Alkaline Phosphatase of Cancerous Larynx Tissue in Comparison with the Placental Enzyme: Biochemical and Histochemical Studies

Tissue specimens of squamous cell carcinoma of the larynx from twenty patients were processed for histological and histopathological characterization. A histochemical study of alkaline phosphatase (ALP) was carried out using the simultaneous azo coupling method, and biochemical studies were performed using disodium phenylphosphate as substrate. Full-term, normal placentae were used for comparison. The specific activity of ALP from cancerous laryngeal tissue was 8.9 mKAU/mg protein compared with 154.7 mKAU/mg protein in the placenta. The ALP was localized histochemically in tumor cells (tumor-specific), blood vessels (vascular) and fibrous tissue (interstitial). The tumor-specific phosphatase was sensitive to inhibition by L-phenylalanine, L-leucine and to a lesser degree by L-tryptophan and levamisole. Placental ALP, on the other hand, was completely inhibited by levamisole, more resistant to leucine and more sensitive to phenylalanine and tryptophan. Biochemical estimation of ALP in cancerous laryngeal t...