TP53 and breast neoplasm: This is most probably true and such hypothesis is consistent with experimental evidence showing abnormal expression of p53 isoforms in breast tumors [57]: p53β, which lacks the carboxy-terminal oligomerization domain due to alternative mRNA splicing; Δ133p53, which lacks the amino-terminal transactivation and proline-rich domains due to the transcription from an alternative promoter in intron 4; Δ40p53, also named p47 or ΔNp53, as an amino-terminally truncated p53 isoform deleted from the first 40 amino acids.