RESUMO
Because primary breast tumors are diagnosed earlier in the clinic, procurement of sufficient amounts of tumor tissue for in-depth biological characterization is becoming increasingly difficult. We demonstrate here that relatively small numbers of tumor cells within samples of fine-needle aspirates (FNA) can be propagated in culture. Of 25 cases attempted, 12 were passageable, resulting in up to 10(7) viable cells. FNA-derived cultures were evaluated for anchorage-independence, c-erb-B2 overexpression, aneusomy, and pattern of allelic loss. In every case examined, the cultured cells closely resembled the original tumor tissue and displayed one or more tumor phenotypes. The incidence of erb-B2 overexpressing tumors was similar in passageable and nonpassageable cases (33% versus 31%, respectively). FNAs that are expanded from a wide range of clinical breast material could be useful for functional studies presently limited to rare established cell lines, such as aberrant signal transduction and gene regulation, and for testing potential anticancer vaccines and drugs.
Assuntos
Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Biópsia por Agulha , Neoplasias da Mama/metabolismo , Adesão Celular/fisiologia , Divisão Celular/fisiologia , Células Epiteliais/patologia , Feminino , Expressão Gênica , Humanos , Hibridização in Situ Fluorescente , Perda de Heterozigosidade , Receptor ErbB-2/biossíntese , Receptor ErbB-2/genética , Células Tumorais CultivadasRESUMO
Loss of heterozygosity (LOH) was detected in morphologically normal lobules adjacent to breast cancers. The most frequent aberration was at chromosome 3p22-25; of ten cases with this LOH in the carcinoma, six displayed the same LOH in adjacent normal lobules. This suggests that in a subset of sporadic breast cancers, a tumor suppresser gene at 3p22-25 may be important in initiation or early progression of tumorigenesis. Among sixteen breast cancers with LOH at 17p13.1 and five breast cancers with LOH at 11p15.5, one case each displayed the same LOH in adjacent normal lobules. Thus the molecular heterogeneity that characterizes invasive breast cancers may occur at the earliest detectable stages of progression.
Assuntos
Neoplasias da Mama/genética , Mama/patologia , Carcinoma Ductal de Mama/genética , Deleção de Genes , Alelos , Mama/química , Neoplasias da Mama/química , Neoplasias da Mama/patologia , Carcinoma Ductal de Mama/química , Carcinoma Ductal de Mama/patologia , Cromossomos Humanos Par 11 , Cromossomos Humanos Par 13 , Cromossomos Humanos Par 17 , Cromossomos Humanos Par 3 , DNA/genética , DNA de Neoplasias/genética , Feminino , Heterozigoto , Humanos , Reação em Cadeia da Polimerase , Receptor ErbB-2/análise , Proteína Supressora de Tumor p53/análiseRESUMO
Tissue clonality can be assessed in females by analyzing the methylation status of polymorphic DNA markers on X-linked genes because extensive de novo methylation of one allele at the preimplantation stage is associated with its permanent inactivation. We applied X chromosome inactivation toward understanding human breast morphogenesis by examining the nonmalignant breast epithelium from two reduction mammaplasties and a mastectomy. We found that entire lobules and large ducts of normal breast tissue have the same X chromosome inactivated, suggesting that they are derived from the same stem cell. The regions of inactivation of a particular X chromosome do not extend over an entire breast, so that ducts and lobules with opposite chromosomes inactivated are present within a single breast. Potential relevance of these observations for malignant transformation is discussed.