Abstract
The indirect immunofluorescence technique demonstrated that human alpha fetoprotein (AFP) was present in a focal pattern in the cytoplasm of malignant liver cells of patients whose sera contained AFP. A few fibroblastlike cells in tissue culture of liver biopsies from patients with hepato-cellular carcinoma and AFP in their sera also had the protein. The intracellular localisation of human AFP was confirmed by centrifugation of washed, homogenised and ultra-sonically disrupted neonatal liver cells. Examination of livers of fetuses and neonates showed that AFP was present predominantly in the periportal parenchymal cells.