Abstract: A structurally modified protein is provided that will bind to a tumor-associated structure wherein the amino group in at least one basic amino acid in the binding protein is structurally modified to convert the amino group, --NH.sub.2, to the grouping --NH--CO--X--NHR in which R is H or an amino protecting group and the grouping --CO--X--NHR is the residue of a peptide of the formula NHR--X--COOH capable of acting as a substrate for a phosphokinase.

Abstract: Nucleoside thiotriphosphates carrying .sup.32 P in the gamma-thiophosphate group, prepared by reaction between a nucleoside diphosphate and .sup.32 p labelled thiophosphate salt, are used as thiophosphorylating agents for antibodies that bind to tumour-associated antigens. The labelled thiotriphosphates can be used to introduce a therapeutically useful .sup.32 P atom into an antibody that has been modified by the incorporation into its structute of a peptide region capable of acting as a substrate for a phosphokinase. The resulting labelled antibody can then be used for injection in anti-tumour therapy and has clinical advantages over the corresponding phosphoylated analogue.

Abstract: A pharmaceutical composition useful for aiding regression and palliation of cancer in mammals comprises a therapeutically effective amount of a compound of formula ##EQU1## wherein R.sub.1 and R.sub.2 are each separately selected from hydrogen and methyl or together represent an ethylene bridging group, with the proviso that when both of the groups R.sub.1 and R.sub.2 are methyl they are disposed in the meso configuration, or a non-toxic salt thereof with a physiologically acceptable inorganic or organic acid, in combination with a physiologically acceptable diluent or carrier.