Human epithelial cells contain, intermediate-sized filaments formed by polypeptides related
to epidermal α-keratin (“cytokeratins”) which are expressed in different combinations in
different epithelia. Using cytoskeletal proteins from human biopsies and autopsies we have
examined, by two-dimensional gel electrophoresis and immunoblotting experiments, the
cytokeratin polypeptide patterns of diverse primary and metastatic carcinomas and have
compared them with those of corresponding normal epithelial tissues and cultured cells …