Podcast Summary: Tomorrow’s Cure — "The Quiet Beginnings of Leukemia"
Host: Kathy Werzer (Mayo Clinic)
Guests: Dr. Samir Parikh, Dr. Susan Slager, Dr. Gerald Marty
Date: March 4, 2026

Episode Overview

This episode explores the early stages and detection of chronic lymphocytic leukemia (CLL), focusing on its precursor, monoclonal B cell lymphocytosis (MBL). Through discussions with leading Mayo Clinic experts, the episode outlines the genetic and environmental factors driving these conditions, the advent of polygenic risk scoring, ethical considerations in early detection, and the transformative role of AI and population-level screening. The guests share both the science and patient perspectives, examining how advances in technology and a better understanding of the immune microenvironment are reshaping the future of leukemia prevention and care.

Key Discussion Points & Insights

1. The Discovery & Definition of MBL

• The Origin Story ([02:07])
  • Dr. Marty recalls the 1997 discovery with Dr. Robert Vogt during studies of people exposed to toxic Superfund sites. Findings of three individuals with increased B cells resembling CLL led to identifying early-stage CLL, named "monoclonal B cell lymphocytosis" (MBL).
    • Notable Quote:
      “We didn’t want to make a mistake. So, as I recall, at one point, we actually used three different sets of commercial reagents for kappa and lambda to be sure we got it right. It worked out perfectly.” – Dr. Gerald Marty [03:06]
  • First familial cases established, with observations that both environmental and familial factors may play roles.

2. Genetic & Environmental Risk Factors

• Why Do B Cells “Go Bad”? ([04:27])

  • The etiology of CLL/MBL is complex and multifactorial — no single risk factor stands out.
    • Notable Quote:
      “There isn’t clearly one sort of risk factor. So it isn’t only genetics. It’s not only environmental, because we’ve seen patients who are farmers in Iowa… and we have seen people who live in Manhattan who’ve never lived anywhere else who develop CLL." – Dr. Samir Parikh [04:36]
  • High prevalence of familial forms suggests a significant genetic component (Dr. Slager [05:56]).

• Prevalence and Implications of MBL ([07:51])

  • MBL is surprisingly common—affecting 8–10 million adults over 40 in the US. Initially thought to be a simple aging phenomenon, it’s now linked to heightened risk for CLL and other illnesses.
    • Notable Quote:
      “At first we just thought it was an aging phenomenon…Working with Dr. Parikh and Dr. Marty, we realized that having MBL increases your risk of other conditions, not only with CLL. It’s not just something you get with old age.” – Dr. Susan Slager [08:01]

3. Genomic Testing & Polygenic Risk Scores

• Risk Assessment Advances ([10:05])

  • Polygenic risk scores now aggregate 42 known CLL risk variants to quantify individual risk – highest scoring individuals show a nearly fourfold increased risk for CLL.
    • Notable Quote:
      “If you are at the high end of this distribution…you have almost a fourfold increased risk of developing CLL. If you’re at the low end, you’re actually protective.” – Dr. Susan Slager [10:15–11:25]

• Distinct “Flavors” of MBL ([12:14])

  • Important distinction between low count (population-level, rarely clinically detected) and high count MBL (often escalates to clinical attention and higher progression risk).

• Surveillance Strategies ([14:25])

  • Both groups may be subject to “watchful waiting,” but intensity and necessity differ. High count MBL patients are risk-stratified for regular monitoring.

    • Notable Quote:
      “Watch and wait becomes watch and worry, unfortunately, for a lot of people.” – Dr. Samir Parikh [14:25]

4. Clinical Complications and Overlapping Risks

• Risks Beyond Leukemia ([15:59])

  • MBL/CLL patients not only face risk of progression but are more prone to infections and secondary primary tumors.
    • Notable Quote:
      “There are two things…that are more clinical…One is the increase in infections…and also the increase in second primary tumors. Both of those are well-known characteristics of CLL.” – Dr. Gerald Marty [15:59]

• Genetic Overlap with Other Cancers ([17:30])

  • Shared genetic variants across lymphoma subtypes, myeloma, and melanoma suggest interconnected risks.

5. Artificial Intelligence & Technology’s Promise

• AI in Analysis & Diagnosis ([19:41], [20:57])

  • AI holds promise for:
    • Interpreting genetic variants of unknown significance.
    • Automating and accelerating flow cytometry, which currently restricts large-scale MBL detection.
      • Notable Quote:
        “AI can accomplish that [flow cytometric analysis]…in the length of time that you cough.”—Dr. Gerald Marty [21:07]
    • Training models to visually distinguish CLL lymphocytes from reactive ones, possibly reducing the need for costly flow cytometry ([22:54]).

• AI for Early Detection and Ethical Considerations ([25:42])

  • Early, equitable access is limited by expense, the labor intensiveness of current testing, and the need for specialized biospecimens.
  • Mass screening not currently recommended; ethical dilemmas exist in informing healthy individuals of increased risk with no clear intervention.

