As a cholesterol analog, 4-cholesten-3-one (4-en-3-one) can increase membrane fluidity by displacing membrane cholesterol, leading to translocation of membrane molecules, such as CD44 shedding.5 Given that cholesterol functions as a membrane adhension molecule and contributes to tumor invasion and metastasis,5 it was hypothesized that 4-en-3-one might interfere with tumor invasion and metastasis by substituting membrane cholesterol. Here, CD44 is linked to neoplasm.