my understanding is you have to keep in the same field. if your I140 is NIW, you can not say you work as a pharmacist after you get your ead. the person from bio- to phy- can not say s/he does clinical work after s/he gets ead because clinical -- belong to another one in gc application.
before you would like to try, you have to find a way to reply any possible ref, for example, bio~ and phy~ both on cancer research, clinical cancer research is a good one...
good luck,
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