CDKN1A and childhood malignant neoplasm: In a previous work, we have reported the downregulation of Cell cycle checkpoint control protein RAD9A (RAD9A and Cyclin Dependent Kinase Inhibitor 1A (﻿CDKN1A) in non-irradiated (Victor et al. 2013a) and irradiated [1 Gy, (Weis et al. 2011)] fibroblasts of former childhood cancer patients with at least one second primary neoplasm (N2+), compared to former childhood cancer patients with a first primary neoplasm only (N1).