noun stack

A noun stack, which can also be called a noun cluster or string, is when a group of nouns are used together. Usually, there is one true noun. The others might be used as adjectives; that is, they modify the noun.

名詞を重ねた形

We used a sensitive protein function monitoring system

The “real” noun is the last one, system. But what does the system do? Is it a sensitive system that monitors protein function? Or could it be a system that monitors sensitive proteins? From this sentence alone, we can’t say which is the correct meaning.