Background: The diagnosis of breast cancer based on nipple discharge, often the only clinical manifestation of early breast cancer, is currently unsatisfactory. Because M subunits of lactate dehydrogenase (LDH) have been noted to increase in cancer tissue, the author assessed the value of using LDH isozyme patterns in nipple discharge for the diagnosis of breast cancer.
Methods: LDH isozyme levels in (1) nipple discharge of patients diagnosed as having breast cancer, intraductal papilloma, mastopathy, drug-induced nipple discharge, mastitis, or benign nipple discharge; (2) control samples of normal nipple discharge (milk) 6 days, 1-5 months, and 6 months to 2 years postpartum; (3) the serum of patients presenting with nipple discharge; and (4) normal and cancerous breast tissue extracts were measured using a Ciba-Corning LDH isozyme system (Ciba Corning Diagnostic Corp., Tokyo, Japan).
Results: LDH isozyme levels in the nipple discharge of patients with benign breast diseases displayed various patterns. Levels in the nipple discharge of patients with breast cancer, including noninvasive carcinoma, tended to increase in ascending order from LDH1 to LDH5. This pattern was similar to that in breast cancer tissue and was unrelated to the pattern in serum.
Conclusion: LDH isozyme assay of nipple discharge may be a useful technique for providing a supporting diagnosis of breast cancer.