No relationship between lactate dehydrogenase and estrogen receptor levels in clinical human breast cancer.

The level of lactate dehydrogenase has been reported to increase in a human breast cancer cell line as a result of estrogen action [4]. This finding suggests that lactate dehydrogenase may be useful in clinical human breast cancer as a marker for intactness of the estrogen receptor pathway and for probability of response to hormonal therapy. In 97 hunan breast cancer specimens submitted for estrogen receptor analysis, the level of lactate dehydrogenase varied from 0.19 to 3.3 I.U. per mg of extractable protein and bore no relation with either the presence of estrogen receptor or its level. It thus appears that lactate dehydrogenase is not a useful marker for endocrine responsiveness in clinical breast tumors.