CDKN2A and lung cancer: However, our previous studies in primary NSCLC, a large number of human lung cancer cell lines, and primary tumor samples identified a region of homozygous deletion (HD) at the microsatellite marker D9S126 which is distinct from the p16/CDKN2A locus and lies approximately 3.7 Mb proximal to p16/CDKN2A, [10], [14].