under a microscope to check for the presence and amount of folate receptor alpha protein. They classified tumors as positive for the marker if at least 75% of cancer cells showed moderate-to-strong staining. They then compared the results from the first sample to the second sample to see if the marker status stayed the same (concordant) or changed (discordant).
The researchers used statistical tests to look for patterns. They checked whether certain patient factors like age, cancer stage, type of chemotherapy received, or time between samples might explain why some patients’ marker status changed while others’ stayed the same. They used Fisher exact tests and Kruskal-Wallis tests, which are standard statistical methods for comparing groups in medical research.
This approach is practical because it uses real patient data and actual tissue samples that were already collected as part of routine cancer care. However, because it’s retrospective, the researchers couldn’t control all the factors that might affect the results, such as exactly where on the tumor each sample was taken or how long patients waited between samples.
Understanding whether this marker stays stable over time is crucial for cancer treatment decisions. The folate receptor alpha marker is used to identify patients who might benefit from mirvetuximab soravtansine, an FDA-approved drug that specifically targets this protein. If the marker changes frequently, doctors would need to retest patients during treatment to make sure they’re still getting the right therapy. This study helps doctors know how often they should expect the marker to change and whether they need to repeat testing.
This study has several strengths: it uses real patient data from a major medical center, includes a reasonable number of patients (66), and examines actual tissue samples under standardized conditions. However, there are some limitations to consider. The study is retrospective, so researchers couldn’t control all variables. The sample size is moderate, which means some findings that appeared to show trends (like the higher conversion rate in patients receiving neoadjuvant chemotherapy) didn’t reach statistical significance. The study was conducted at a single institution, so results might differ in other hospitals or patient populations. Additionally, the study doesn’t explain why the marker changes in some cases, only that it does.
What the Results Show
Among the 66 ovarian cancer patients studied, 77.3% showed concordant folate receptor alpha expression, meaning the marker status stayed the same between their first and second tumor samples. This suggests the marker is generally stable and reliable for treatment planning. However, 22.7% of patients showed discordant results, meaning their marker status changed between samples.
When changes did occur, they followed a specific pattern: tumors were more likely to gain the marker than lose it. Specifically, 16.7% of patients converted from negative to positive (meaning the marker appeared in later samples when it wasn’t there before), while only 6.1% converted from positive to negative (meaning the marker disappeared). This pattern suggests that ovarian cancer tumors may develop new ways to express this protein as they progress or change in response to treatment.
The researchers looked for explanations for why some patients’ marker status changed while others’ remained stable. They examined many factors including patient age, cancer grade and stage, type of chemotherapy received, whether patients had received prior chemotherapy, whether they had been treated with mirvetuximab soravtansine, the type of tissue sample (like whether it came from surgery or biopsy), where on the tumor the sample was taken, the baseline marker expression level, and how much time passed between samples. Surprisingly, none of these factors showed a statistically significant association with marker changes.
One finding that approached but didn’t reach statistical significance was in patients who received neoadjuvant chemotherapy (chemotherapy given before surgery). In this group, negative-to-positive conversion occurred in 25% of cases compared to 9% in other treatment settings. While this difference wasn’t statistically significant (p = 0.479), it suggests a possible trend that chemotherapy might influence marker expression. This finding warrants further investigation in larger studies. The lack of association between specimen type (surgical samples versus biopsies) and marker concordance suggests that how the tissue was obtained doesn’t explain the variability.
This is one of the first studies to systematically examine how folate receptor alpha expression changes over time in ovarian cancer patients. Previous research established that this marker is frequently present in ovarian cancer and is important for treatment selection, but little was known about its stability. This study fills an important gap by showing that while the marker is generally stable (supporting its use in treatment decisions), clinicians should be aware that changes can occur in a meaningful minority of patients. The finding that negative-to-positive conversion is more common than positive-to-negative conversion is particularly important and suggests that tumor biology may evolve in ways that increase marker expression.
