NTIL A FEW years ago, it was doubtful U whether the mean zinc level of the blood of cancerous patients showed a decrease or an increase as compared with blood from healthy subjects. In a paper by Koch et al.4 in 1957, it was assumed that in the case of the lymphomatous diseases, the plasma zinc level is higher than it is normally. It is interesting to note that both Vikbladhll and Wolff12 found a reduction in level. Vikbladhll concluded from her experiments that the mean of the serum zinc content in 24 cases of malignant tumors was 105k4.4 y per 100 cc., with a standard deviation (S.D.) of 221.4-i.e., a statistically significant decrease as compared to the normal level of 1245~1.6 y per 100 cc, with a S.D. of 31t15.9. Wolffs values12 for the mean serum zinc level in cases of sarcoma and carcinoma were 104 y per 100 cc., as compared to the normal value of 130 y per 100 a.
The values found by Strock@ showed the same trend. On the other hand, Koch et al.' cited the work of Ortega Ortega8 who found that the blood zinc level was higher in cases of neoplastic diseases than it was normally. They added, however, that the specific types of neoplasms involved were not mentioned in Ortega Ortega's work. This is an essential point and one to which attention was drawn in our previous paper.* We found that in general the zinc content of whole blood of cancerous patients is subnormal (4.4 to 5.5 parts per million instead of the normal value of 6.4 parts per million), unless the tumor has developed in tissue relatively rich in zinc-such as bone, for instance, which contains about 200 parts per million (0.02%)-0r when the illness in-From the Spectrochemica1 Department, Philips Research Laboratories, N. v . Philips' Gloeilampenfabrieken, and the Cancer Subcentre, Eindhoven, Netherlands. Our thanks are due Dr. M. R. van A1 hen de Veer, Department of Health, N. V. Philips' &xilampenfabrieken, for his cordial cooperation, to Mrs. C. Meijer-Graot and Mr. H. F. van den Berg for their careful determinations of the zinc, iron, and water levels in a number of blood samples, and Dr. H. Hamaker and Mr. A. Witma for the application of the correlation c&cients.