Plucked Human Hair as a Tissue to Assess Pharmacodynamic Endpoints During Drug Development Studies

The study demonstrated the feasibility of using plucked human scalp and eyebrow hair to detect and quantify six cell-cycle-related nuclear markers, including Ki67, pRb, p27, phospho-p27, phospho-pRb, and phospho-HH3. It provided estimates of the proportion of hairs lost or damaged during processing and assessed the intra- and intersubject variability of each marker. These findings were intended to guide the design of future drug intervention studies targeting these markers.