CDKN2A and neoplasm: The hazard ratio (HR) for PFS was even lower in cohort 1, where patients were included irrespective of cyclin D and p16 expression within the tumor, compared to cohort 2 (HR 0.299, 95 % CI 0.156 to 0.572 and HR 0.508, 95 % CI 0.303 to 0.853, respectively) [4].