[Comparative electron microscopic study of cancer cell differentiation in the primary tumor and the metastases].

Comparative ultrastructural analysis of primary carcinomas of the lung, mammary gland, colon, stomach and some other sites and their metastases into the lymph nodes and inner organs is presented. It is established that the main ultrastructural specific features of differentiation typical for the cells of primary tumours are, as a rule, retained in their metastases to various organs and tissues. Carcinoma cells in the metastases repeat most frequently (81% of cases) the types of differentiation of a primary tumour. However, the reduction of a number of differentiated cell types (5%) or appearance of a new ultrastructural cell type (14%) may be found in the secondary tumour deposits. Besides, the retention (74%), decrease (10%) or increase (16%) of the degree of differentiation may be observed in metastases as compared to the primary tumour. The data obtained may be the ground for a proper identification of malignant tumours on the basis of the electron microscopic study of their metastasis.