  Higher twist effects in the deeply inelastic scattering are studied. We start
with a short review of the theoretical results on higher twists in QCD. Within
the saturation model we perform a twist analysis of the nucleon structure
functions FT and FL at small value of the Bjorken variable x. The parameters of
the model are fitted to the HERA F2 data, and we derive a prediction for the
longitudinal structure function FL. We conclude that for FL the higher twist
corrections are sizable whereas for F2 = FT + FL there is a nearly complete
cancellation of twist-4 corrections in FT and FL. We discuss a few consequences
for future LHC measurements.
