  Cosmological inflation remains to be a unique mechanism of generation of
plausible initial conditions in the early universe. In particular, it generates
the primordial quasiclassical perturbations with power spectrum determined by
the fundamental principles of quantum field theory. In this work, we pay
attention to the fact that the quasiclassical perturbations permanently
generated at early stages of inflation break homogeneity and isotropy of the
cosmological background. The evolution of the small-scale quantum vacuum modes
on this inhomogeneous background results in statistical anisotropy of the
primordial power spectrum, which can manifest itself in the observable
large-scale structure and cosmic microwave background. The effect is predicted
to have almost scale-invariant form dominated by a quadrupole and may serve as
a non-trivial test of the inflationary scenario. Theoretical expectation of the
magnitude of this statistical anisotropy depends on the assumptions about the
physics in the trans-Planckian region of wavenumbers.
