The organization and intranuclear localization of nucleic acids and regulatory proteins contribute to both genetic and epigenetic parameters of biological control. Regulatory machinery in the cell nucleus is functionally compartmentalized in microenvironments (focally organized sites where regulatory factors reside) that provide threshold levels of factors required for transcription, replication, repair and cell survival. The common denominator for nuclear organization of regulatory machinery is that each component of control is architecturally configured and every component of control is embedded in architecturally organized networks that provide an infrastructure for integration and transduction of regulatory signals. It is realistic to anticipate emerging mechanisms that account for the organization and assembly of regulatory complexes within the cell nucleus can provide novel options for cancer diagnosis and therapy with maximal specificity, reduced toxicity and minimal off-target complications.