Prevalence of c-myc expression in breast lesions associated with microcalcifications detected by routine mammography

• Published in: São Paulo medical journal Vol. 127; no. 2; pp. 66 - 70
• Main Authors: Mazzini, Renato Coimbra, Elias, Simone, Nazário, Afonso Celso Pinto, Kemp, Cláudio, Logullo, Angela Flávia
• Format: Journal Article
• Language: English; Portuguese
• Published: Brazil Associação Paulista de Medicina - APM 01.05.2009; Associação Paulista de Medicina
• Subjects: Adult; Biopsy, needle; Breast neoplasms; Breast Neoplasms - diagnostic imaging; Breast Neoplasms - genetics; Calcinosis - diagnostic imaging; Calcinosis - genetics; Carcinoma - diagnostic imaging; Carcinoma - genetics; Carcinoma in Situ - diagnostic imaging; Carcinoma in Situ - genetics; Carcinoma, Ductal - diagnostic imaging; Carcinoma, Ductal - genetics; Female; Gene expression; Gene Expression Regulation, Neoplastic - genetics; Humans; Hyperplasia - diagnostic imaging; Hyperplasia - genetics; Mammography; MEDICINE, GENERAL & INTERNAL; Original; Precancerous Conditions - diagnostic imaging; Precancerous Conditions - genetics; Prevalence; Proto-oncogene proteins c-myc; Proto-Oncogene Proteins c-myc - genetics; Proto-Oncogene Proteins c-myc - metabolism; Retrospective Studies; Biopsy, needle; Neoplasias mamárias; Biópsia por agulha; Mammography; Breast neoplasms; Gene expression; Expressão gênica; Proteínas proto-oncogênicas c-myc; Mamografia; Proto-oncogene proteins c-myc
• ISSN: 1516-3180; 1806-9460; 1806-9460; 1516-3180
• DOI: 10.1590/s1516-31802009000200003

Genetic abnormalities in cell proliferation-regulating genes have been described in premalignant lesions. The aims here were to evaluate c-myc protein expression in non-palpable breast lesions associated with microcalcifications, detected by screening mammography, and to compare these results with histopathological, clinical and epidemiological variables. Analytical cross-sectional study, with retrospective data collection, in a university hospital in São Paulo. Seventy-nine female patients who underwent routine mammography between 1998 and 2004 were studied. Lesions classified by the Breast Imaging Reporting and Data System (BI-RADS) as 4 or 5 underwent percutaneous biopsy using a large-core needle. Ninety-eight lesions were studied anatomopathologically. Paraffin blocks properly representing the lesions were selected for immunohistochemical analyses using the streptavidin-biotin-peroxidase technique with monoclonal mouse c-myc antibodies. Among the 98 lesions, 29 (29.6%) contained malignant neoplasia; 40 (40.8%) had a positive immunohistochemical reaction for c-myc. When the groups were divided between lesions without atypias versus atypical lesions plus malignant lesions, 31.03% of the 58 lesions without atypias were positive for c-myc and 55% of the 40 malignant and atypical lesions (P = 0.018). Comparing the atypical lesions with ductal carcinoma in situ versus the benign lesions without atypias, c-myc was present in 51.61% of the 31 atypical lesions and 31.03% of the benign lesions without atypias (P = 0.057). C-myc protein was more frequently expressed in atypical and malignant lesions than in benign lesions without atypias. C-myc expression correlated with the presence of atypias (P = 0.018).