JAK2 Mutation - Effects and Questions

My father passed away from a battle of myelofibrosis (MF), over 10 years after being diagnosed with enlarged spleen and 6 from diagnosis of MF. I am nearly 9 months post immunotherapy treatment for stage 3 melanoma treatment (discovered in lymph nodes without known source). During a post treatment CT scan the radiologist identified my enlarged spleen, which is not typical of melanoma, but could be a side effect of immunotherapy (very rare and limited literature). My oncologist was dismissive of the genetic potential for me to have MF, like my father. Additional observation of my spleen showed continued growth and my oncologist finally discussed with another who suggested a JAK2 mutation blood test. You can see where this is headed; I was notified yesterday that I have the JAK2 gene mutation. I am 47. I am in good health; other than previous melanoma (nearly 2 years from discovery) that I have battled and praying for a very good prognosis on that front shortly! My melanoma specialist is being reassigned and I will be headed to another hematologist that is very familiar with my family history of cancer. As my medical group sends test results directly to the patient as soon as they are received I have yet to discuss with my Dr. I presume I will have a bone marrow biopsy to determine stage, if any, at this point. I am jumping to the MF diagnose myself; treatments for early stage, ongoing studies or any suggestions to extend this wonderful life are appreciated. As with melanoma, the treatments are expanding by the day, I will not hang my head in fear, but give this godforsaken disease a damn good fight. Too much to live for to live in fear.

My early Thanksgiving treat was finding out that I in fact have MF. Ugh. Interestingly, my spleen has decreased in size 18% and I have almost no blood numbers that are concerning. My platelets typically are over 450k, but almost always below 600k; elevated, but as some of you have mentioned this is not an alarming amount. However, the bone marrow biopsy did show elevated numbers in several measurements that are indicators of MF; the marrow itself had some but limited fibrosis. Dr. ordered the genetic testing on the bone marrow. That biopsy is a doozy! Might have let out a bit of "french" for the PA to hear... oops. Though there is not a grading level for MF, like in other cancers, my range is MF 0-1. It is early in the fight. Trying to wrap my mind around what this means for the near term as I have seen firsthand what the end of this can look like with my father. I am trying to focus on one day at a time.

Hello @ettap and welcome to Connect. It is good to see that you have confirmed your mutation twice, but are not currently experiencing any of the symptoms. If you don't mind, I am going to give a couple of quick resources in regard to a few of your questions:

- Polycythemia vera treatment: https://www.mayoclinic.org/diseases-conditions/polycythemia-vera/diagnosis-treatment/drc-20355855
- Essential thrombocytosis: https://www.mayoclinic.org/diseases-conditions/essential-thrombocythemia/diagnosis-treatment/drc-20361131

This is also from Mayo Clinic, "The mutation that causes polycythemia vera is thought to affect a protein switch that tells the cells to grow. Specifically, it's a mutation in the protein Janus kinase 2 (JAK2). Most people with polycythemia vera have this mutation. The cause of the mutation isn't known, but it's generally not inherited. Polycythemia vera can occur at any age, but it's more common in adults older than 60."

@ettap, if you don't mind sharing, have those three specific hematological disorders been discussed with you by your hematologist? Has he or she mentioned myelofibrosis? I am not a medical professional and am in no way diagnosing, but myelofibrosis can be a result of a JAK2 mutation as well.

I met with new oncologist/hema this week. I will be getting a bone marrow biopsy, as expected, to determine the amount of fibrosis. Dr. was a bit optimistic that my CBC was not presenting evidence of MF. Other than a slightly elevated platelet count they are fairly stable and within margins each test. The enlarged spleen does not signify MF by itself. The JAK2 mutation is not hereditary, but the cause of it may be, not enough data on the subject to know what causes the mutation. It appears that this was caught early and potentially prior to the MPN presenting. Will know more after the biopsy. Be well.

I met with new oncologist/hema this week. I will be getting a bone marrow biopsy, as expected, to determine the amount of fibrosis. Dr. was a bit optimistic that my CBC was not presenting evidence of MF. Other than a slightly elevated platelet count they are fairly stable and within margins each test. The enlarged spleen does not signify MF by itself. The JAK2 mutation is not hereditary, but the cause of it may be, not enough data on the subject to know what causes the mutation. It appears that this was caught early and potentially prior to the MPN presenting. Will know more after the biopsy. Be well.

Scott, when do you meet with the hematologist? I’ll be interested to hear about his/her suggestions.

I believe my oncologist, a melanoma specialist, was only concerned with the melanoma and did not look at the potential for other cancers to be present or beginning to present. I had discussed with family changing oncologists, but felt it was important to see the melanoma treatment through. His theory, which is typical, is that JAK2 nor MF are hereditary and should not be a concern. May not have MF yet, but having enlarged spleen and JAK2 along with a few other symptoms.... Unfortunately, cures and full treatments are not in place for MF. The only "cure" is a replacement of bone marrow unless something else comes down the line.

@scottmatteo Go for it, Scott. I know what it is to have MF diagnosed, then ignored by Mayo (Phoenix). I do not know what one should do to treat this killer, but it is a shame that it is ignored. Do all clinics ignore it this way?