6. Population Research and the Pre-Cure Initiative

• Cohort Studies and Screening ([28:19])

  • Large scale studies at Mayo Clinic harness linked medical records and biospecimen banks for deep epidemiological insight and future risk modeling.

• Ethics of Risk Disclosure ([28:19])

  • Informing people with low count MBL remains contentious:
    • “The counterbalance is…if you tell them, they’re going to ask, well, what do I do about it?…For skin cancers, it’s already well known to wear sunscreen or wear clothing…for your clone, your MBL clone, growing…we don’t know how to stop it.” – Dr. Susan Slager [28:19]

• Pre-Cure Initiative and Hematology Precursor Clinic ([38:08])

  • Mayo Clinic’s Pre-Cure program provides a referral pathway for individuals with early hematologic abnormalities, aiming to personalize monitoring and support, and potentially intervene with lifestyle or immune-directed strategies.
    • Notable Quote:
      “We now have a special clinic called the Hematology Precursor Clinic where patients could be referred and have all of these additional testing…to try and better understand the risk of disease progression.” – Dr. Samir Parikh [38:08]

7. What Excites the Experts About the Future

• Microenvironment Matters ([30:57])

  • Research is shifting from just eradicating abnormal B cells to modifying the immune microenvironment — through structured exercise, diet, and perhaps targeted therapies — to prevent disease progression and complications.
    • Notable Quote:
      “It’s the immune milieu…the immune microenvironment around it…altering it at a very early stage might actually prevent some of these immune related complications that are a far bigger risk.” – Dr. Samir Parikh [30:57]
  • Dr. Marty points to the potential of early liquid biopsies, circulating tumor DNA, and AI-enhanced imaging as new frontiers ([34:32], [36:32]).

• Flagship Biomarkers and AI-enhanced Imaging ([36:32])

  • New biomarkers (clonal hematopoiesis, ctDNA) are being studied to sharpen who is genuinely at risk.
  • AI may be used to interpret radiology for early nodal involvement.

8. Emotional and Clinical Challenges

• Patient Anxiety in Early Detection ([40:04])

  • Being told of silent, currently untreatable risk can cause distress. The field is balancing the benefits of early knowledge with potential emotional harm, especially as therapies are not yet available for low-risk individuals.

    • Notable Quote:
      “Some of the CLL patients have talked to me saying, why did you tell me I have CLL when I’m not getting treated. And so MBL is even in an earlier stage.” – Dr. Susan Slager [40:25]

• Vision for the Next Decade ([41:02])

  • Dr. Marty advocates for honing in on the "cell of origin" and using a growing palette of targeted drugs—aiming for precise identification of those MBL patients who will inescapably progress.

    • Notable Quote:
      “… If we could define…those individuals with MBL that are definitely going to progress, I have…” – Dr. Gerald Marty [41:02]

Memorable Quotes

• “Watch and wait becomes watch and worry, unfortunately, for a lot of people.” – Dr. Samir Parikh [14:25]
• “If you are at the high end of this [risk] distribution…you have almost a fourfold increased risk of developing CLL.” – Dr. Susan Slager [10:15]
• “AI can accomplish [flow cytometry analysis] in the length of time that you cough.” – Dr. Gerald Marty [21:07]
• “It’s the immune milieu…altering it at a very early stage might actually prevent some of these immune related complications that are a far bigger risk.” – Dr. Samir Parikh [30:57]
• “Why did you tell me I have CLL when I’m not getting treated. And so MBL is even in an earlier stage.” – Dr. Susan Slager [40:25]

Key Timestamps

• [02:07] — Dr. Marty recounts the discovery of MBL
• [04:36] — Discussion on multifactorial origins of CLL/MBL
• [07:51] — Prevalence of MBL in adults over 40
• [10:15] — Polygenic risk scores explained
• [12:14] — Differentiating low vs. high count MBL
• [14:25] — Emotional burden of “watchful waiting”
• [15:59] — MBL’s risk for infections and secondary tumors
• [17:30] — Overlapping genetic risks with other cancers
• [19:41] — AI and machine learning potentials
• [21:07], [22:54] — AI transforming diagnostic imaging/flow cytometry
• [28:19] — Ethics of mass MBL screening
• [30:57] — Immune environment as therapeutic target
• [34:32] — Survival rates in CLL and new frontiers in early detection
• [36:32] — AI in radiology and nodal MBL
• [38:08] — Mayo Clinic’s Pre-Cure Initiative
• [40:25] — Emotional quandaries for early-stage patients
• [41:02] — Dr. Marty’s hopes for the next 5-10 years

Conclusion

This episode demonstrates how the boundaries of cancer prevention and early intervention are moving, with MBL serving as a window into the earliest stages of leukemia risk. The intersection of genetics, environment, cutting-edge diagnostics, and artificial intelligence is opening new avenues for both understanding and managing silent disease. However, as healthcare innovation accelerates, the field must grapple with complex ethical, emotional, and societal questions—not just scientific ones. As Dr. Marty summarizes, the next decade is likely to focus on refining risk prediction and tailoring interventions to truly alter the course of this quietly beginning, but potentially severe, disease.