Abstract
Alphaβfetoprotein (AFP) and carcinoembryonic antigen (CEA) were determined simultaneously in serial samples from patients with teratocarcinomas, testicular tumors of soβcalled embryonic origin. These tumorβassociated fetal substances were seen together in four cases, AFP alone was seen in five, CEA in three and neither antigen in two. The embryonic cancer component was present in all primary tumors in which either fetal antigen was detected. AFP was clearly related to progression or regression of tumor while CEA occurred transiently. Four primary teratocarcinomas and four seminomas were established in shortβterm tissue culture. Only one of these particular patients had raised serum AFP levels. When, however, the original tumorβcell suspensions were assayed by radioimmunoassay or indirect immunofluorescence, AFP was detected in three out of the four teratocarcinomas. CEA was seen in a low percentage of cells from two primary teratocarcinomas. No seminoma cells contained either of the antigens. This means that perhaps most teratocarcinomas do indeed produce AFP and/or CEA, although serum assays may be negative. No relationship was found between the occurrence of the two fetal substances.