Bishop H M, Blamey R W, Elston C W, Haybittle J L, Nicholson R I, Griffiths K
Lancet. 1979 Aug 11;2(8137):283-4. doi: 10.1016/s0140-6736(79)90295-2.
The oestrogen-receptor (E.R.) content of the primary tumour was measured in 133 postmenopausal women with operable breast cancer. 79 (59%) were positive for E.R. and 54 (41%) negative. Curves of life survival show that women with E.R.-positive tumours live longer than those with E.R.-negative tumours.