RESUMO
PURPOSE OF INVESTIGATION: The fragile histidine triad (FHIT) gene is a tumor suppressor frequently inactivated in various types of tumors. The authors evaluated the occurrence of loss of heterozygosity (LOH) in the FHIT locus and FHIT protein changes in breast tissue. MATERIALS AND METHODS: Blood and breast tissue samples were obtained from 35 women with mammary disorders. The occurrence of LOH in FHIT locus was assayed by polymerase chain reaction (PCR), and the results obtained from blood and breast tissues from each patient were compared. FHIT protein expression was evaluated by immunohistochemistry. RESULTS: LOH in the FHIT gene occurred in 48.6% (17/35) of patients with mammary disorder. Among patients with malignant breast disorders, 59.1% (13/22) presented LOH in the FHIT gene in comparison with patients with benign breast lumps, in which the LOH was observed in 30.8% (4/13) of women, suggesting that changes in this gene occur prior to the process of mammary carcinogenesis. The changes in the locus of the FHIT gene occur with greater frequency in the coded region of the gene, principally near exons 5 and 8, where the FRA3B site and the histidine triad respectively are found. Changes in FHIT did not modify protein expression. The association between menopause and LOH in the FHIT gene was evident. CONCLUSIONS: LOH in the FHIT gene may be related to menopause in women with breast disorders.
