Thanks for your response, James. As far as I am aware from research I was involved in sideways heat shock proteins, HSP70 being a dominant one, are produced temporarily in all kinds of organisms, including humans, as a result from stress (such as heat exposure) and their function has been related to relieving the stress that triggers their production. HSP production drops back gradually after the stress factor has been removed. So you are correct to be cautious, it is not a mutation, it is merely a temporary conditional expression.
I am convinced HSP are are not something to worry about.