CDK5 and pituitary gland adenoma: Cytoplasmic p35 staining was significantly higher in noninvasive prolactin pituitary adenomas (mean H-score: 175) than in normal pituitary tissue (mean H-score: 142), with the highest expression observed in invasive prolactin pituitary adenomas (mean H-score: 212, Figure 2A, 2B), whereas no significant differences were detected in CDK5 H-scores.