I probably should know more about this than I do, but I haven't actually read up all that much on it as I don't want to become obcessive about my disease. Believe me, that's an easy trap to fall into when you work in science for a living. You know just enough to get your worried, but not enough about that particular discipline to make you stop worrying! Very easy to overinterpret when you know too much. Hence the reason I don't dig into these things very often. Not a good idea for me to get to "into it".
I will ask some more questions, but here is what I do know. A biopsy is a "snapshot" of your disease, nothing more. Yes, it will depend on the sampling method, at what stage your disease is at the time of the "snapshot", the preparation of the sample, and finally, the huge variable of the interpretation of the person reading the slides and interpreting the information.
As Joan says above, the ckit is often present in masto patients (but not all) and they also look at how many activated mast cells are in the bone marrow. To tell if they are activated, they run other tests on them using a flow cytometry technique. Basically, they stain your cells with a stains that may recognize specific "markers" or proteins on your cells. One of these is CD25, which is a marker for this, another one they sometimes look at is CD117(this is just a marker for mast cells, doesn't tell you necessarily whether they are "good" or "bad", just tells you that you are actually looking at a mast cell). So you see, first, they have to identify the mast cells themselves. Another component of this process is to do a preparation of your biopsy on a slide and place it in the microscope. They use stains for this as well. The "bad" mast cells have a certain "morphology" or "appearance", and their are certain criteria for examining under the microscroscope. At different stages of division, activation, or abnormality, cells can appear different, and it is this appearance that also is used in classifying your condition.
So, as you can tell already from just this description, it is important to have somebody who is familiar with the disease take a look at all of this as they are used to seeing it and are familiar with how it looks.
And, as Joan says, it also depends on whether there is involvment of other organs and blood components. Yes, the CBC is a good indicator of whether other blood components are involved, which requires a different therapeutic approach. This is also why they often run liver tests also, as the liver can be involved as well if it starts to bother your other organs. So often, you will get a tryptase, CBC, and liver panel run when you have your checkups. They are getting another "snapshot" of your condition.
I was intitially diagnosed with this at the very earliest stages of the disease, only two months after I developed symptoms of it. Probably, more early than most of you. I was fortunate enough to get connected with an intake doc at Mayo who had a patient with this before, got straightaway connected with Dr.s Akin and Butterfield. I work in science and was familiar with what places to go to get good dianostics. I had very few activated cells, with only a modestly elevated tryptase. I met a couple of the minor criteria.
Since it has been so many years since my early "snapshot" I would not be surprised to see changes. And, as Sandi points out, the information about it has changed much since then. The markers that they look for can have information of some value, but it depends very much on the individual patient's presentation. One thing is for sure, we masto patients are all quite unique, which makes this disease a very challenging one to manage.
With the advent of new technology in molecular medicine, new medications are being developed that target specific genetic abnormalities in cells. This is a new line of targeted therapy that has been successful in treating some cancers. For example, the drug Gleevec (Imatinib) was developed to treat some types of blood cancer cells that have a specific mutation. As these drugs are developed, there may be "crossover" with other types of neoplasms that have the same genetic error or "mutation."
Whether or not a person would benefit from this type of therapy depends on several important factors. First, they need to have that kind of mutation, then, it would depend on whether or not they are managing the disease o.k. without the therapy, how many "bad" cells they have, whether or not they are affecting other organs, and whether the drug would really help get rid of it, or just hold it at bay as a "bandaid." The side effects of the drug or possible unknown bad effects would have to be balanced against the severity of the disease. And, for most people, masto won't actually kill you. As one hematologist aptly put it for me "Don't think of this as a cancer. It probably won't actually kill you, but it can make you awful miserable."
So, in my case, we are trying to figure out if this is just a "flare up" where the cells are behaving badly, or if the cells have changed somehow, or if there are just more of the little guys in the body right now who have decided to throw a "hissy-fit" and fire off. This is kind of the umbrella of uncertainty we all live under, but that's the way it is.
Get's old doesn't it?