[Reed nevus and cutaneous melanoma in children: an immunohistochemical study]. / Nevus Rida i melanoma kozhi u detei. Immunogistokhimicheskoe issledovanie.

Certain difficulties arise in the differential diagnosis between Reed nevus that is common in children and adolescents and cutaneous melanoma that is extremely rare in patients of this age group. In addition to the classical histological examination, an immunohistochemical test for marker proteins is carried out to improve the accuracy of the diagnosis of pigmented skin neoplasms. OBJECTIVE: To evaluate the suitability of a set of proteins (cyclin D1, p16INK4a, and HLA class I antigens) in the differential diagnosis of Reed nevus and cutaneous melanoma in children and adolescents. MATERIAL AND METHODS: Three samples of pigmented skin neoplasms were taken during surgical treatment in patients at the Blokhin National Medical Research Center of Oncology: two samples of Reed nevus (from a 9-year-old girl and a 15-year-old boy) and a sample of cutaneous melanoma that had developed in an 8-year-old boy. The materials were presented by paraffin blocks. Immunohistochemical staining was performed using antibodies against cyclin D1, p16INK4a, and HLA class I antigens. RESULTS: Differences were found between nevus and melanoma in the expression of all three markers. Thus, the nuclear expression of cyclin D1, a proliferation activator, occurred in some cells in the nevus samples and in the vast majority of cells in the melanoma samples. The nuclear expression of the cell cycle inhibitor p16INK4a was dramatically reduced in melanoma compared to nevus. HLA class I antigens were detected on the surface of individual nevus cells, but were completely absent on the membranes and in the cytoplasm of melanoma cells, which could promote the evasion of this tumor from the body's immunological supervision. CONCLUSION: Immunohistochemical test for the proteins cyclin D1, p16INK4a, and HLA class 1 antigens is a promising approach to differentially diagnosing between Reed nevus and cutaneous melanoma in children and adolescents.

Characteristics of Mel Ibr Melanoma Line Subclone after Treatment with Chicken Embryo Extract.

We continue analysis of the phenotype of human melanoma cell Mel Ibr subclone obtained previously by treatment of the parental cell line by chicken embryo extract. The present study is focused on detection of markers of epithelial-mesenchymal transition that determine enhanced metastatic and invasive potential of malignant tumors of various locations. Analysis of the expression of E-cadherin and vimentin genes in the subclone and parental cells detected activation of epithelial-mesenchymal transition in the subclone. Immunological markers CD90, CD271, and CD95 were present in the parental population, but were not detected on the subclone cells. In contrast to the parental line, cells of the analyzed subclone retain viability in serum-free medium and formed vessel-like structures characteristic of vasculogenic mimicry.

Changes in the Morphological and Immunological Characteristics of Mel Ibr Melanoma Cells in Response to Chicken Embryo Extract.

Exposure of Mel Ibr human melanoma cells to chicken embryo extract resulted in the appearance of a subclone with morphological and growth characteristics similar to those of embryonic stem cells. The subclone differed from the parental line cells by a sharply reduced percentage of HLA-DR(+) and CD54(+) cells, a significantly elevated percentage of CD63(+) cells, and appearance of CD133(+) and Oct-4A(+) cells. Hence, the subclone cells were characterized by the same features as stem tumor cells and could be responsible for further progress of tumor growth.

[Melanoma cell lines as the basis for antitumor vaccine preparation].

The aim of the study was to obtain cell lines from tumor samples, and to determine phenotypic cell characteristics in order to choose the optimal line for vaccine preparation. 15 cell lines with stable growth, varying in cultural growth character and cytomorphology, were obtained from samples taken from patients with metastatic skin melanoma. Immunofluorescense method was used to determine the expression of T- and B-lymphocyte markers, antigens of major histocompatibility complex (MHC) class I and II, and CD86 co-stimulating molecule in the cell lines. The expression of melanocyte differentiation antigens and cancer/testicular antigens was evaluated using immunocytochemical assay. The results allowed the authors to distinguish three types of melanoma cell lines according to the expression of MHC molecules: MHC-negative; MHC class I positive; MHC classes I and II positive.