Lactate dehydrogenase activity in laryngeal carcinoma and surrounding mucosa.

The total lactate dehydrogenase (LDH) activity and LDH isoenzyme pattern were measured in tissue taken from laryngeal cancers and from the laryngeal mucosa both close to and distant from the tumour margin. An increase in the total LDH activity and a cathodic shift in the isoenzyme pattern were found in tumour tissue compared to the close and distant mucosa. However, significant LDH alterations in the mucosa close to the tumour were shown in comparison to the distant mucosa and to the laryngeal mucosa of controls. Histochemical studies showed the LDH activity to be located in the basal and parabasal layers of the epithelium and in the cancer foci.