The level of serum alpha-fetoprotein (AFP) was estimated by radioimmunoassay in 153 normal healthy Malysians of different ethnic groups. The mean level was 7.5 In1/ml (SD 2.28InU/ml). Among 330 patients with malignant tumors, 11 had increased levels of AFP. The only patient who had hepatoma had a very high level of serum AFP. High levels were also found in three of four patients with dysgerminoma of the ovary, in the only two patients with carcinoma of the testis, and in one patient with secondary carcinoma of the humerus of unknown origin. Lower, but significantly increased levels were observed in one patient (of 48) with breast carcinoma, one patient (of 8) with basal cell carcinoma of the nose, one patient (0f 27) with carcinoma of the lung, and one patient (of 59) with nasopharynegeal carcinoma.
Alpha-Fetoprotein (AFP) levels of 1,335 males (15 years and older) of seven ethnic groups (Chinese, Indians, and Malays from Singapore, Caucasians from Lyon, and Blacks from Nairobi, forest, and the savanna region of the Ivory Coast) were determined by radioimmunoassay. A few elevated levels (up to 30 nanounits/ml) were detected in some normal individuals, especially in the older age-groups. In addition, there was a systematic age-dependency of AFP levels particularly evident in the groups from Singapore-Lyon, in which there was a 50% AFP increase between the ages of 20 and 40. Comparison between Africans on the one hand and people from Singapore-Lyon on the other hand revealed highly significant differences (p less than 0.001), especially in the younger groups, whereas Chinese, Malays, and Indians from Singapore had very similar AFP pattern; this suggests an important role for environmental factors in the regulation of AFP levels. The age dependency of the presumed effect of environmental factors is in keeping with experimental data showing that young animals respond more vigorously to AFP-stimulating factors. Although the incidence of hepatocellular carcinoma (HCC) differs in the three Singapore groups (the highest in Chinese and the lowest in Indians), no relationship was observed in this study between mean AFP level and HCC incidence in Singapore.