“…More recent studies, however, with different methodologies have failed to confirm such a significant number of elevated isoenzyme levels (Jacoby and Bagshawe, 1972;Usategui-Gomez et al, 1973;Cadeau et al, 1974), so that the general and wide applicability once considered appropriate is now less certain. In addition early studies considered that the elevated levels were directly related to the tumour mass (Stolbach et al, 1969) but this is now open to doubt.…”