DETECTION OF TP53 MUTATION, LOSS OF HETEROZYGOSITY AND DNA CONTENT INFINE-NEEDLE ASPIRATES OF BREAST-CARCINOMA

Recent preclinical and clinical data suggest that TP53 status and TP53 mutations may be important in determining tumour aggressiveness and t herapy response. In this study we investigate the feasibility of a str uctural and quantitative analysis of TP53 on fine-needle aspiration (F NA) material obtained from 31 consecutive female patients with breast carcinoma, enrolled in a primary chemotherapy protocol. Tumours were s creened for p53 protein overexpression and TP53 mutations (exons 5-8) using immunocytochemistry, polymerase chain reaction-single-strand con formation polymorphism (PCR-SSCP) and DNA sequencing analyses, and fin ally using fluorescence in situ hybridization (FISH) analysis. Positiv e nuclear staining was identified in six cases whereas mutations were detected in nine. Although the immunoreactive pattern fitted fully wit h the characterized TP53 mutation type, the considerable number of nul l p53 mutations (i.e. four) coupled with the lack of information regar ding the localization of TP53 mutations make immunocytochemistry an in adequate indicator of TP53 function deregulation. Combining molecular and FISH analyses, we detected three cases with TP53 deletion and one case with deletion and mutation. Finally, DNA static-image analysis pe rformed on 29 cases showed aneuploidy in 26 cases, which included all TP53-mutated cases. The present results show that FNA may assist clini cal decisions by allowing the evaluation of a variety of biological pa rameters relevant for prognosis and treatment planning.