The genomes of all living organisms are extremely stable. DNA in the cell is replicated during cell division and passes all the genetic information to the next generation. It is essential for all living organisms to ensure proper functioning and propagation of their genetic information. Due to constant exposure of the genome to various endogenous and exogenous agents, however, the DNA becomes damaged leading to a large variety of DNA lesions.

Cord blood is alternative source of the haematopoietic stem cells (HSC) in relation to bone marrow and peripheral blood. Advantage of the cord blood (CB) is its relative accessibility as a source of HSC. HSC of CB present bigger proliferative potential than HSC of bone marrow and peripheral blood. Moreover they evoke weaker GvH reaction. The disadvantage of CB is its small amount obtain- able once for all. It can be applied to allogenic transplantation only, although, the banking of CB is becoming popular as a source of HSC for future autologous transplantation.