Why are animal experiments carried out at DKFZ?
The aim of the German Cancer Research Centre’s work is to unravel the causes of cancer, develop new treatment options based on this knowledge, and identify new approaches to early detection and prevention. The well-being and health of humans are at the heart of this work.
In addition to research aimed directly at improving cancer treatment, basic biomedical research accounts for a significant proportion of the scientific activities at the DKFZ. This involves understanding biological processes at the cellular and molecular level and the disruptions to these processes that can lead to the development of cancer. To answer such fundamental questions, research involving animals remains indispensable. The results of this basic research provide the foundation upon which novel therapeutic approaches can be developed.
Why are animal experiments indispensable in cancer research at DKFZ?
To make progress in the fight against cancer, scientists use all available methods and model systems: this involves working at the level of the smallest biological building blocks as well as with cell and tissue cultures, tumour tissue samples, organoids and computer models. Epidemiological and clinical studies also provide valuable results. However, cancer is a disease that affects the whole body. As a tumour grows and spreads, the cancer cell comes into close contact with countless other cells and tissues throughout the body, to which it sends signals and from which it receives messages in turn. All these interactions play a key role in the development and progression of cancer. This complexity can only be understood with the help of a living organism; consequently, animal testing remains indispensable in cancer research at present.
Which animal species are used in animal experiments at DKFZ and where do the animals come from?
99.9 per cent of the animals used at DKFZ are mice. In addition, there are research groups that also require other animal species, such as Xenopus frogs, rats and guinea pigs, for their research. The mice are largely bred at the DKFZ. Some mice, as well as the other animal species, come from commercial breeders of laboratory animals or from other laboratory animal facilities.
Who takes care of the laboratory animals at DKFZ?
The Central Animal Laboratory (ZTL) ensures that the animals are cared for in accordance with animal welfare standards, thanks to an experienced team of animal caretakers, veterinarians and administrative staff. The animal caretakers are responsible for the day-to-day care of the animals – 365 days a year – checking their health, monitoring their food and water intake, ensuring cleanliness, observing the animals’ behaviour and documenting any abnormalities. Every single animal is examined and assessed individually every day.
Animals used in experiments are additionally looked after by the scientific staff. The veterinarians support both the animal caretakers and the scientists conducting animal experiments and are responsible for the veterinary care of the animals. Furthermore, the animal welfare officers support the animal experimentation projects. They and the relevant veterinary authority also check compliance with legal requirements and individual conditions during regular (mostly unannounced) visits.
How are laboratory animals housed at DKFZ?
The requirements for the housing of laboratory animals are laid down by law and approved by the authorities. The mice at DKFZ are housed in so-called individually ventilated cages (IVC), which minimise exposure to noise and dust as well as the risk of infection. Each cage (housing a maximum of five adult mice) contains bedding, food and water, as well as nesting material for enrichment and nest-building, gnawing sticks and a tube to serve as a shelter. Additional cage enrichment items (mouse house, running wheel, etc.) are added to the cage as required. Cage temperature, humidity, light intensity and the day/night cycle, as well as the quality of food and water, are strictly monitored. The health of the animals is the top priority, and this requires constant and very extensive measures.
Who is permitted to carry out animal experiments at DKFZ?
All persons involved in any form of animal experimentation – scientists, technical staff, animal caretakers and veterinarians – must have completed appropriate professional training and training in laboratory animal science. In addition, there is a continuous obligation for these groups to undergo further training. These requirements are regulated by law (EU Directive 2010/63, Animal Welfare Act, Animal Welfare Laboratory Animal Ordinance) and are checked before work with laboratory animals begins, during regular inspections by the Veterinary Office, and internally.
What legal regulations apply to animal experiments at DKFZ?
The key legal regulations are those of EU Directive 2010/63, the German Animal Welfare Act (TierSchG) and the Animal Welfare Laboratory Animal Ordinance (TierSchVersV), the implementation of which is continuously monitored internally by the animal welfare officers and externally by the veterinary authority. The so-called ‘3R principle’ also applies at DKFZ: we carry out as few animal experiments as possible (Reduction), we strive to reduce the burden on the animals through continuous development (Refinement) and, wherever possible, to replace them with alternatives (Replacement).
