Interrelationship of prealbumin and α‐1 acid glycoprotein in cancer patient sera

The ratio between two serum components (α‐1 acid glycoprotein/prealbumin) may be useful as a cancer serum index (CSI). By use of scanning densitometry quantitation of serum components after separation by gradient polyacrylamide gel electrophoresis (PAGE) precise measurements are obtained for protein content of thyroxin‐binding prealbumin levels, which decrease in cancer patient sera, and of α‐1 acid glycoprotein levels, which increase significantly in cancer patient sera. The conventional Mancini method was used for corroboration of these observations. The Mancini method, although reliable, is not as quantitative nor as sensitive in the evaluation of differences, particularly for a discrimination of values obtained from healthy adults, smokers, and benign diseased patient sera, all of which were used as controls. CSI, by densitometry quantitation, was determined for controls as well as for patients with early and late lung cancer, colon cancer, melanoma and breast cancer, with concomitant measurements of these same sera using the Mancini method. Independent observations using the Mancini method were made by the Leeds' group for patient sera from early and late colon cancer, and early and late prostate cancer groups. Both the G.W.U. and the Leeds' groups tested sera from patients with each stage of bladder cancer. The Leeds' Mancini method gave CSI for T₂ of 3.6, for T_2‐3 of 4.9, for T₄ of 8.9 and for tumor‐free patients 3.5. Using the PAGE densitometry method, G.W.U. measurements of CSI for bladder cancer were as follows: T₁ − 1.05, T₂ − 2.40, T₃ − 5.57, T₄ − 11.0 and tumor‐free −1.73, respectively. Thus, independent measurements by two different laboratories (Leeds and G.W.U.) confirm the observation that CSI may provide a practical addition, similar to albumin measurements and other valuable indicators, for the clinician's armamentariam. Cancer 40:2993‐2998, 1977.