Histones and Cancer Test

Abstract

IN 1967, Tomasi and Kornguth¹ described the purification and partial characterization of a basic protein from pig brain which they later² suggested was a new tissue specific histone. This was a reasonable assumption considering the general properties of the molecule but it would now seem likely that this protein is in fact one of the basic proteins of myelin. It is now reasonably well established that it is the basic proteins extracted from myelin which are responsible for the experimentally induced allergic encephalomyelitis in animals³, and Bauer⁴ has recently suggested that there is statistical evidence for the homology of the main determinant of the human encephalitogenic protein (residues 112–122)⁵ and a part of the amino acid sequence of the histone fraction F2A1. The similarity between the amino acid composition of the myelin basic protein and histones has been noted² and the differences stressed⁵, but there can be no doubt that they are quite different proteins. Careful examination of the analysis given by Caspary and Field⁶ of their encephalitogenic protein of human origin and the purified histone fraction F2A1⁷, however, reveals a remarkable similarity. This being so, and because of the importance of the macrophage electrophoretic mobility (MEM)⁸ test, which may indicate the existence of malignant neoplasia particularly at an early stage of development, and because of the interest in the isolation of the tumour specific basic protein⁹, we thought it advisable to test the various histone fractions for their effect in this system. The five histones used were highly purified fractions prepared and characterized by methods which have all been described previously¹⁰. They were tested as described by Pritchard et al.¹¹ and the results are given in Table 1.