  The bosonic contributions to the photon mass are shown to be of the same form
as the fermionic contributions, but of opposite sign. A mass sum rule for
bosons and fermions follows from gauge invariance. Assuming completeness of the
standard model the top quark mass can be predicted. Effectively only the
W-bosons contribute, giving a lowest order prediction of 85.1 GeV for the mass
of top quark, on the low side of currently accepted estimates.
