Immunohistochemical substantiation of the possibility of use electrochemical method whith using nanotechnological biosensors for assessing alkaline phosphatase activity in tissue colorectal carcinoma

Abstract

Introduction. Alkaline phosphatase (ALP) is an enzyme from the class of hydrolases, widely present in human tissues and organs. Intestinal ALP is one of the enzyme isoforms that is expressed in the mucous membrane throughout the intestine and is a marker of intestinal epithelial differentiation. It is known that the products of the chemical reaction between intestinal alkaline phosphate and a specific substrate, 1-naphthyl phosphate, have electrochemical activity. This makes it possible to evaluate the activity of the enzyme in biological tissues using the electrochemical method using nanotechnological biosensors. The aim of the study. To evaluate the diagnostic significance of the electrochemical method for assessing alkaline phosphatase activity by comparing it with the results of histological and immunohistochemical studies in colorectal carcinoma. Material and methods. A parallel electrochemical and morphological (histological and immunohistochemical with antibodies to intestinal alkaline phosphatase) study of material from colorectal carcinoma and the colon mucosa outside the tumor of 78 patients was carried out. Results. In 70 patients, the current obtained from electrochemical study of tumor biopsies was significantly lower (49.2 nA (95% CI 41.3–88.9) than in biopsies of the intestinal mucosa outside the tumor (119.7 nA (95% CI 96.8–167.1), p<0.05). Histologically, the tumor tissue was represented by adenocarcinoma of varying degrees of differentiation. An immunohistochemical study revealed that the expression of intestinal ALP was absent in carcinoma cells, while in the epithelium of the colon mucosa outside the neoplasm, pronounced diffuse membrane expression of the enzyme was noted. In 8 patients, there was no association between the results of electrochemical and morphological studies due to the presence of non-tumor tissues in the material. An immunohistochemical study revealed that intestinal alkaline phosphatase can be expressed in immune cells and neurons of the submucosal nerve plexuses. Conclusion. A comparison of the results of electrochemical, histological and immunohistochemical studies indicates that the electrochemical method has a high diagnostic value and can be used in screening for colorectal carcinoma.