The Classic Myeloproliferative Neoplasms
Optimizing Laboratory Testing for Hematologic Disorders Series
JAK2 Exon 12 Sequencing Background
October 2011
Now I would like to give you some background information regarding the JAK2 exon 12 sequencing assay. Approximately 5% of PVs will be JAK2 V617F-negative, but will have an identifiable novel mutation in exons 12 to 14 of the JAK2 gene that can be identified only by sequencing studies. Thus, it appears that virtually all cases of PV will have some type of a JAK2 mutation. JAK2 exon 12 to 14 mutations are either felt to be absent or extremely rare in patients with ET or PMF. At Mayo Clinic, we have never seen a bona fide ET or PMF with a JAK2 exon 12 mutation. Remember, sequencing studies will also identify the JAK2 V617F mutation, which is in exon 14. But sequencing is more expensive, takes longer to get results, ie, a slower turnaround time, and is certainly less sensitive than RT-PCR, having a detection level of approximately 10%–20% versus PCR, which has a detection level of much less than 0.01%.
JAK2 Exon 12 Sequencing Background |
Jump to section:
- Introduction
- Optimizing Laboratory Testing for Hematologic Disorders Series
- Goals for Today's Presentation
- Example of a Recent MPN Referral
- Why Do We Have Test Utilization Issues?
- Why Do We Have Test Utilization Issues?
- So What Should We Do?
- WHO Classification
- Important Laboratory Assays in the MPNs
- JAK2 V617F Background
- JAK2 V617F Background
- Question #1 — JAK2 V617F
- JAK2 V617F
- JAK2 V617F at Mayo Clinic
- Conclusion #1 — JAK2 V617F
- JAK2 Exon 12 Sequencing Background
- Question #2 — JAK2 Exon 12 Sequencing
- JAK2 Exon 12 Sequencing: When Not to Use
- JAK2 Exon 12 Sequencing
- Conclusion #2 — JAK2 Exon 12 Sequencing
- MPL Exon 10 Sequencing Studies: Background
- Question #3 — MPL Exon 10 Sequencing
- MPL Exon 10 Sequencing: When to Use
- MPL Exon 10 Sequencing: When Not to Use
- MPL Exon 10 Sequencing
- Conclusion #3 — MPL Exon 10 Sequencing
- Roles of Other Assays in Classic MPN
- Summary
- Myeloproliferative Neoplasm: A Diagnostic Approach to Peripheral Blood Evaluation
- Myeloproliferative Neoplasm: A Diagnostic Approach to Bone Marrow Evaluation
- Implementing a Utilization Approach
- Questions


