Evaluation of the polymorphisms in the exons 2 to 4 of the TP53 in cervical carcinoma patients from a Brazilian population

The majority of TP53 polymorphisms and cervical cancer association studies have only analyzed codon 72 polymorphism. Eight polymorphisms were reported in the region encompassing exon 2 to 4 of TP53 that codify the aminoterminal p53 region containing domains involved in the transcription transactivation and apoptosis induction. We investigated if the polymorphisms present in this region were associated with cervical cancer risk. A total of 140 samples (83 from Brazilian patients with cervical carcinoma and 57 from Brazilian healthy women) were analyzed by PCR and DNA sequencing. Only three from the eight TP53 polymorphisms described in the analyzed region were polymorphic within our samples: the 11827 base from intron 2, the 16bp duplication in the intron3 and the codon 72 (Arg>Pro) from exon 4. No statistically significant association was observed between polymorphisms from intron 2 and the 16bp duplication from intron 3 with cervical cancer. No statistically significant difference in the frequency of homozygotes for Arg in relation to other genotypes was found when comparing patient and healthy groups (OR=0.70; 95% CI= 0.31-1.56; p= 0.222). However, Arg/Pro heterozygotes were more frequent within HPV positive cancer patients than in healthy women (p=0.023; OR (Arg/Pro:Pro/Pro)= 5.82; 95% CI: 1.22-30.78; p=0.024).

A polymorphism in exon b2 of the major breakpoint cluster region (M-bcr) identified in chronic myeloid leukaemia patients

The BCR/ABL junctional region and the b3 exon from chronic myeloid leukaemia (CML) patients were sequenced. In all 21 samples analysed the junctional region, as well as the b3 exon of 8 b3a2 mRNA molecules, presented no differences to the already described sequences. However, we identified a polymorphic base in the b2 exon in two out of seven b3a2 samples, four out of 10 b2a2 samples and all four b3a2/b2a2 samples analysed. In the eighth position before the junctional region of BCR/ABL cDNA, a cytosine replaces thymine in these cases. The polymorphism described here could be a useful marker for the differentiation of normal and rearranged BCR alleles in heterozygotes.