Clonality of the peripheral papilloma and cancerous cells of breast

Objective To study the clonality status of peripheral papilloma(peri-MP),ductal carcinoma in situ(DCIS),and normal tissue of the breast using an assay based on inactivation mosaicism of the length-polymorphic X-chromosomes at the androgen receptor(AR)locus and to explore a reliable way to distinguish the benign and malignant(or pre-malignant)cases judged morphologically.Methods Specimens of breast tissues were obtained from 26 cases of peri-PM,25 cases of peri-PM with atypical ductal hyperplasia(ADH),and 27 cases pf DCIS,16 cases of developed eanceration,and 20 normal women. DNA was extracted and amplified via nested-PCR with or without previous digestion by the methylation- sensitive restriction endonuclease Hha I.The products were resolved on denaturing polyacrylamide gels and visualized through silver staining.The clonality of these samples was analyzed by showing the lanes.Results Loss of polymorphism at the AR locus was found in all the cases with DCIS and in 10 cases(10/25, 40.0%)of peri-PM with ADH,indicating the monoclonality of the tumor.Twenty-four cases(92.3%)of the 26 cases with peri-PM and the 20 specimens of normal tissue were shown to be polyclonal.In the 16 cases of developed canceration identical X chromosome inactivation(monoclonal alterations)was observed in the cancer focus,parts of peri-PM with ADH,and the part of DCIS.Conclusion Normal breast tissue and peri-PM show polyclonahy and the peri-PM with ADH shows monoclonality.Clonality analysis may be a useful modality to screen high-risk cases from precancerous lesions or to distinguish between the benign hyperplasia and early carcinoma.