Human p14.5 perchloric acid-soluble protein (PSP) is a member of family (YER057c/YJGF family) of small proteins. The highly conserved throughout evolution proteins are characterized as multifunctional proteins comprised of ~ 80 homologues exhibiting varying degrees of sequence homology from 38% to 93%. The proteins involved in different cellular pathways of lower and higher eukaryotes. The biological role of these proteins is not yet well characterized. Human p14.5 protein is homologue of UK114 protein extracted from goat liver and characterized as tumor antigen. Antibodies against UK114 mediate in vitro complement-depended cytolysis of human cancer cells. This suggests that the expression of human p14.5 protein on the cells membrane might be an event related to neoplasmic transformation. The involvement of PSP into cellular growth and proliferation was discussed in several recent studies. All presented research findings demonstrate that human p14.5 gene acts as human cancer antigen and is involved into cellular proliferation events. Human p14.5 gene has been characterized by a differentiation-dependent mRNA and protein expression based on the observation of a low expression in a variety of liver and kidney tumor cells and a high expression in fully differentiated cells. At the beginning of the research study only kDNA sequence of human p14.5 gene was available. No data were available about human p14.5 gene full structure, coding protein p14.5 structure, biological functions... [to full text]