Oestrogen receptor content and cancer cell/stroma ratio in mammary carcinoma

In a study of 86 human breast cancers the volume fraction of the neoplastic epithelium was estimated semiquantitatively and a significant association was found between the oestrogen receptor (ER) content and volume fraction of cancer cells of tumours (p less than 0.00001). Tumours with very low cellularity could thus be falsely ER negative. When quantitative ER concentration is used to predict the response of tumours to hormonal therapy the cellularity of tumours should be taken in consideration. The cellularity was not related to ER positivity. Although a correlation was seen between the contents of oestrogen and progesterone (PR) receptors, no correlation between PR content and volume fraction of the neoplastic epithelium was observed.