The Pathology of EMT in Mouse Mammary Tumorigenesis

Epithelial-mesenchymal-transition (EMT) tumorigenesis in the mouse was first described over 100 years ago using various terms such as carcinosarcoma and without any comprehension of the underlying mechanisms. Such tumors have been considered artifacts of transplantation and of tissue culture. Recently, EMT tumors have been recognized in mammary glands of genetically engineered mice. This review provides a historical perspective leading to the current status in the context of some of the key molecular biology. The biology of mouse mammary EMT tumorigenesis is discussed with comparisons to human breast cancer

A HISTOCHEMICAL AND ELECTRON MICROSCOPIC STUDY OF SKELETAL MUSCLE IN A CASE OF POMPE'S DISEASE (GLYCOGENOSIS II)

1. A case of Pompe's disease (glycogenosis II) without biochemically or histochemically demonstrable alpha-glucosidase activity is described. 2. Histochemical studies of skeletal muscle suggested that the glycogen is frequently stored as an acid mucopolysaccharide. 3. Electron microscopic studies revealed that the major glycogen deposits in most tissue were within membrane-limited sacs. Striated muscle was an exception because major deposits were frequently extrasaccular. 4. The findings in this case are discussed in relation to current concepts of Pompe's disease. In view of the extrasaccular glycogen deposits in skeletal muscle, it is suggested that an extralysosomal factor plays a significant role in the pathogenesis of Pompe's disease.</jats:p

Lunatic Fringe Deficiency Cooperates with the Met/Caveolin Gene Amplicon to Induce Basal-like Breast Cancer

SummaryBasal-like breast cancers (BLBC) express a luminal progenitor gene signature. Notch receptor signaling promotes luminal cell fate specification in the mammary gland, while suppressing stem cell self-renewal. Here we show that deletion of Lfng, a sugar transferase that prevents Notch activation by Jagged ligands, enhances stem/progenitor cell proliferation. Mammary-specific deletion of Lfng induces basal-like and claudin-low tumors with accumulation of Notch intracellular domain fragments, increased expression of proliferation-associated Notch targets, amplification of the Met/Caveolin locus, and elevated Met and Igf-1R signaling. Human BL breast tumors, commonly associated with JAGGED expression, elevated MET signaling, and CAVEOLIN accumulation, express low levels of LFNG. Thus, reduced LFNG expression facilitates JAG/NOTCH luminal progenitor signaling and cooperates with MET/CAVEOLIN basal-type signaling to promote BLBC