@marcwall - Good question, and I don't mind. The first was when I was first diagnosed, the 2nd and 3rd were taken as symptom load was increasing and when I had issues related to HU. The remaining ones were for screening for clinical trials as required by the sponsor. Fourth, was a phase 1 trial that I ended up not qualifying for. Five, 6, 7, and 8 were for another trial screening; for this the sponsor required 2 biopsies and samples 5 and 6 were not good so had to repeat to make 7 and 8 (3 weeks later); I did get on that phase 3 trial but was the standard of care arm. Nine was to start a phase 1 trial that I started a bit over a month ago. And as long as I stay on this trial they will do biopsies every 3 months for several years (or something close to that as I understand).
The key ones were really the 1st and 3rd, and even if they looked at previous samples, they would not have caught the increase in VAF as it had increased to about 20% to over 50% in the last one (all in less than 10 years). In essence, were I not interested in participating in trials there would likely only have been 3.
Hope this helps (and now you know why, with "experience" one gets used to these and make sure that all know that lidocaine is really your friend). : )