title: Primary mammary small-cell carcinoma: a molecular analysis of 2 cases.
abstract: Primary small-cell carcinoma of the breast is an exceedingly rare variant of breast carcinoma whose genetic profile has not been previously investigated. We report the molecular features of 2 cases of small-cell carcinoma of the breast: 1 with an adjacent intraductal carcinoma, and 1 with prior pleomorphic lobular carcinoma in situ. Laser capture microdissection followed by loss of heterozygosity (LOH) analysis revealed identical molecular alterations at multiple chromosomal regions, including BRCA-1, BRCA-2, p53, and retinoblastoma gene loci, in 1 case of small-cell carcinoma and its adjacent intraductal component. Additionally, LOH in 1 or both small-cell carcinomas was detected at 3p, 4q31.2-qter, 8p21-24, 11q13 (MEN-1 locus), 11q23.3, 11q24.1-25, 16q24.1 (H-cadherin locus), and 17q25. The results of our molecular analysis suggest that genetic changes in mammary small-cell carcinoma resembled those seen in both invasive ductal carcinomas and pulmonary small-cell carcinoma. Second, mammary small-cell carcinoma is clonally related to ductal carcinoma in situ and might represent an example of divergent differentiation occurring in a multipotential neoplastic stem cell.
authors.affiliation: Division of Anatomic Pathology and Hamon Center for Therapeutic Oncology Research, Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
authors.forename: M P
authors.initials: MP
authors.lastname: Hoang
authors.forename: A
authors.initials: A
authors.lastname: Maitra
authors.forename: A F
authors.initials: AF
authors.lastname: Gazdar
authors.forename: J
authors.initials: J
authors.lastname: Albores-Saavedra
mesh_terms: D000328:Adult; D000951:Antigens, Neoplasm / Q000032:analysis; D014408:Biomarkers, Tumor / Q000032:analysis; D001943:Breast Neoplasms / Q000737:chemistry / Q000235:genetics* / Q000473:pathology / Q000601:surgery; D018288:Carcinoma, Small Cell / Q000737:chemistry / Q000235:genetics* / Q000473:pathology / Q000601:surgery; D004252:DNA Mutational Analysis; D004273:DNA, Neoplasm / Q000032:analysis; D004210:Dissection; D005260:Female; D005819:Genetic Markers / Q000235:genetics; D006801:Humans; D007124:Immunoenzyme Techniques; D019656:Loss of Heterozygosity; D008846:Micromanipulation; D008875:Middle Aged; D016133:Polymerase Chain Reaction
chemical_list: D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D004273:DNA, Neoplasm; D005819:Genetic Markers