Detection of R337H, a germline mutation predisposing to multiple cancers, in asymptomatic women participating in a breast cancer screening programme in southern Brazil

21029 Background: A specific germline mutation at codon 337 in TP53 (R337H) has been detected in a number of unrelated subjects with familial cancer risk in South Brazil, suggesting that this mutation may be relatively common in this population. Methods: To assess the TP53 R337H prevalence in a group of asymptomatic individuals unselected for family history of cancer, we studied 750 women aged 40–69 ys participating in a mammographic screening programme in Porto Alegre, Brazil`s southernmost capital. DNA was extracted from peripheral blood using standard procedures and PCR-amplified to generate a 238-base product encompassing TP53 exon 10, which was analyzed by RFLP using the restriction enzyme HhaI. The mutant, uncleaved allele was identified in agarose gels and positive RFLP findings were further confirmed by an independent PCR amplification and bi-directional, automated sequencing. Results and Discussion: The R337H mutant was detected in two of the 750 participants (0.15%), suggesting a much higher pre...