TP53 and neoplasm: We chose to search for connections between p53 and the X chromosome because: (1) numerous tumour-suppressor genes are encoded on the X chromosome26, but are under-studied for connection to p53 and sex disparity; (2) X-chromosome genes are not yet incorporated into established p53 networks (eg. KEGG16); (3) X-chromosome analysis is frequently avoided in sporadic diseases because X-inactivation (Xi) silencing in females complicates data interpretation (reviewed in refs. 27,28) and (4) males are at greater disease risk than females from X-chromosome mutations (reviewed in ref. 29).