'abnormally-expressed' originates from the combination of 'abnormal' and 'expressed', where 'abnormal' means 'deviating from the normal or usual' and 'expressed' refers to the manifestation of a gene or protein.

'Abnormally-expressed' combines the words 'abnormal' and 'expressed', which have been used in scientific contexts to describe gene expression levels.

Initially, it meant 'expressed in an unusual manner', and this meaning has largely remained the same in modern scientific usage.