CARCINOSARCOMA OF THE BREAST - MOLECULAR-BIOLOGICAL STUDY FOR ANALYSIS OF HISTOGENESIS

The histogenesis of carcinosarcoma of the breast is controversial, In the current case, the demarcation between the carcinomatous and sarcom atous components was distinct in all microscopic fields. Immunohistoch emical analysis was negative for epithelial membrane antigen (EMA) and keratin in the sarcomatous component and was negative for desmin in t he carcinomatous component, suggesting that this tumor could be derive d from the two different stem cells. To determine the histogenesis of this tumor, both carcinomatous and sarcomatous lesions were microdisse cted from formalin-fixed tissues and DNAs were prepared by proteinase K digestion. PCR amplification of the human androgen receptor (HUMARA) short tandem repeat (STR), after Hpa II digestion of the genomic DNA, indicated that the patterns of X-chromosome inactivation were identic al in both components. Moreover, both components contained the identic al TGT --> TTT transversion in codon 275 of the p53 gene. These observ ations strongly support the hypothesis that this tumor is derived from a single totipotent stem cell. Copyright (C) 1998 by W.B. Saunders Co mpany.