P53 and the Carcinoma of the Breast: A Review
P53 and the Carcinoma of the Breast
Background: TP53 is a gene and p53 is its product protein. Since its discovery many studies have looked into its function and its role in cancer. It is not only involved in the induction of apoptosis but is also, a key player, in cell cycle regulation, development, differentiation, gene amplification, DNA recombination, chromosomal segregation and cellular senescence and so, it is called “the guardian of genome”. The human TP53 gene spans 20kb on chromosome band 17p13.1. The biological functions of p53 are apoptosis, senescence and cell migration. The evolution of a normal cell towards a cancerous one is a complex process. Tumorogenesis is considered to endow, the evolving tumor with, self-sufficiency of growth signals, insensitivity to antigrowth signals, evasion from programmed cell death, unlimited replicative potentials and finally the ability to invade and metastasize. TP53 may be considered as the “ultimate tumor suppressor gene”. Its oncogenic activity is attributed to loss of function, dominant negative (DN) oncogenic properties and activities of mutant p53. In breast cancer its oncogenic function is due to p53 mutation, changes in- upstream regulatory pathways, in p53 transcriptional target genes, in p53 co-activators, and/or involvement of other family members of p53 family like p63 and p73. The p53 mutation is present in only in about 20% of breast cancers, but when present, they entail the worst prognosis. This interesting paper is a review and discussion about role of p53 in carcinoma breast.