2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/222915I review our recent attempts toward obtaining the MSSM from string orbifold compactification. The required constraints are the existence of three families and R parity, vectorlike exotics, one pair of Higgs doublets, and the SU(5)$'$ hidden sector for dynamical breaking of SUSY toward a GMSB scenario. We also comment on the threshold correction which are influenced by a power law evolution of gauge couplings through the KK radius in non-prime orbifolds and can be used to fit the couplings.18 pages with 11 figures. Talk presented at "GUT Worksop", Ritsumeikan Univ., Japan, 17-19 Dec. 2007High Energy Physics - Phenomenologytext