An intronic variant in the TP53 gene in a Brazilian woman with breast cancer.

We screened the TP53 gene for mutational status in 40 breast tumor cases by polymerase chain reaction, single-strand conformational polymorphism, and gene sequencing. Many mutations of this gene have been described in specific databases. In our study, a new T-->C point mutation was identified in intron 6 at position 13989 in a grade III medullary ductal carcinoma. Other variations in intron 6 have been described in patients with Li-Fraumeni syndrome. One of these variations was reported to inhibit apoptosis and prolong cell survival, thereby increasing breast cancer risk. Nevertheless, more studies are necessary to establish whether this mutation has a role in breast cancer risk.