the fact that effective promoters of carcinogenesis in nonsquamous epithelia include drugs such as phenobarbital that are administered to humans in high doses for prolonged periods suggests that prenatal initiation followed by postnatal promotion may pose significant risks for humans , and should be considered in designing epidemiological searches for etiological factors that contribute to the incidence of epithelial tumours in man .
C0014609
epithelia
C1368683
epithelial tumours