Types of cyclic AMP binding proteins in human breast cancers.

Total level and type of cyclic AMP binding proteins have been measured in 117 breast cancers. Six major molecular species of binding proteins were detected. The pattern and relative proportion of binding proteins varied between individual tumours. However, there were highly significant correlations between the expression of different binding proteins, including positive relationships between 52 and 67 kD proteins, 43 kD and both 39 and 37 kD proteins and inverse correlations between 48 and 52 kD, 37 and 67 kD proteins. The expression of three binding proteins (48, 43 and 39 kD) was also positively related to total binding whereas that of the remaining three bindings proteins (67, 52 and 37 kD) was negatively correlated with total levels. It may be that differential expression of certain types of binding protein are the underlying rationale for our previously published finding that tumours with high levels of high binding protein are associated with poor prognosis.