Who monitors compliance with animal welfare standards and legal requirements?
Animal welfare standards are checked by the licensing and veterinary authorities even before a laboratory animal facility begins operations. As the operator, DKFZ must ensure that structural, technical and personnel requirements are met. Scientists planning animal experiments must set out in writing, in an animal experimentation application, the indispensability of the experiment, its ethical justifiability, the lack of alternatives, and the scientific necessity of the required number and species of animals, as well as describe in detail all experiments and the expected burden on the animals. The animal experimentation application goes through several review stages: DKFZ’s animal welfare officers, the licensing authority and, finally, an independent commission under Section 15 of the Animal Welfare Act (TierSchG), which is appointed by the authority and comprises experts and members of animal welfare organisations. The entire process usually takes several months. Only once all ambiguities have been resolved and the legitimacy, suitability, appropriateness and indispensability of the project have been demonstrated is an animal experimentation project approved, specifying a particular number of animals and a fixed duration.
During ongoing operations, everyone from animal carertakers and veterinarians to scientific staff is obliged to comply with animal welfare standards. The experiments must adhere strictly to the terms of the authorisation; any potential changes require renewed official approval.
Animal welfare officers also play an important role (Section 10 of the Animal Welfare Act). They are independent and not subject to instructions, and are officially appointed by the licensing authority. They are qualified in their field and in laboratory animal science, monitor the experimental projects and ensure compliance with individual conditions. Furthermore, they are generally required to promote animal welfare.
When and how are so-called alternative methods used at DKFZ?
The legal regulations stipulate that, wherever possible, animal experiments should be avoided and so-called alternative methods used. Scientists at DKFZ can investigate many research questions using living cells or tiny tissue structures, known as organoids, which are grown in a culture dish. There are now also so-called ‘organ-on-a-chip’ methods, which allow defined biological processes to be simulated on a micro-scale using cells from various tissues. Computer simulations also help to answer certain questions, as do specialised imaging techniques. However, these techniques are not capable of fully replicating the complex interplay of a tumour within the entire organism. For this reason, animal testing remains indispensable in many areas of cancer research.
How is burden on the animals minimised during the experiments?
Legal requirements stipulate that distress (i.e. pain, suffering, harm) must always be kept to a minimum in any experiment. This must be explained when applying for an animal experiment. Close cooperation between animal caretakers, veterinarians and researchers ensures that any animals showing signs of abnormality are reported via a digital programme. This allows measures to be taken quickly – even at weekends and on public holidays. In addition, the DKFZ Animal Welfare Committee meets regularly to review experimental projects, assess the associated distress and develop measures to reduce this to a minimum. The explanation and classification of levels of distress are defined in EU Directive 2010/63 and are explained on the ‘Understanding Animal Testing’ website: https://www.tierversuche-verstehen.de/die-belastung-von-versuchstieren-druck-version/
Why are mice frequently used in cancer research?
The mouse is the most commonly used laboratory animal and also plays a key role in cancer research. An important reason for this, apart from their biological similarity to humans, is that mice have long been successfully genetically modified. By, for example, selectively switching genes on and off, important bodily functions can be examined in isolation and better understood. The short generation interval allows researchers to study several generations in a relatively short time and observe the progression of diseases. Thanks to their small size, they can also be kept well under controlled laboratory conditions, which enables reliable and comparable results.
Why can’t all laboratory-bred animals be used in animal experiments?
Firstly, according to the laws of inheritance, the breeding of genetically modified mice always results in some animals that do not possess the genetic characteristics required for the experiment. Furthermore, depending on the research question or requirements for comparability, a specific age and/or gender is often required. In such cases, we first check whether the animals can be used in other experiments or for other purposes. If this is not the case, the mice or rats are kept in our animal facilities. Should they then become terminally ill or should the facility reach maximum capacity, they are euthanised in accordance with animal welfare standards. Detailed background information on this can be found on the ‘Understanding Animal Testing’ website via the following link: Understanding Animal Testing website: Animals that cannot be used