  We consider the Polyakov loop-extended two flavor chiral quark--meson model
and discuss critical phenomena related with the spontaneous breaking of the
chiral symmetry. The model is explored beyond the mean-field approximation in
the framework of the functional renormalisation group. We discuss properties of
the net-quark number density fluctuations as well as their higher cumulants. We
show that with the increasing net-quark number density, the higher order
cumulants exhibit a strong sensitivity to the chiral crossover transition. We
discuss their role as probes of the chiral phase transition in heavy-ion
collisions at RHIC and LHC.
