Twenty-five primary gastrointestinal
carcinomas have been studied using immunofluorescence microscopy with affinity-purified
antibodies to
prekeratin and to
vimentin. The tissues were alcohol fixed and
paraffin embedded before use. In all cases (i.e., one case of esophagal
carcinoma, seven stomach
carcinomas, and 17 large bowel
carcinomas) the
tumor cells are stained by
antibodies to
prekeratin. In cases in which only very few
tumor cells are present, such as signet ring
carcinoma, immunofluorescence with
prekeratin antibody provides an easy way to visualize single
tumor cells. When the same specimens were tested with
antibodies to
vimentin, the
tumor cells were unstained, and only the fibroblasts and vessels of the stroma were decorated. Four of the
tumors were also negative when tested with
antibodies specific for either
desmin, or
glial fibrillary acidic protein or neurofilaments. Three
metastases to the abdominal region from
tumors originating in the ovary, stomach, and large bowel were like the primary
tumors in that the
tumor cells were positive when stained with
antibodies to
prekeratin and negative when tested with the
antibodies to
vimentin.