Despite intensive research, brain tumor remains one of the deadliest forms
of cancer with rapid progression and poor prognosis. A brain tumor is physically,
emotionally, socially, and financially challenging not only for the patient but also for
the caregiver. Morbid conditions like seizures, paralysis, cognitive impairment, and
permanent neurological damage are the potential impacts of either the disease or
therapy. Poor long-term survival with the 5-year and 10-year survival rates of almost
36% and 31%, respectively, adds to the burden. Animal models have undergone
constant development with time and remain an indispensable tool for exploring the
underlying pathophysiological mechanism and evaluating potential therapeutic
strategies. Initial brain tumor models used chemical carcinogens to induce brain
tumors, with nitrosourea derivatives being the favorable choice. These tumors could be
maintained easily under in vitro conditions as cell lines and grafted in suitable
syngeneic or xenogeneic hosts to study the cellular and physiological features of
different types of brain tumors. The advent of transgenic technology has revolutionized
animal modeling by allowing the manipulation of the host genome. Transgenic animals
with gain/loss of function (knock-in/knockout) can be produced to investigate the role
of any specific protein/gene involved in the cell cycle, metabolism, and signal
transduction. Since the first oncomice in the 1980s, the transgenic technique and the
subsequent expression of the transgene have been carefully worked out in mice. The
role of different mutations, tumor suppressors, and oncogenes has also been studied.
2D and 3D in vitro techniques for faster evaluation and pre-screening of drugs have
been established to mimic the brain microenvironment by manipulation of the culture
conditions. Furthermore, a brief summary of non-rodent models and their potential
applications has been discussed.
Keywords: Animal models, Brain tumor, Chemical models, Genetic models, invitro
models, Non-rodent models, Oncogenic virus, Syngeneic models, Xenograft
models.
