ABSTRACT
Allele frequencies were calculated for three tetrameric short tandem repeats (STRs) located in intron 40 of the human von Willebrand factor (vWA, vWF1 and vWF2) in 352 white individuals sampled from an urban population from the northeastern region of the State of São Paulo, Brazil. The exact test did not indicate any significant deviation from HWE for any of the three investigated loci. The allele frequencies of vWA and vWF1 showed unimodal and bimodal distributions, respectively, and the frequencies of vWF2 in our sample exhibited bimodal or even trimodal patterns. These differing patterns could reflect the differential action of one selective factor or of the distribution of mutations in these STRs, although the STRs are very close to one another and belong to the same gene. The frequency of paternity exclusions observed for each of these three loci conform to the theorectical expectations. The lack of difficulties regarding the methodology of typing and the forensic value of statistical parameters confirm the usefulness of these systems to study Brazilian populations.
Subject(s)
Alleles , Gene Frequency/genetics , Genetics, Population , Tandem Repeat Sequences/genetics , von Willebrand Factor/genetics , Adult , Brazil , Child , Chromosome Mapping , Female , Humans , Introns/genetics , Male , Paternity , Polymerase Chain Reaction , Urban PopulationABSTRACT
Perianal basal cell carcinoma is a very rare tumor accounting for only 0.2% of the anorectal tumors. It must be distinguished from basaloid carcinoma of the anus, which resembles it histologically but shows a much more aggressive behavior, metastasizes early, and often proves fatal, thus requiring different therapy. Differential diagnosis of both entities by light microscopy may be difficult. Five cases of perianal basal cell carcinoma and five cases of basaloid carcinoma were studied by means of immunohistochemistry and flow cytometry. Some immunohistochemical markers, such as epithelial membrane antigen, carcinoembrionic antigen, and keratins, as well as the lectin Ulex europaeus agglutinin I stained basaloid carcinoma and were negative for basal cell carcinoma. In contrast, the monoclonal antibody Ber-EP4 seems to be a good marker for perianal basal cell carcinoma and useful in differentiating it from basaloid carcinoma of the anus. Basaloid carcinomas are associated with a significantly higher S-phase fraction than are perianal basal cell carcinomas (p < 0.01).
