Intracellular filaments in human cancer cells: a histological study.

The distribution of intracellular filamentous systems in human breast and colonic cancers has been demonstrated by means of the tannic acid-phosphomolybdic acid-milling dye staining technique. Plasma membrane-associated staining is prominent in breast carcinomas and is strongest in anaplastic tumours. Strong staining is also noted in the cells at the margins of the tumours where the malignant cells are invading the surrounding tissues. In colonic carcinomas, filaments are mainly restricted to the terminal web region of the cells but dedifferentiation is accompanied by the development of circumferential staining of the cell membrane. The results are discussed in relation to immunohistochemical and electron microscopic studies of contractile proteins in non-muscle cells.