<unk>  is a protein related to the p53 tumor protein. Because of its structural resemblance to p53, it has also been considered a tumor suppressor. It is involved in cell cycle regulation, and induction of apoptosis. Like p53,<unk>  is characterized by the presence of different isoforms of the protein. This is explained by splice variants, and an alternative promoter in the DNA sequence.<unk> , also known as tumor protein 73 (TP73), protein was the first identified homologue of the tumor suppressor gene, p53. Like p53,<unk>  has several variants. It is expressed as distinct forms differing at either at the C- or the N-terminus. Currently, six different C-terminus splicing variants have been found in normal cells. The<unk>  gene encodes a protein with a significant sequence homology and a functional similarity with the tumor suppressor p53. The over-expression of<unk>  in cultured cells promotes a growth arrest and/or apoptosis similarly to p53. The<unk>  gene has been mapped to a chromosome region (1p36. 2-3) a locus commonly deleted in various tumor entities and human cancers. Similar to p53 the protein product of<unk>  induces cell cycle arrest or apoptosis, hence its classification as a tumor suppressor. However unlike its counterpart,<unk>  is infrequently mutated in cancers. Perhaps, even more shocking is the fact that<unk>  – deficient mice do not show a tumorigenic phenotype. A deficiency of p53 almost certainly leads to unchecked cell proliferation and is noted in 60% of cancers. Analyses of many tumors typically found in humans including breast and ovarian cancer show a high expression of<unk>  when compared to normal tissues in corresponding areas. Adenoviruses that cause cellular transformations have also been found to result in increased<unk>  expression. Furthermore, recent finding are suggesting that over-expression of transcription factors involved in cell cycle regulation and synthesis of DNA in mammalian cells (e.g.: E2F-1) induces the expression of<unk> . Many researchers believe that these results imply that<unk>  may not be a tumor suppressor but rather an oncoprotein. Some suggest that the TP73 locus encodes both a tumor suppressor (TAp73) and a putative oncogene (ΔNp73). This is a strong theory and causes much confusion, as it is unknown which of the two<unk>  variants is over-expressed and ultimately plays a role in tumorigenesis. Genes of the p53 family are known to be complex. The viral oncoproteins (e.g. Adenovirus E1B) that efficiently inhibit p53 function are unable to inactivate<unk> , and those that seem to inhibit<unk>  have no effect on p53. Debate persists about the exact function of<unk> . Recently it has been reported that<unk>  is enriched in the nervous system and that the<unk> -deficient mice, which do not exhibit an increased susceptibility to spontaneous tumorigenesis, have neurological and immunological defects. These results have been expanded and it has also been shown that<unk>  is present in early stages of neurological development and neuronal apoptosis by blocking the proapoptotic function of p53. This strongly implicates<unk>  as playing a large role in cellular differentiation.
P73
BRAF 
INK4
AP-7 
ABL 
BIM-1
TFM-4AS-1
ERCC2