overexpression

noun

over·​ex·​pres·​sion -rik-ˈspresh-ən 

: excessive expression of a gene (as that caused by increasing the frequency of transcription)

We now suspect that many, if not most, cancers arise through the overexpression … of key cellular regulatory genes

—J. D. Watson et al.

overexpress

-rik-ˈspres 

transitive verb