Vimentin-positive adenocarcinomas of the stomach: co-expression of vimentin and cytokeratin

Recently, the expression of vimentin has been reported in some carcinomas. This study was designed to clarify the significance of vimentin expression in solid type poorly differentiated adenocarcinomas of the stomach. Immunohistochemically, 239 poorly differentiated adenocarcinomas with solid components of the stomach were stained for vimentin. Vimentin-positive cases were also stained by CAM 5.2 using serial mirror sections. We found 15 (6.3%) vimentin-positive cases. Twelve of them demonstrated varying amounts of rhabdoid-like cells. Eight cases diffusely co-expressed vimentin and cytokeratin simultaneously. In addition, four co-expressing cases showed positive staining with Keratin-903 which recognizes the high molecular-weight cytokeratin. Most of the co-expressing cases showed a diffuse proliferation of polygonal tumour cells with focal cell-to-cell contact. The prognosis of the co-expressing cases was poor in comparison with that of the 89 vimentin-negative tumours ( P < 0.05).