Taken together, any one of either KDM5C mutation, loss of part or all of the X chromosome or loss of part or all of the Y chromosome causing loss of KDM5D might act to promote tumour formation, (i.e. the genes function as haploinsufficient tumour suppressors), but that rare bi-allelic inactivation of KDM5C in females or combined mutation of KDM5C and loss of the Y chromosome in males might also be selected for in some tumours, potentially providing additional attributes to those tumours. This evidence concerns the gene KDM5D and neoplasm.