PIK3CA and gastric cancer: For PIK3CA, immunohistochemistry (IHC) detection in other solid lesions, the cut-off value describing positive samples was individually determined, e.g., in non-small cell lung cancer and colorectal cancer, the cut-off point was H-score ≥ 10 [31,54]; in stomach cancer it was for over 20% of stained cells [55].