Several important limitations should be considered when interpreting these findings. First, this is a single-institution study from Mayo Clinic Florida, so results may not apply to all ovarian cancer patients or all hospitals. Second, the study is retrospective, meaning researchers worked with existing data and couldn’t control all variables that might affect results. Third, the sample size of 66 patients is moderate, which means some trends (like the higher conversion rate with neoadjuvant chemotherapy) didn’t reach statistical significance and might be due to chance. Fourth, the study doesn’t explain the biological reasons why marker status changes in some patients. Fifth, the timing between samples varied among patients, and the study couldn’t determine if longer time intervals were associated with more changes. Finally, the study doesn’t provide information about patient outcomes or whether marker changes affected treatment effectiveness or survival.
The Bottom Line
If you have ovarian cancer and your doctor recommends testing for folate receptor alpha to guide treatment decisions, this test is generally reliable based on this research. The marker stays consistent in about 3 out of 4 patients. However, if your cancer progresses or changes during treatment, your doctor may want to retest to confirm the marker status, especially if you’re considering mirvetuximab soravtansine or other targeted therapies. This is a moderate-confidence recommendation based on a single-institution study.
This research is most relevant to patients with advanced ovarian cancer, particularly high-grade serous carcinoma, who are being considered for mirvetuximab soravtansine or other folate receptor-targeted therapies. Oncologists and pathologists who test for this marker should be aware that changes can occur in about 1 in 5 patients. Patients receiving neoadjuvant chemotherapy may want to discuss with their doctors whether repeat marker testing would be helpful. This research is less relevant to patients with early-stage ovarian cancer or other cancer types.
The marker status can change at any point during a patient’s cancer journey, but this study doesn’t specify how quickly changes occur. Some changes may happen over months or years. If you’re starting a new treatment, your doctor might recommend retesting after several months to confirm the marker status remains appropriate for your current therapy.
Frequently Asked Questions
Does the folate receptor alpha marker stay the same in ovarian cancer patients over time?
Mostly yes. A 2026 Mayo Clinic study of 66 ovarian cancer patients found the marker remained stable in 77.3% of cases. However, it changed in about 23% of patients, so doctors may recommend repeat testing if cancer progresses or treatment changes.
What does it mean if my folate receptor alpha test result changes between samples?
Changes are relatively uncommon but can happen. When they do occur, tumors are more likely to gain the marker than lose it. This may reflect how cancer evolves during treatment. Your doctor can discuss what this means for your specific treatment options.
Should I get retested for folate receptor alpha during my ovarian cancer treatment?
This depends on your individual situation. If your cancer progresses or you’re considering a new targeted therapy like mirvetuximab soravtansine, discuss with your oncologist whether repeat testing would help guide treatment decisions, since the marker can change in some patients.
Is folate receptor alpha testing reliable for deciding on ovarian cancer treatment?
Yes, generally. The marker is stable in about 3 out of 4 patients, making it a reasonably reliable guide for treatment selection. However, the Mayo Clinic study shows that changes occur in approximately 1 in 5 cases, so your doctor may recommend confirming results if circumstances change.
Does chemotherapy affect folate receptor alpha expression in ovarian cancer?
A Mayo Clinic study found that patients receiving neoadjuvant chemotherapy showed a higher rate of negative-to-positive marker conversion (25% vs 9%), though this wasn’t statistically significant. More research is needed to understand chemotherapy’s effect on marker expression.
Want to Apply This Research?
- Track the dates and results of folate receptor alpha marker tests in your cancer care timeline. Record whether each test showed positive or negative results and note any changes in treatment recommendations based on test results.
- If your doctor recommends marker testing as part of your treatment planning, set reminders to discuss with your oncology team whether repeat testing is appropriate if your cancer progresses or if you’re starting a new treatment. Keep a record of all marker test results to share with your care team.
- Create a long-term log of all biomarker tests, treatment changes, and clinical outcomes. This personal record helps you and your medical team track patterns and make informed decisions about whether repeat testing is needed. Share this information with any new doctors who join your care team.
This article summarizes research findings and is not medical advice. Folate receptor alpha testing and treatment decisions should only be made in consultation with your oncology team. The stability of this marker may vary based on individual factors not covered in this study. If you have ovarian cancer, discuss with your doctor whether marker testing and repeat testing are appropriate for your specific situation. This research was conducted at a single institution and may not apply to all patient populations or healthcare settings.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.