MKI67 and neoplasm: This association was also significant when the Ki-67 proliferation index of HPV-positive samples (median: 71.0%, interquartile range: 16.0%) with nuclear or cytoplasmatic p16INK4a staining ≥20% was compared to HPV-negative tumor samples (median: 47.5%, interquartile range: 28.0%; p = 0.003).