GMOs containing nucleic acid fragments with neoplastic transforming potential

The ZKBS statement "Assessment of genetically modified organisms into which nucleic acid segments with neoplastic transforming potential have been introduced" was updated in February 2025. Such nucleic acid segments can lead to the development of malignant tumors in laboratory animals after injection or application to skin lesions. They could also pose a risk to humans if these nucleic acids were transferred to body cells. If nucleic acid segments encoding proteins with transforming potential for mammalian cells are introduced into recipient organisms in risk group 1, the resulting GMOs are classified in risk group 1 if the vector-recipient system used involves recognized biological safety measures (according to Section 7 Paragraphs 3 and 5 of the Genetic Engineering Ordinance). With the updated statement , primary cells and established cell lines can now also be recognized as part of a biological safety measure according to Section 7 Paragraph 3 of the GenTSV , provided they do not regenerate into an organism spontaneously or during the intended genetic engineering work and do not contain contamination from microorganisms or exogenous viruses. Another change concerns the use of Escherichia coli BL21 strains . If nucleic acid fragments with neoplastic transforming potential are introduced into Escherichia coli BL21 strains, the GMOs are classified in risk group 1 if the vectors used meet the requirements of Section 8, Paragraph 2 of the GenTSV (vectors as part of a biological safety measure). The updated ZKBS statement, including the assessment and the corresponding justification, can be accessed under the reference number 08020203.0002.00051 .