------
## 最终结论
```python
import re

def remove_lowercase(s):
    return re.sub(r'[a-z]', '', s)

# Test cases
assert remove_lowercase('KDeoALOklOOHserfLoAJSIskdsf') == 'KDALOOOHLAJSI'
assert remove_lowercase('ProducTnamEstreAmIngMediAplAYer') == 'PTEAIMAAY'
assert remove_lowercase('maNufacTuredbYSheZenTechNolOGIes') == 'NTYSZTNOGI'
```