Cytogenetic analysis of 13 mesenchymal stem cell cultures isolated from normal human adipose tissue was carried out at different stages of culturing. The incidence of chromosomes 6, 8, 11, and X aneuploidy and polyploidy was studied by fluorescent in situ hybridization. During the early passages, monosomal cells were more often detected than trisomal ones. A clone with chromosome 6 monosomy was detected in three cultures during late passages.

We elaborated a method of preparing cytogenetic preparations of cultured multipotent mesenchymal stromal cells from the adipose tissue. It was found that karyotypic changes (monosomy, translocations) appear in some samples during culturing. Clones with changed karyotype were detected in 11-14-passage cultures from 2 of 7 individuals. The percent of aberrant cells in cultures from different individuals varied from 1.5 to 5.95 per 100 cells, which attested to karyotype instability. These data substantiate the need for cytogenetic control of cells before their transplantation into donor organism and further investigation of chromosome variability in stem cells.

The incidence of autosomes 6 and 8 aneuploidy in stem cell cultures derived from adipose tissue was evaluated at different stages of culturing. Monosomy was more incident than trisomy during the early passages. Distribution of cultures by the incidence of aneuploidy in different chromosomes was virtually the same. Clones with chromosome 6 monosomy were detected in two cultures during late passages.

We analyzed the expression of 15 cancer/testis and four melanoma differentiation antigens in 21 metastatic melanoma cell lines using reverse transcriptase-polymerase chain reaction (RT-PCR) assay. On the basis of morphological characteristics, tumor cell lines were divided into three groups with high, moderate, and low grade of differentiation. Evaluation of gene expression and melanoma cell morphology has revealed a correlation between increased expression of cancer/testis genes and differentiation grade of cancer cells. The gene expression pattern for lymph node metastases and primary tumors exhibits the distribution of expression level and frequency similar to that found for established cell lines. Nevertheless, only 60% lymph node metastases or primary tumor tissue of randomly selected patients show marked expression of the most prominent cancer/testis genes, and almost 90% lesion tissue expresses at least one of 15 cancer/testis genes.