We hypothesized that, if PLAC1 antigen is involved in the aberrant proliferation of tumor cells so as to hypothesize a “trophoblastic theory of cancer”, an aberrant secretion of PLAC1 might be similarly responsible for a behavior analogous to that of cancer in the trophoblast of preeclamptic placentas, and, as a consequence, an “oncogenic theory of preeclampsia” should be considered. This evidence concerns the gene PLAC1 and neoplasm.