[The role of stem and pluripotent cells in differentiation and the neoplastic transformation of pancreatic cells].

Certain differentiation-specific antigenic determinants are characteristic of pancreatic cells at each stage of embryonic development. Using immunohistochemical markers, we have demonstrated that the cells of several pancreatic tumors express some fetal proteins characteristic of embryonic cells of the pancreas. We propose that the presence of fetal antigens and proteins in the tumor is a sign of a lower tumor differentiation and a less favorable prognosis.

[Quantitative assessment of beta-cell ultrastructure from mono- and polyhormonal insulinomas].

Surgical biopsies from 21 patients with syndrome of organic hyperinsulinism were studied. Precise quantitative characteristics of "typical" and "atypical" beta-granules in tumor cells were obtained by means of quantitative and qualitative analysis. The criteria for establishing the tumor type (mono- or polyhormonal) and the degree of hormonal activity are established.

[Neuroendocrine tumors of pancreas (clinicomorphological, immunohistochemical and electron microscopic study)].

Neuroendocrine tumors of the pancreas were studied by histology, immunohistochemistry and electron microscopy. Tumors associated with organic hyperinsulinism showed heterogeneity in their ultrastructure, functional and proliferation activity. More than half of these tumors are multihormonal and 15% of them developed from polypotent cells which are capable for several types of differentiation.