Gamma Cas and its dozen analogs comprise a small but distinct class of X-ray
sources. They are early Be-type stars with an exceptionally hard thermal X-ray
emission. The X-ray production mechanism has been under intense debate for ~30 years
among a small group of people. Though the debate is not well recognized outside of the
group, its outcome will give impacts in much wider fields of astrophysics, including the
binary evolution and the disk astrophysics.

Two competing ideas for the X-ray emission have been (i) the magnetic activities in the Be
star and its disk and (ii) the mass accretion onto the unidentified white dwarf (WD). In
this work, we adopt the latter as a working hypothesis and apply physical models
developed to describe the X-ray spectra of classical WD binaries containing a late-type
companion. Models of non-magnetic and magnetic accreting WDs were applied to gamma Cas
and its brightest analog HD 110432 using the Suzaku and NuSTAR data. The spectra were
fitted by the two models, including the Fe fluorescence and the Compton reflection in a
consistent geometry. The derived physical parameters, such as WD mass and mass accretion
rate, are in a reasonable range in comparison to their classical WD binary
counterparts. Additional pieces of evidence in the X-ray spectra (partial covering, Fe L
lines, Fe I fluorescence) were not conclusive enough to classify these two sources into
a sub-class of accreting WD binaries. We discuss further observations, especially
long-term temporal behaviors, which are important to elucidate the nature of these
sources more if indeed they host accreting WDs.