Study of genomic parameters in breast cancer

The telomere of the short arm of each acrocentric human chromosome has a satellite stalk, referred to as a NOR (nucleolar organizer regions), composed of heterochromatin. Human NORs contain ≥600 rRNA gene copies. Only around 50% of these copies are transcribed. Some chromatid satellite stalks are connected, forming “satellite associations” (SAs). SAs are always transcriptionally active. The study of the patterns of function of nuclear organizers in the conditions of tumor of various organs is of particular importance. The aim of our work was to determine the frequency of active nucleus organizers and acrocentric chromosome associations in lymphocytic culture cells of individuals with ductal breast cancer using a cultivation of lymphocytes, combination of the silver impregnation method and the G-bending method, and IKAROS carotyping system. Combinative usage of these methods allowed us to determine exactly which chromosome activity is increased in the case of this pathology. We determined, that the activity of satellite stalks of chromatids on homologous chromosomes (15:15 and 21:21) was significantly increased in patients with ductal breast cancer (DBC) compared with the activity of this chromatids in healthy middle-aged individuals (p <0.001). The types of association of homologous chromosomes chromatids (15:15 and 21:21) in patients with DBC was significantly increased in comparison with healthy middle-aged individuals (p<0.001). Our results indicated that there is a differential activity of satellite stalks of 15:15 and 21:21 chromosome chromatids in patients with DBC compared to the control group. The study of ribosomal cistrons in acrocentric chromatids and their role in pathology is a new direction in medicine, offering new capabilities for the diagnosis of diseases and defining new treatment strategies in the future.

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